# GCN_circulars

GRB_name: GRB230216B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33341
SUBJECT: GRB 230216B: AstroSat CZTI detection
DATE:    23/02/18 06:55:51 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

P. Shetty (IITB), P K. Navaneeth (IUCAA), G. Waratkar (IITB), M. Dixit 
(IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka 
University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report 
on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 
2021, JApA, 42, 73) showed the detection of a long GRB 230216B which was 
also detected by CALET-GBM (GCN Notice. 1360609287).

The source was clearly detected in the 20-200 keV energy range. The 
light curve peaks at 2023-02-16 19:03:30 UTC. The measured peak count 
rate associated with the burst is 319.5 (+96.6 -57.1) counts/s above the 
background in the combined data of all four quadrants, with a total of 
634 (+222 -225) counts. The local mean background count rate was 405.3 
(+3.9 -5.0) counts/s. Using cumulative rates, we measure a T90 of 5.85 
(+3.85 -2.20) s.

It was also clearly detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at 
http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led 
consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, 
and PRL. The Indian Space Research Organisation funded, managed, and 
facilitated the project.

Links:
------
[1] http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB230207B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33342
SUBJECT: GRB 230207B: CALET Gamma-Ray Burst Monitor detection
DATE:    23/02/18 08:37:02 GMT
FROM:    Yuta Kawakubo at Louisiana State U./CALET  <kawakubo1@lsu.edu>

S. Torii (Waseda U), A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka (ICRR), Y. Akaike, K. Kobayashi (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC),
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long GRB 230207B (AGILE detection: Casentini et al., 
GCN Circ 33296; Swift-BAT-GUANO detection: Raman et al.,
GCN Circ. 33298; Detection by GRBAlpha: Dafcikova et al.,
GCN Circ. 33303) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 04:40:43.38 UTC on 7 February 2023
(http://cgbm.calet.jp/cgbm_trigger/flight/1359779945/index.html).
The burst signal was seen by all CGBM detectors.

The burst light curve shows a single pulse that starts
at T+2.1 sec, peaks at T+5.2 sec, and ends at T+28.2 sec.
The T90 and T50 durations measured by the SGM data are 14.2 +/- 0.8 sec
and 4.7 +/- 0.1 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1359779945/

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.


GRB_name: GRB230217A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33343
SUBJECT: GRB 230217A: AGILE/MCAL detection
DATE:    23/02/18 10:41:34 GMT
FROM:    Claudio Casentini at INAF-IAPS  <claudio.casentini@inaf.it>

C. Casentini (INAF/IAPS), F. Verrecchia (SSDC, and INAF/OAR), F. Longo
(Uni. Trieste, INFN Trieste) M. Tavani
(INAF/IAPS, and Univ. Roma Tor Vergata), C. Pittori, F. Lucarelli,
A. Argan, M. Cardillo, Y. Evangelista, L. Foffano, G. Piano
(INAF/IAPS), A. Addis, L. Baroncelli, A. Bulgarelli, A. Di Piano,
V. Fioretti, G. Panebianco, N. Parmiggiani (INAF/OAS-Bologna), M. Romani
(INAF/OA-Brera), M. Marisaldi (INAF/OAS-Bologna, Bergen University),
M. Pilia, A. Trois (INAF/OA Cagliari), I. Donnarumma, E. Menegoni,
A.Ursi (ASI), A. Giuliani (INAF/IASF-Mi) and P. Tempesta (TeleSpazio),
report on behalf of the AGILE Team:

The AGILE satellite detected the short GRB 230217A at
T0 = 2023-02-17 21:53:10.87 (UTC), reported by Fermi/GBM (GCN #33338) and
Swift BAT (GCN #33339).

The burst is clearly visible in the AGILE scientific ratemeters of the
MiniCALorimeter (MCAL; 0.4-100 MeV), and in all the panels of the
AntiCoincidence detectors (AC Top, 50-200 keV; AC Lat, 80-200 keV).
The event lasted about 2 s and it released a total number of 7554 counts
in the MCAL detector (above a background rate of 529 Hz), and 38605 counts
in the AC Top detector (above a background rate of 3530 Hz).
The AGILE ratemeters light curves can be found at:
http://www.agilescienceapp.it/notices/GRB230217A_AGILE_RM_ND.png .

The event also triggered a high-time resolution MCAL data acquisition,
from T0-0.7 s to T0+5.8 s (UTC), and released 2515 counts in the detector,
above a background rate of 776 Hz. The MCAL light curve can be found at:
http://www.agilescienceapp.it/notices/GRB230217A_082311_603755590.000000.png
.

The time-integrated spectrum of the burst between T0-1s and T0+1s, fitted
in the energy range 0.4-10 MeV with a p.l. with ph. ind. = -2.12 (+/-0.08)
resulting in a reduced chi-squared of 0.92 (48 d.o.f.)
and a fluence of 4.05e-06 ergs/cm^2 (90% confidence level),
in the same energy range.

At the T0, the event was 59 deg off-axis.
Additional analysis of AGILE data is in progress.
Automatic MCAL GRB alert Notices can be found at:
https://gcn.gsfc.nasa.gov/agile_mcal.html


GRB_name: GRB230218A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33344
SUBJECT: GRB 230218A: Fermi GBM Final Real-time Localization
DATE:    23/02/18 15:56:53 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 15:46:27 UT on 18 Feb 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230218A (trigger 698427992.71955 / 230218657).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 39.6, Dec = 55.1 (J2000 degrees, equivalent to J2000 02h 38m, 55d 06'), with a statistical uncertainty of 16.0 degrees.

The angle from the Fermi LAT boresight is 10.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230218657/quicklook/glg_skymap_all_bn230218657.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230218657/quicklook/glg_healpix_all_bn230218657.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230218657/quicklook/glg_lc_medres34_bn230218657.gif


GRB_name: GRB230218A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33345
SUBJECT: GRB 230218A is not a GRB
DATE:    23/02/19 01:34:07 GMT
FROM:    Suraj Poolakkil at UAH  <sp0076@uah.edu>

S. Poolakkil (UAH) reports on behalf of the Fermi Gamma-ray Burst Monitor
Team:

"The Fermi Gamma-ray Burst Monitor (GBM) trigger 698427992/230218657 at
15:46:27.72 UT
on 18 February 2023, tentatively classified as GRB 230218A (GCN 33344), is
in fact not due
to a GRB. This trigger is likely due to LS V +44 17 / RX J0440.9+4431."


GRB_name: GRB230217A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33348
SUBJECT: GRB 230217A: Swift-XRT observations
DATE:    23/02/19 07:48:15 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

M. Capalbi (INAF-IASFPA), J.A. Kennea (PSU), A. Tohuvavohu (U.
Toronto), D.N. Burrows (PSU), K.L. Page (U. Leicester), A.P. Beardmore
(U. Leicester), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR)
and M. J. Moss (GWU) report on behalf of the Swift-XRT team:

We have analysed 4.8 ks of Photon Counting (PC) mode XRT data for the
Swift-BAT-detected burst GRB 230217A (Moss et al. GCN Circ. 33339),
collected between T0+45.8 ks and T0+84.4 ks. 

Two uncatalogued X-ray sources have been detected consistent with being
within 296 arcsec of the Swift-BAT position, however none of them is
above the RASS limit or shows definitive signs of fading. Therefore, at
the present time we cannot identify which, if any, is the afterglow.
Details of these sources are given below:

Source 3:
  RA (J2000):  280.7700  =  18:43:4.80
  Dec (J2000): -28.8374  =  -28:50:14.6
  Error: 4.7 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: 0.0144 [+0.0022, -0.0021] ct s^-1   
  Distance: 67 arcsec from Swift-BAT position.
  Flux: (6.48 [+0.98, -0.94])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 5:
  RA (J2000):  280.7763  =  18:43:6.30
  Dec (J2000): -28.7796  =  -28:46:46.7
  Error: 6.4 arcsec (radius, 90% conf.)
  Count-rate: (1.43 [+0.85, -0.64])e-3 ct s^-1  
  Distance: 275 arcsec from Swift-BAT position.

Six uncatalogued sources were also detected too far from the GRB
position to be likely afterglow candidates.

The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
https://www.swift.ac.uk/ToO_GRBs/01154967.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB230217A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33349
SUBJECT: Konus-Wind detection of GRB 230217A
DATE:    23/02/19 12:10:55 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, D. Frederiks, M. Ulanov, A. Tsvetkova,
A. Lysenko, A. Ridnaia, and T. Cline
on behalf of the Konus-Wind team, report:

The short-duration GRB 230217A
(Fermi-GBM detectin: The Fermi-GBM team, GCN Circ. 33338;
Swift-BAT detection: Moss et al., GCN Circ. 33339;
CALET-GBM detection: Torii et al., GCN Circ. 33342;
AGILE-MCAL detection: Casentini et al., GCN Circ. 33343)
triggered Konus-Wind at T0=78786.119 s UT (21:53:06.119).

The burst light curve shows a multi-peaked structure
which starts at ~T0-0.2 s and has a total duration of ~0.9 s.
The emission is seen up to ~6 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB230217_T78786/

As observed by Konus-Wind, the burst
had a fluence of 2.74(-0.35,+0.39)x10^-5 erg/cm2,
and a 16-ms peak flux, measured from T0+0.128 s,
of 9.45(-1.84,+1.94)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.81(-0.13,+0.14)
and Ep = 1367(-240,+309) keV (chi2 = 105/98 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta <-2.7
(chi2 = 105/97 dof).

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.


GRB_name: GRB230220A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33352
SUBJECT: GRB 230220A: MAXI/GSC detection
DATE:    23/02/20 10:29:08 GMT
FROM:    Hitoshi Negoro at Nihon U  <negoro.hitoshi@nihon-u.ac.jp>

S. Nawa (Chuo U.), H. Negoro, M. Nakajima, K. Kobayashi, M. Tanaka, Y. Soejima (Nihon U.), 
T. Mihara, T. Kawamuro, S. Yamada, T. Tamagawa, M. Matsuoka (RIKEN), 
T. Sakamoto, M. Serino, S. Sugita, H. Hiramatsu, H. Nishikawa, A. Yoshida (AGU), 
Y. Tsuboi, J. Kohara, S. Urabe, N. Nemoto (Chuo U.), M. Shidatsu, M. Iwasaki (Ehime U.),
N. Kawai, M. Niwano, R. Hosokawa, Y. Imai, N. Ito, Y. Takamatsu (Tokyo Tech), 
S. Nakahira,  S. Ueno, H. Tomida, M. Ishikawa,  T. Kurihara (JAXA), 
Y. Ueda, S. Ogawa, K. Setoguchi, T. Yoshitake, K. Inaba, Y. Nakatani (Kyoto U.), 
M. Yamauchi, T. Sato, R. Hatsuda, R. Fukuoka, Y. Hagiwara, Y. Umeki (Miyazaki U.), 
K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M. Sugizaki (NAOC), W. Iwakiri (Chiba U.) 
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source 
at 08:55:58 UT on 20  Feb 2023. Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (346.565 deg, 18.607 deg) = (23 06 15, +18 36 25) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.22 deg and 0.19 deg, respectively.
The roll angle of long axis from the north direction is 153.0 deg counterclockwise.
Without assumptions on the source constancy, we obtain a rectangular error box 
for the transient source with the following corners.
(196.900, -21.911) deg = (13 07 36, -21 54 39) (J2000)
(196.998, -22.143) deg = (13 07 59, -22 08 34) (J2000)
(198.373, -21.637) deg = (13 13 29, -21 38 13) (J2000)
(198.273, -21.406) deg = (13 13 05, -21 24 21) (J2000)
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 182 +- 28 mCrab (4.0-10.0keV, 1 sigma error).
There was no significant excess flux in the previous transit at 07:22 UT with an upper limit of 20 mCrab.


GRB_name: GRB230217A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33353
SUBJECT: GRB 230217A: Fermi GBM observation
DATE:    23/02/20 14:57:16 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

P. Veres (UAH) reports on behalf of the Fermi GBM Team:

"At 21:53:10.69 UT on 17 February 2023, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 230217A (trigger 698363595 / 230217912).
which was also detected by the Swift/BAT (Moss et al., GCN 33339),
AGILE (Casentini et al., GCN 33343), CALET-GBM (Torii et al., GCN
33342) and Konus-Wind (Svinkin et al., GCN 33349). The GBM on-ground
location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 58 degrees.

The GBM light curve consists of a single pulse
with a duration (T90) of about 0.90 s (50-300 keV).
The time-averaged spectrum from T0s to T0+1.4 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.74 +/- 0.02 and
the cutoff energy, parameterized as Epeak, is 1497 +/- 63 keV.

The event fluence (10-1000 keV) in this time interval is
(1.81 +/- 0.02)E-5 erg/cm^2. The 64 ms peak photon flux measured
starting from T0+0.22 s in the 10-1000 keV band
is 93.1 +/- 2.8 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 1476 +/- 79 keV, alpha = -0.74 +/- 0.02 and beta = 3.07+/-0.82.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB230217A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33356
SUBJECT: GRB 230217A: Gemini-South Optical Observation
DATE:    23/02/20 18:26:01 GMT
FROM:    Brendan O'Connor at UMD  <oconnorb@umd.edu>

B. O'Connor (UMD, GWU) and E. Troja (UTV, ASU), report on behalf of a
larger collaboration:

We carried out optical observations with the 8.1m Gemini-South Telescope
in Cerro Pachon, Chile targeting the location of the short GRB 230217A
(Moss et al. GCN 33339). We observed the position of X-ray Source 3
reported by Capalbi et al. (GCN 33348) at 09:24:47 UT on 2023-02-20,
corresponding to ~2.5 d after the GRB trigger (Moss et al. GCN 33339,
Svinkin et al. GCN 33349, Veres et al. GCN 33353). The target was
observed during twilight for 300 s in i-band.

Within the source localization, we do not find any obvious counterpart
when compared to the PS1 catalog to depth i>22.8 AB mag (not corrected
for Galactic extinction along the line of sight). However, objects
fainter than the PS1 limits are resolved in our observation and will
require image subtraction to establish fading.

Further observations are planned.

We thank the staff of the Gemini Observatory for assistance in rapidly
obtaining these observations.


GRB_name: GRB230220B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33357
SUBJECT: GRB 230220B: Fermi GBM Final Real-time Localization
DATE:    23/02/20 21:35:14 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 21:25:05 UT on 20 Feb 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230220B (trigger 698621110.792684 / 230220892).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 45.2, Dec = 28.0 (J2000 degrees, equivalent to J2000 03h 00m, 28d 00'), with a statistical uncertainty of 7.0 degrees.

The angle from the Fermi LAT boresight is 70.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230220892/quicklook/glg_skymap_all_bn230220892.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230220892/quicklook/glg_healpix_all_bn230220892.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230220892/quicklook/glg_lc_medres34_bn230220892.gif


GRB_name: GRB230217A
Detection_method: VLA Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33358
SUBJECT: GRB 230217A: 6 GHz VLA observations
DATE:    23/02/20 22:04:09 GMT
FROM:    Genevieve Schroeder at Northwestern University  <genevieveschroeder2023@u.northwestern.edu>

G. Schroeder, W. Fong (Northwestern), E. Berger (Harvard), T. Laskar (Utah)
report:

"We observed the short GRB 230217A (Moss et al., GCN 33339; Casentini et
al., GCN 33343; Torii et al., GCN 33342; Svinkin et al., GCN 33349) with
the Karl G. Jansky Very Large Array (VLA) under program 23A-296 (PI:
Schroeder) beginning on 2023 February 18.67 UT (0.76 days post-burst) at a
mean frequency of 6 GHz. The VLA has a primary beam of ~7 arcmin at 6 GHz,
covering the entirety of the Swift/BAT position (Moss et al., GCN 33339).

We searched for radio sources near the two X-ray sources coincident with
the Swift/BAT localization found by Swift/XRT (Source 3 and Source 5,
Capalbi et. al GCN 33348), though neither X-ray source has been
definitively determined the X-ray afterglow. We detect radio sources
coincident with both XRT sources. Our preliminary results are as follows:

Source 3: flux of ~65 microJy (~9 sigma) at the position:

RA(J2000) = 18:43:04.948

Dec(J2000) = -28:50:16.60

with an uncertainty of ~0.3" in each coordinate.

Source 5: flux of ~20 microJy (~3 sigma) at the position:

RA(J2000) = 18:43:06.762

Dec(J2000) = -28:46:48.06

with an uncertainty of ~0.6" in each coordinate.

We thank the VLA staff for quickly approving and executing these
observations."


GRB_name: GRB230216B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33359
SUBJECT: GRB 230216B: CALET Gamma-Ray Burst Monitor detection 
DATE:    23/02/21 04:32:39 GMT
FROM:    Yuta Kawakubo at Louisiana State U./CALET  <kawakubo1@lsu.edu>

Y. Akaike  (Waseda U), A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka (ICRR), S. Torii, K. Kobayashi (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC),
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long GRB 230216B (AstroSat CZTI detection: Shetty et al.,
GCN Circ. 33341) triggered the CALET Gamma-ray Burst Monitor
(CGBM) at 19:03:22.03 UTC on 16 February 2023
(http://cgbm.calet.jp/cgbm_trigger/flight/1360609287/index.html).
The burst signal was seen by all CGBM detectors.

The burst light curve shows a multi-peaked structure that starts
at T+1.5 sec, peaks at T+4.9 sec, and ends at T+11.1 sec.
The T90 and T50 durations measured by the SGM data are 8.3 +/- 1.1 sec
and 3.1 +/- 0.4 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1360609287/

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.


GRB_name: GRB230217A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33360
SUBJECT: GRB 230217A: Gemini South optical upper limits
DATE:    23/02/21 07:27:44 GMT
FROM:    Eleonora Troja at GSFC  <eleonora.troja@nasa.gov>

E. Troja (UTV) and B. Oâ€™Connor (GWU) report:



We inspected the GMOS-S observations of the short GRB 230217A reported in
Oâ€™Connor et al. (GCN Circ. 33356). At the position of the radio source
(Schroeder et al., GCN Circ 33358) coincident with the X-ray source #3
(Capalbi et al. GCN Circ. 33348), no optical counterpart is detected down
to i>23 AB mag, not corrected for Galactic extinction. The lack of optical
detection does not rule out an afterglow origin for the X-ray source and
remains consistent with a power-law spectrum with slope beta_OX < 0.6.
Further observations are encouraged to establish variability.



Our images do not cover the position of the X-ray/radio source #5, which
lies just outside the BAT error circle.



We thank the staff of the Gemini Observatory for assistance in rapidly
obtaining these observations.


GRB_name: GRB230217A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33361
SUBJECT: GRB 230217A: AstroSat CZTI detection
DATE:    23/02/21 08:14:53 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

P K. Navaneeth (IUCAA), R. Gopalakrishnan (IUCAA), G. Waratkar (IITB), 
A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka 
University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report 
on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 
2021, JApA, 42, 73) showed the detection of a short GRB230217A which was 
also detected by Fermi-GBM (Fermi GBM team, GCN Circ. 33338), Swift-BAT 
(Moss et al., GCN Circ. 33339), AGILE/MCAL (Casentini et al., GCN Circ. 
33343), Swift-XRT (Capalbi et al., GCN Circ. 33348) and Konus-Wind 
(Svinkin et al., GCN Circ. 33349).

The source was clearly detected in the 20-200 keV energy range. The 
light curve peaks at 2023-02-17 21:53:10.9 UTC. The measured peak count 
rate associated with the burst is 6691 (+436, -444) counts/s above the 
background in the combined data of all quadrants, with a total of 3487 
(+142, -172) counts. The local mean background count rate was 454 (+9, 
-10) counts/s. Using cumulative rates, we measure a T90 of 0.77 (+0.19, 
-0.07) s.

It was also detected in the CsI anticoincidence (Veto) detector in the 
100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at 
http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led 
consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, 
and PRL. The Indian Space Research Organisation funded, managed, and 
facilitated the project.


GRB_name: GRB230220B
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33362
SUBJECT: Fermi GRB 230220B: Global MASTER-Net observations report 
DATE:    23/02/21 18:30:37 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 230220B ( Fermi GBM team, GCN 33357) errorbox  74491 sec after notice time and 74524 sec after trigger time at 2023-02-21 18:07:10 UT, with upper limit up to  17.9 mag. Observations started at twilight.  The observations began at zenith distance = 70 deg. The sun  altitude  is -9.8 deg. 

The galactic latitude b = -26 deg., longitude l = 155 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2200481

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   74555 | 2023-02-21 18:07:10 |         MASTER-SAAO | (03h 03m 16.78s , +27d 44m 15.6s) |   C |    60 | 13.8 |        
   74688 | 2023-02-21 18:09:23 |         MASTER-SAAO | (03h 12m 13.77s , +27d 45m 15.6s) |   C |    60 | 16.3 |        
   74688 | 2023-02-21 18:09:23 |         MASTER-SAAO | (03h 13m 10.41s , +27d 45m 00.7s) |   C |    60 | 16.2 |        
   74778 | 2023-02-21 18:10:53 |         MASTER-SAAO | (03h 03m 18.99s , +27d 44m 23.4s) |   C |    60 | 16.3 |        
   74778 | 2023-02-21 18:10:53 |         MASTER-SAAO | (03h 04m 15.47s , +27d 44m 08.6s) |   C |    60 | 16.2 |        
   74857 | 2023-02-21 18:12:13 |         MASTER-SAAO | (02h 29m 06.25s , +27d 44m 20.1s) |   C |    60 | 15.4 |        
   74858 | 2023-02-21 18:12:13 |         MASTER-SAAO | (02h 30m 02.34s , +27d 44m 03.8s) |   C |    60 | 15.6 |        
   74948 | 2023-02-21 18:13:44 |         MASTER-SAAO | (02h 38m 02.65s , +27d 45m 45.2s) |   C |    60 | 16.0 |        
   74948 | 2023-02-21 18:13:44 |         MASTER-SAAO | (02h 38m 58.83s , +27d 45m 28.5s) |   C |    60 | 16.2 |        
   75028 | 2023-02-21 18:15:04 |         MASTER-SAAO | (02h 46m 11.46s , +27d 45m 26.4s) |   C |    60 | 16.5 |        
   75028 | 2023-02-21 18:15:04 |         MASTER-SAAO | (02h 47m 07.74s , +27d 45m 09.6s) |   C |    60 | 16.6 |        
   75120 | 2023-02-21 18:16:35 |         MASTER-SAAO | (02h 55m 05.64s , +27d 44m 41.1s) |   C |    60 | 16.9 |        
   75120 | 2023-02-21 18:16:35 |         MASTER-SAAO | (02h 56m 02.04s , +27d 44m 24.1s) |   C |    60 | 16.9 |        
   75211 | 2023-02-21 18:18:06 |         MASTER-SAAO | (03h 00m 15.42s , +25d 50m 37.4s) |   C |    60 | 17.3 |        
   75211 | 2023-02-21 18:18:06 |         MASTER-SAAO | (03h 01m 11.01s , +25d 50m 20.3s) |   C |    60 | 17.4 |        
   75291 | 2023-02-21 18:19:26 |         MASTER-SAAO | (03h 09m 01.02s , +25d 49m 35.2s) |   C |    60 | 17.5 |        
   75291 | 2023-02-21 18:19:26 |         MASTER-SAAO | (03h 09m 56.69s , +25d 49m 18.2s) |   C |    60 | 17.6 |        
   75381 | 2023-02-21 18:20:57 |         MASTER-SAAO | (02h 27m 31.68s , +25d 51m 45.2s) |   C |    60 | 16.8 |        
   75381 | 2023-02-21 18:20:57 |         MASTER-SAAO | (02h 26m 36.42s , +25d 52m 03.5s) |   C |    60 | 16.6 |        
   75461 | 2023-02-21 18:22:16 |         MASTER-SAAO | (02h 35m 26.12s , +25d 50m 31.7s) |   C |    60 | 17.0 |        
   75461 | 2023-02-21 18:22:16 |         MASTER-SAAO | (02h 36m 21.46s , +25d 50m 13.3s) |   C |    60 | 17.3 |        
   75552 | 2023-02-21 18:23:47 |         MASTER-SAAO | (02h 49m 12.43s , +29d 39m 01.5s) |   C |    60 | 17.4 |        
   75552 | 2023-02-21 18:23:47 |         MASTER-SAAO | (02h 50m 09.66s , +29d 38m 42.6s) |   C |    60 | 17.6 |        
   75631 | 2023-02-21 18:25:07 |         MASTER-SAAO | (02h 58m 22.85s , +29d 39m 58.7s) |   C |    60 | 17.6 |        
   75631 | 2023-02-21 18:25:07 |         MASTER-SAAO | (02h 59m 20.21s , +29d 39m 39.5s) |   C |    60 | 17.9 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB230217A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33363
SUBJECT: GRB 230217A: Swift-BAT refined analysis
DATE:    23/02/21 18:54:55 GMT
FROM:    Hans Krimm at NSF/NASA-GSFC  <hkrimm@nsf.gov>

S. D. Barthelmy (GSFC), H. A. Krimm (NSF), S. Laha (GSFC/UMBC),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC), M. J. Moss (GWU),
D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU),
M. Stamatikos (OSU) (i.e. the Swift-BAT team):

Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 230217A (trigger #1154967)
(Moss, et al., GCN Circ. 33339).  The BAT ground-calculated position is
RA, Dec = 280.759, -28.840 deg which is
   RA(J2000)  =  18h 43m 02.2s
   Dec(J2000) = -28d 50' 23.0"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 21%.

The mask-weighted light curve shows a double-peaked event running from
T -0.2 sec to about T+1.2 sec. T90 (15-350 keV) is 1.30 +- 0.45 sec.
(estimated error including systematics).  The T90 vs. hardness diagram shows
the burst well within the short-hard burst region.

The time-averaged spectrum from T-0.26 to T+1.75 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
0.99 +- 0.12.  The fluence in the 15-150 keV band is 2.3 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-0.24 sec in the 15-150 keV band
is 20.2 +- 1.5 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.
The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1154967/BA/


GRB_name: GRB230217A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33365
SUBJECT: GRB 230217A: Swift-XRT afterglow detection
DATE:    23/02/22 08:59:54 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

M. Capalbi (INAF-IASFPA), J.A. Kennea (PSU), A. Tohuvavohu (U.
Toronto), D.N. Burrows (PSU), K.L. Page (U. Leicester), A.P. Beardmore
(U. Leicester), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR)
and P.A. Evans (U. Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has conducted further observations of the field of the
Swift-BAT-detected burst GRB 230217A (Barthelmy et al. GCN Circ.
33363). The observations now extend from T0+45.9 ks to T0+342.9 ks. 

Of the sources reported by Capalbi et al. (GCN Circ. 33348), "Source 3"
is fading with >3-sigma significance, and is therefore likely the GRB
afterglow. Using 874 s of PC mode data and 1 UVOT image, we find an
enhanced XRT position (using the XRT-UVOT alignment and matching UVOT
field sources to the USNO-B1 catalogue): RA, Dec = 280.77002, -28.83740
which is equivalent to:

RA (J2000): 18h 43m 04.80s
Dec(J2000): -28d 50' 14.6"

with an uncertainty of 4.7 arcsec (radius, 90% confidence). This
position is 67 arcsec from the Swift-BAT position. 

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.1 (+0.6, -0.4).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.6 (+0.8, -0.4). The
best-fitting absorption column is  consistent with the Galactic value
of 1.6 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum  is 4.4 x 10^-11 (5.1 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.6 (+/-4.1) x 10^21 cm^-2
Galactic foreground: 1.6 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.6 (+0.8, -0.4)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01154967.
The results of the full analysis of the XRT observations are available
at https://www.swift.ac.uk/ToO_GRBs/01154967.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB230222A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33366
SUBJECT: GRB 230222A: Fermi GBM Final Real-time Localization
DATE:    23/02/22 09:52:14 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 09:41:49 UT on 22 Feb 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230222A (trigger 698751714.60643 / 230222404).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 292.5, Dec = -26.0 (J2000 degrees, equivalent to J2000 19h 30m, -26d 00'), with a statistical uncertainty of 11.5 degrees.

The angle from the Fermi LAT boresight is 77.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230222404/quicklook/glg_skymap_all_bn230222404.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230222404/quicklook/glg_healpix_all_bn230222404.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230222404/quicklook/glg_lc_medres34_bn230222404.gif


GRB_name: GRB230220A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33367
SUBJECT: GRB 230220A: Correction to GCN 33352
DATE:    23/02/22 11:20:31 GMT
FROM:    Hitoshi Negoro at Nihon U  <negoro.hitoshi@nihon-u.ac.jp>

S. Nawa (Chuo U.), H. Negoro, M. Nakajima, K. Kobayashi, M. Tanaka, Y. Soejima (Nihon U.), 
T. Mihara, T. Kawamuro, S. Yamada, T. Tamagawa, M. Matsuoka (RIKEN), 
T. Sakamoto, M. Serino, S. Sugita, H. Hiramatsu, H. Nishikawa, A. Yoshida (AGU), 
Y. Tsuboi, J. Kohara, S. Urabe, N. Nemoto (Chuo U.), M. Shidatsu, M. Iwasaki (Ehime U.),
N. Kawai, M. Niwano, R. Hosokawa, Y. Imai, N. Ito, Y. Takamatsu (Tokyo Tech), 
S. Nakahira,  S. Ueno, H. Tomida, M. Ishikawa,  T. Kurihara (JAXA), 
Y. Ueda, S. Ogawa, K. Setoguchi, T. Yoshitake, K. Inaba, Y. Nakatani (Kyoto U.), 
M. Yamauchi, T. Sato, R. Hatsuda, R. Fukuoka, Y. Hagiwara, Y. Umeki (Miyazaki U.), 
K. Yamaoka (Nagoya U.), Y. Kawakubo (LSU), M. Sugizaki (NAOC), and W. Iwakiri (Chiba U.)
report on behalf of the MAXI team:

Because the error box information for GRB 230220A reported in GCN #33352 was incorrect,
we correct it as follows.

The MAXI/GSC nova alert system triggered a bright uncatalogued X-ray transient source 
at 08:55:58 UT on 20  Feb 2023. Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (346.565 deg, 18.607 deg) = (23 06 15, +18 36 25) (J2000)
with a statistical 90% C.L. elliptical error region
with long and short radii of 0.22 deg and 0.19 deg, respectively.
The roll angle of long axis from the north direction is 153.0 deg counterclockwise.
Without assumptions on the source constancy, we obtain a rectangular error box 
for the transient source with the following corners.
(345.720, 19.547) deg = (23 02 52, +19 32 49) (J2000)
(345.464, 19.290) deg = (23 01 51, +19 17 23) (J2000)
(347.309, 17.634) deg = (23 09 14, +17 38 02) (J2000)
(347.566, 17.889) deg = (23 10 15, +17 53 20) (J2000)
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 182 +- 28 mCrab
(4.0-10.0keV, 1 sigma error).
There was no significant excess flux in the previous transit at 07:22 UT with an upper limit of 20 mCrab.


GRB_name: GRB230217A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33368
SUBJECT: GRB 230217A: Continued Gemini Observations
DATE:    23/02/22 16:50:07 GMT
FROM:    James Gillanders at University of Rome Tor Vergata  <jhgillanders.astro@gmail.com>

J. Gillanders (UTV), B. O'Connor (UMD, GWU) and E. Troja (UTV) report:

We performed further follow-up of the short GRB 230217A (Moss et al. GCN
33339, Svinkin et al. GCN 33349, Veres et al. GCN 33353) using the GMOS
instrument at Gemini-South. Observations were carried out in the i-band
and began at 08:55:27 on 2023-02-21, corresponding to ~3.5 d after the
GRB trigger.

Following recent XRT observations, X-ray source 3 has been confirmed to
fade with >3-sigma significance, and thus is likely the GRB afterglow
(Capalbi et al. GCN 33365). By performing image subtraction between the
two Gemini observations (see also Oâ€™Connor et al. GCN 33356, Troja et
al. GCN 33360) we find no sign of variability and place a limit of i>23
AB mag over the entire XRT error circle. 

At the position of the radio source #3 (Schroeder et al. GCN 33358), we
set an upper limit of i>24.3 AB mag at 3.5 d post-burst. This value is
not corrected for Galactic extinction.

We thank the staff of the Gemini Observatory for executing these observations.


GRB_name: GRB230216A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33369
SUBJECT: GRB 230216A: Swift/UVOT Upper Limits
DATE:    23/02/22 19:58:25 GMT
FROM:    Noel Klingler at NASA-GSFC / UMBC  <njk5441@psu.edu>

N. Klingler (GSFC/UMBC/CRESTII) reports on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 230216A 106 s
after the BAT trigger (Klingler et al., GCN Circ. 33328).  No optical
afterglow consistent with the optical position
(Gendre et al. GCN Circ. 33329) is detected in the initial UVOT exposures.
3-sigma upper limits using the UVOT photometric system (Breeveld et al.
2011, AIP Conf. Proc. 1358, 373) for the first finding chart (FC) exposure
and subsequent exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC           106          256          147         >16.9
u_FC               264          514          246         >16.9
white              106         1188          353         >16.8
v                  594         1065           58         >15.9
b                  520         1164           58         >16.5
u                  264         1139          304         >16.9
w1                 643         1114           58         >17.1
m2                 618         1090           58         >17.6
w2                 569         1213           78         >17.7

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.198 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB230217A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33370
SUBJECT: GRB 230217A: Swift/UVOT Upper Limits
DATE:    23/02/22 21:02:57 GMT
FROM:    Alexander Belles at PSU/Swift  <aub1461@psu.edu>

The Swift/UVOT began settled observations of the field of GRB 230217A
45.8 ks after the Swift/BAT trigger (Moss et al., GCN Circ. 33339).
No optical afterglow consistent with the XRT position
(Capalbi et al., GCN Circ. 33365) is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the initial exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

wh               45886        84347         2643        >21.37
u               329962       342875         4884        >20.78

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.15 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB230205A
Detection_method: VLA Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33372
SUBJECT: GRB 230205A: VLA radio afterglow confirmation
DATE:    23/02/23 21:04:20 GMT
FROM:    Genevieve Schroeder at Northwestern University  <genevieveschroeder2023@u.northwestern.edu>

G. Schroeder, (Northwestern), T. Laskar (Utah) report:

"We re-observed the position of the possibly short GRB 230205A (Ambrosi et
al., GCN 33271; Sakamoto et al., GCN 33280) with the Karl G. Jansky Very
Large Array (VLA) under program 23A-296 (PI: Schroeder) beginning on 2023
February 22.52 UT (17.08 days post-burst) at a mean frequency of 6 GHz.

The radio source detected in the previous VLA observation at 2.81 days
(Schroeder et al. GCN 33309) has brightened significantly at 6 GHz,
confirming this source as the radio afterglow of GRB 230205A. We report an
updated radio position of:

RA(J2000) = 13:28:16.837

Dec(J2000) = +46:43:33.13

With an uncertainty of ~0.1" in each coordinate.

Further observations are planned. We thank the VLA staff for quickly
approving and executing these observations."


GRB_name: GRB230216A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33373
SUBJECT: GRB 230216A Mondy Observations
DATE:    23/02/23 23:42:28 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

N. Pankov (HSE), A. Pozanenko (IKI), E. Klunko (ISTP), S. Belkin (IKI) 
report on behalf of GRB IKI FuN:

We observed  the field of Swift GRB 220306B (Klingler et al. GCN 33328) 
with AZT-33IK telescope of Mondy observatory  in  R-filter on 
2023-02-16, 2023-02-18, and 2023-02-20. We detect the optical afterglow 
of GRB 230216A (Gendre et al. GCN33329) on 2023-02-16 and do not detect 
on 2023-02-18 and 2023-02-20.
Preliminary photometry after subtraction of template image obtained on 
2023-02-20 we obtained following results

Date       UT start  t-T0     Exp.  Filter   OT     Err.  UL(3sigma)
                    (mid, days)  (s)

2023-02-16 15:18:03  0.041319 60*60 R        18.10  0.06   22.1
2023-02-18 13:39:52  1.973123 60*60 R        n/d    n/d    21.2

The photometry is based on nearby USNO-B1.0 stars.
             USNO-B1.0
             RA Dec R2
             113.9612341 -8.0016198 16.61
             113.9487699 -8.0038889 16.65
             113.9570121 -7.9997820 17.15


GRB_name: GRB230217A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33374
SUBJECT: GRB 230217A: VLT/FORS2 optical observations and candidate counterpart
DATE:    23/02/24 15:50:32 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <pda.davanzo@gmail.com>

P. D'Avanzo, A. Rossi (INAF-OAS), R. Brivio (INAF-OAB), D. B. Malesani (Radboud Univ.and DAWN/NBI), A. Saccardi (GEPI, Observatoire de Paris), 
S. Campana (INAF-OAB), B. Gompertz (Univ. Birmingham), D. Hartmann (Clemson Univ.), D. A. Kann (Goethe Univ). A. J. Levan (Radboud Univ.), 
G. Tagliaferri (INAF-OAB), N. R. Tanvir (Univ. Leicester) report on behalf of the Stargate consortium:

We observed the field of the short GRB 230217A (Moss et al. GCN Circ. 33339) with the ESO/VLT equipped with the FORS2 instrument. 
A series of optical images has been obtained with the I filter on 2023 February 20 (i.e. about 2.5 days after the burst) and on 2023 
February 23 (i.e. about 5.5 days after the burst). 

Image subtraction carried out between the two epochs shows a residual at the following position:
RA (J2000) = 18:43:04.97
Dec (J2000) = -28:50:16.4 

+/- 0.3". 

This position lies inside the XRT error circle of the X-ray afterglow position (Capalbi et al., GCN Circ. 33365) and is consistent with the 
position of the radio source reported by Schroeder et al. (GCN Circ. 33358). 

From preliminary photometry, we measure for this source a magnitude of I ~ 24.5 (AB) at t-t0 = 2.5 days.

We propose this source as a candidate optical counterpart of GRB 230217A. 

Further observations are planned.


We acknowledge excellent support from the ESO observing staff in Paranal, in particular Julia Seidel, Konrad Tristram and Thomas Rivinius.


GRB_name: GRB230227A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33376
SUBJECT: GRB 230227A: Fermi GBM Final Real-time Localization
DATE:    23/02/27 10:32:34 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 10:22:03 UT on 27 Feb 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230227A (trigger 699186128.22906 / 230227432).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 348.0, Dec = -50.4 (J2000 degrees, equivalent to J2000 23h 11m, -50d 23'), with a statistical uncertainty of 1.8 degrees.

The angle from the Fermi LAT boresight is 120.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230227432/quicklook/glg_skymap_all_bn230227432.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230227432/quicklook/glg_healpix_all_bn230227432.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230227432/quicklook/glg_lc_medres34_bn230227432.gif


GRB_name: GRB230227A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33377
SUBJECT: Fermi GRB 230227A: Global MASTER-Net observations report 
DATE:    23/02/27 20:45:23 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 230227A ( Fermi GBM team, GCN 33376) errorbox  27935 sec after notice time and 27945 sec after trigger time at 2023-02-27 18:07:48 UT, with upper limit up to  18.0 mag. Observations started at twilight.  The observations began at zenith distance = 71 deg. The sun  altitude  is -11.4 deg. 

The galactic latitude b = -61 deg., longitude l = 335 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2201434

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   27975 | 2023-02-27 18:07:48 |         MASTER-SAAO | (23h 22m 43.55s , -50d 06m 48.8s) |   C |    60 | 15.8 |        
   28055 | 2023-02-27 18:09:07 |         MASTER-SAAO | (23h 03m 26.41s , -48d 11m 15.9s) |   C |    60 | 14.7 |        
   28146 | 2023-02-27 18:10:39 |         MASTER-SAAO | (23h 15m 26.92s , -48d 13m 00.1s) |   C |    60 | 15.7 |        
   28533 | 2023-02-27 18:17:05 |         MASTER-SAAO | (22h 54m 28.18s , -51d 59m 07.3s) |   C |    60 | 16.4 |        
   28612 | 2023-02-27 18:18:25 |         MASTER-SAAO | (23h 07m 21.20s , -51d 59m 54.1s) |   C |    60 | 17.1 |        
   28703 | 2023-02-27 18:19:56 |         MASTER-SAAO | (23h 19m 03.56s , -51d 59m 04.8s) |   C |    60 | 17.4 |        
   28782 | 2023-02-27 18:21:15 |         MASTER-SAAO | (23h 32m 10.32s , -52d 00m 19.3s) |   C |    60 | 17.6 |        
   28956 | 2023-02-27 18:24:09 |         MASTER-SAAO | (22h 59m 02.16s , -50d 06m 24.6s) |   C |    60 | 17.1 |        
   29048 | 2023-02-27 18:25:40 |         MASTER-SAAO | (23h 04m 37.58s , -53d 52m 45.1s) |   C |    60 | 17.5 |        
   29138 | 2023-02-27 18:27:11 |         MASTER-SAAO | (23h 18m 13.09s , -53d 54m 42.5s) |   C |    60 | 17.8 |        
   29223 | 2023-02-27 18:28:36 |         MASTER-SAAO | (23h 10m 16.61s , -50d 05m 00.7s) |   C |    60 | 17.2 |        
   29314 | 2023-02-27 18:30:07 |         MASTER-SAAO | (23h 22m 39.71s , -50d 05m 57.9s) |   C |    60 | 17.9 |        
   29399 | 2023-02-27 18:31:32 |         MASTER-SAAO | (23h 03m 25.78s , -48d 10m 31.1s) |   C |    60 | 17.0 |        
   29489 | 2023-02-27 18:33:01 |         MASTER-SAAO | (23h 15m 32.95s , -48d 11m 45.1s) |   C |    60 | 17.5 |        
   29570 | 2023-02-27 18:34:23 |         MASTER-SAAO | (22h 54m 24.11s , -52d 00m 20.0s) |   C |    60 | 17.1 |        
   29659 | 2023-02-27 18:35:52 |         MASTER-SAAO | (23h 07m 28.96s , -52d 00m 30.7s) |   C |    60 | 17.9 |        
   29749 | 2023-02-27 18:37:22 |         MASTER-SAAO | (23h 19m 08.93s , -51d 58m 50.7s) |   C |    60 | 17.9 |        
   29829 | 2023-02-27 18:38:42 |         MASTER-SAAO | (23h 32m 09.06s , -52d 00m 48.4s) |   C |    60 | 18.0 |        
   29926 | 2023-02-27 18:40:18 |         MASTER-SAAO | (22h 58m 57.37s , -50d 05m 19.4s) |   C |    60 | 17.6 |        
   30005 | 2023-02-27 18:41:38 |         MASTER-SAAO | (23h 04m 36.55s , -53d 52m 26.0s) |   C |    60 | 18.0 |        
   30096 | 2023-02-27 18:43:09 |         MASTER-SAAO | (23h 18m 17.75s , -53d 53m 39.5s) |   C |    60 | 18.0 |        
   30175 | 2023-02-27 18:44:28 |         MASTER-SAAO | (23h 26m 21.92s , -48d 12m 46.9s) |   C |    60 | 17.9 |        
   31810 | 2023-02-27 19:11:42 |         MASTER-SAAO | (23h 35m 15.88s , -50d 04m 17.8s) |   C |    60 | 17.8 |        
   31810 | 2023-02-27 19:11:42 |         MASTER-SAAO | (23h 33m 34.02s , -50d 04m 42.6s) |   C |    60 | 17.2 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB230228A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33378
SUBJECT: GRB 230228A: Swift detection of a possibly short burst
DATE:    23/02/28 06:03:29 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

S. Dichiara (PSU), J.D. Gropp (PSU), D. M. Palmer (LANL) and
T. M. Parsotan (GSFC/UMBC/CRESSTII) report on behalf of the Neil
Gehrels Swift Observatory Team:

At 05:50:50 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 230228A (trigger=1156572).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 18.403, +44.489 which is 
   RA(J2000) = 01h 13m 37s
   Dec(J2000) = +44d 29' 19"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single symmetrical
peak structure with a duration of about 1.5 sec.  The peak count rate
was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 05:52:49.2 UT, 119.0 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 18.37776, 44.48321 which
is equivalent to:
   RA(J2000)  = 01h 13m 30.66s
   Dec(J2000) = +44d 28' 59.6"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 68 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at https://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 9.72
x 10^20 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 122 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.085. 

Burst Advocate for this burst is S. Dichiara (simonedichiara55 AT gmail.com). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)


GRB_name: GRB230228A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33379
SUBJECT: GRB 230228A: Prompt enhanced Swift-XRT position
DATE:    23/02/28 06:35:05 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:

Using  promptly downlinked XRT event data for GRB 230228A, we find an
enhanced XRT position of the afterglow: RA, Dec: 18.37804, 44.48289
which is equivalent to:
   RA (J2000)  = 01 13 30.73
   Dec (J2000) = +44 28 58.4
with an uncertainty of 1.9 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/1156572.

Position enhancement is is described by Goad et al. (2007, A&A, 476,
1401) and Evans et al. (2009, MNRAS, 397, 1177).

This circular is an official product of the Swift-XRT team.


GRB_name: GRB230228A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33380
SUBJECT: GRB 230228A: Miryang Arirang Astronomical Observatory (MAAO) 0.7-m telescope optical upper limit
DATE:    23/02/28 13:33:13 GMT
FROM:    Gu Lim at Seoul National U  <lim9gu@gmail.com>

Gu Lim (PNU), Donghyun Kim (PNU), Dohyeong Kim (PNU), Myungshin Im
(SNU ARC/SNU), Gregory S.H. Paek (SNU ARC/SNU), Keun-Hong Park (MAAO),
and Seonghun Lim (MAAO) on behalf of GECKO collaboration

We searched for the optical counterpart of a possible short burst GRB
230228A (Dichiara et al. GCN #33378) with the 0.7-m telescope at Miryang
Arirang Astronomical Observatory (MAAO), located at Miryang, Republic of
Korea. We observed the center of Swift-XRT localization (RA, Dec =
01:13:30.73, +44:28:58.4; Evans et al. GCN #33379) +4.09 hours after
report, but could not find any possible transient within the field of view
(28.2' x 28.2'). We performed flux calibration with the PS1 catalog and
used the AB magnitude system. Each depth means 3 and 5 sigma upper limit
for a point source detection. The magnitudes are not corrected for galactic
extinction.

object     exposures  date-obs (UT)       MJD        band Depth(3Ïƒ) Depth(5
Ïƒ) FWHM(")
=========================================================================================
GRB230228A 60sx8      2023-02-28T09:56:11 60003.414  V    <18.77     <18.21
     2.8

Gravitational wave Electromagnetic wave Counterpart Korean Observatory
(GECKO) is a network of 10+ 0.5m to 1m class telescopes over the world.


á§


GRB_name: GRB230228A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33381
SUBJECT: GRB 230228A: Nanshan/NEXT optical upper limit
DATE:    23/02/28 16:50:31 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

T.H. Lu, S.Q. Jiang, S.Y. Fu, X. Liu (NAOC), Z.P. Zhu (NAOC, HUST), D. 
Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:

We observed the field of GRB 230228A detected by Swift (Dichiara et al., 
GCN 33378) using the NEXT-0.6m telescope located at Nanshan, Xinjiang, 
China. We obtained 12x200 s frames in the Sloan r-band and 12x200 s 
frames in the Sloan z-band, starting at 14:37:32 UT on 2023-02-28 (i.e., 
8.77 hr after the BAT trigger).

No optical source is detected in our stacked images at the enhanced XRT 
position (Evans, GCN 33379), and preliminary photometric results are as 
follows:

T_mid-T0 (hr)    Filter   Upper limit(3-sigma)
    9.86                r          >20.6
    9.14                z          >19.5

calibrated with the nearby PanSTARRS field and not corrected for 
Galactic extinction.


GRB_name: GRB230228A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33382
SUBJECT: GRB 230228A: Enhanced Swift-XRT position
DATE:    23/02/28 17:09:14 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 2720 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 230228A, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 18.37812, +44.48293 which is equivalent
to:

RA (J2000): 01h 13m 30.75s
Dec (J2000): +44d 28' 58.5"

with an uncertainty of 2.1 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB230228A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33383
SUBJECT: GRB 230228A: Mondy optical upper limit
DATE:    23/02/28 19:12:56 GMT
FROM:    XXXX at IKI  <alex@cgrsmx.iki.rssi.ru>

S. Belkin (IKI, HSE), E. Klunko (ISTP), A. Pozanenko (IKI),  N. Pankov (HSE) report on behalf of GRB IKI FuN:

We observed the field of GRB 230228A (Dichiara et al., GCN 33378) with AZT-33 telescope of Mondy observatory starting on Feb. 28 (UT) 12:46:56. We do not detect any optical counterpart within the enhanced Swift/XRT error box (Beardmore et al., GCN 33382). Preliminary photometry of the field  is following

Date       UT start t-T0     Filter    Exp.    OT   Err  UL(3sigma)

2023-02-28 12:46:56 0.31053  R         30*120  n/d  n/d  21.1

The photometry is based on the nearby USNO-B1.0 stars R2  
RA DEC R2
01:13:35.3661600 +44:26:54.711600 15.50
01:13:18.4240800 +44:28:30.280800 16.70

The upper limit is not contradict observations reported earlier (Dichiara et al., GCN 33378; Lim et al., GCN 33380; Lu et al., GCN 33381).


GRB_name: GRB230228A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33384
SUBJECT: GRB 230228A: Swift-XRT refined Analysis
DATE:    23/03/01 01:07:58 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. Tohuvavohu (U. Toronto), D.N. Burrows (PSU), J. D. Gropp (PSU), A.P.
Beardmore (U. Leicester), P.A. Evans (U. Leicester), J.P. Osborne (U.
Leicester), M. Perri (SSDC & INAF-OAR), V. D'Elia (SSDC & INAF-OAR), B.
Sbarufatti (INAF-OAB) and S. Dichiara report on behalf of the Swift-XRT
team:

We have analysed 6.9 ks of XRT data for GRB 230228A (Dichiara et al.
GCN Circ. 33378), from 102 s to 63.7 ks after the  BAT trigger. The
data comprise 10 s in Windowed Timing (WT) mode (taken while Swift was
slewing), with the remainder in Photon Counting (PC) mode. The enhanced
XRT position for this burst was given by Beardmore et al. (GCN Circ.
33379).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.94 (+/-0.07).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.82 (+0.27, -0.25). The
best-fitting absorption column is  2.1 (+1.1, -0.9) x 10^21 cm^-2, in
excess of the Galactic value of 9.7 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.9 x 10^-11 (5.0 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.1 (+1.1, -0.9) x 10^21 cm^-2
Galactic foreground: 9.7 x 10^20 cm^-2
Excess significance: 1.9 sigma
Photon index:      1.82 (+0.27, -0.25)

If the light curve continues to decay with a power-law decay index of
0.94, the count rate at T+24 hours will be 2.1 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.1 x
10^-14 (1.0 x 10^-13) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01156572.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB230301A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33385
SUBJECT: GRB 230301A: Fermi GBM Final Real-time Localization
DATE:    23/03/01 06:50:48 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 06:40:10 UT on 1 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230301A (trigger 699345615.891978 / 230301278).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 319.1, Dec = 68.3 (J2000 degrees, equivalent to J2000 21h 16m, 68d 17'), with a statistical uncertainty of 3.0 degrees.

The angle from the Fermi LAT boresight is 15.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230301278/quicklook/glg_skymap_all_bn230301278.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230301278/quicklook/glg_healpix_all_bn230301278.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230301278/quicklook/glg_lc_medres34_bn230301278.gif


GRB_name: GRB230228A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33387
SUBJECT: GRB 230228A: OSN optical upper limit
DATE:    23/03/01 11:21:01 GMT
FROM:    Youdong HU at IAA-CSIC  <huyoudong072@hotmail.com>

Y.-D. Hu, V. Casanova, E. Fernandez-Garcia, A. J. Castro-Tirado, I. Perez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez, S. Guziy (IAA-CSIC), on behalf of a larger collaboration, report:

Following the detection of GRB 230228A by Swift (Dichiara et al. GCN 33378), we triggered the 0.9m OSN telescope in Granada (Spain) starting on Feb. 28 at 19:34:03 UT (~13.7 hrs post burst). Ten images covering the burst error region were taken in the I-band. No optical afterglow is detected in the stacked image down to I=20.2 mag. These results are in agreement with the non-detection reported by Lim et al. (GCNC 33380), Lu et al. (GCNC 33381) and Belkin et al. (GCNC 33383).

We thank the staff at OSN for their excellent support.


GRB_name: GRB230228A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33389
SUBJECT: GRB 230228A: Fermi GBM Observation
DATE:    23/03/01 16:12:06 GMT
FROM:    Cori Fletcher at USRA  <cfletcher@usra.edu>

C. Fletcher (USRA), S. Lesage (UAH) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 05:50:51 UT on 28 February 2023, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 230228A (trigger 699256256/230228244).
which was also detected by Swift BAT (S. Dichiara et al. 2023, GCN 33378).
The Fermi GBM on-ground location is consistent with the Swift BAT position.

The angle from the Fermi LAT boresight is 114 degrees.

The GBM light curve consists of a single burst with a duration (T90)
of about 2 s (10-1000 keV). The time-averaged spectrum
from T0-0.9 to T0+1.5 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -0.8 +/- 0.3 and the cutoff energy,
parameterized as Epeak, is 110 +/- 20 keV.

The event fluence (10-1000 keV) in this time interval is
(5.9 +/- 0.6)E-07 erg/cm^2. The 64-ms peak photon flux measured
starting from T0+0 s in the 10-1000 keV band is 6 +/- 1 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB230301B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33390
SUBJECT: GRB 230301B: Fermi GBM Final Real-time Localization
DATE:    23/03/01 16:39:13 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely SHORT GRB

At 16:28:43 UT on 1 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230301B (trigger 699380928.235244 / 230301687).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 66.6, Dec = -7.0 (J2000 degrees, equivalent to J2000 04h 26m, -7d 00'), with a statistical uncertainty of 9.6 degrees.

The angle from the Fermi LAT boresight is 31.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230301687/quicklook/glg_skymap_all_bn230301687.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230301687/quicklook/glg_healpix_all_bn230301687.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230301687/quicklook/glg_lc_medres34_bn230301687.gif


GRB_name: GRB230301B
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33391
SUBJECT: Fermi GRB 230301B: Global MASTER-Net observations report 
DATE:    23/03/01 18:45:27 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 230301B ( Fermi GBM team, GCN 33390) errorbox  5485 sec after notice time and 5518 sec after trigger time at 2023-03-01 18:00:41 UT, with upper limit up to  16.5 mag. Observations started at twilight.  The observations began at zenith distance = 33 deg. The sun  altitude  is -10.4 deg. 

The galactic latitude b = -35 deg., longitude l = 202 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2201848

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

    5548 | 2023-03-01 18:00:41 |         MASTER-SAAO | (04h 17m 12.02s , -08d 22m 17.7s) |   C |    60 | 16.0 |        
    5548 | 2023-03-01 18:00:41 |         MASTER-SAAO | (04h 14m 06.70s , -08d 22m 37.9s) |   C |    60 | 16.2 |        
    5628 | 2023-03-01 18:02:01 |         MASTER-SAAO | (04h 25m 11.32s , -08d 23m 13.2s) |   C |    60 | 15.1 |        
    5628 | 2023-03-01 18:02:01 |         MASTER-SAAO | (04h 24m 20.52s , -08d 23m 32.5s) |   C |    60 | 15.5 |        
    5708 | 2023-03-01 18:03:20 |         MASTER-SAAO | (04h 16m 02.76s , -06d 27m 35.7s) |   C |    60 | 15.0 |        
    5708 | 2023-03-01 18:03:20 |         MASTER-SAAO | (04h 15m 12.37s , -06d 27m 54.7s) |   C |    60 | 15.2 |        
    5798 | 2023-03-01 18:04:51 |         MASTER-SAAO | (04h 24m 06.21s , -06d 29m 00.3s) |   C |    60 | 14.8 |        
    5798 | 2023-03-01 18:04:51 |         MASTER-SAAO | (04h 23m 15.75s , -06d 29m 19.5s) |   C |    60 | 15.0 |        
    5889 | 2023-03-01 18:06:22 |         MASTER-SAAO | (04h 31m 18.06s , -06d 28m 01.1s) |   C |    60 | 15.0 |        
    5889 | 2023-03-01 18:06:22 |         MASTER-SAAO | (04h 30m 27.52s , -06d 28m 19.7s) |   C |    60 | 15.1 |        
    5969 | 2023-03-01 18:07:41 |         MASTER-SAAO | (04h 39m 22.10s , -06d 26m 58.0s) |   C |    60 | 15.7 |        
    5969 | 2023-03-01 18:07:41 |         MASTER-SAAO | (04h 38m 31.49s , -06d 27m 16.7s) |   C |    60 | 15.9 |        
    6059 | 2023-03-01 18:09:12 |         MASTER-SAAO | (04h 32m 29.23s , -08d 22m 55.6s) |   C |    60 | 16.0 |        
    6059 | 2023-03-01 18:09:12 |         MASTER-SAAO | (04h 31m 38.37s , -08d 23m 14.6s) |   C |    60 | 16.1 |        
    6139 | 2023-03-01 18:10:32 |         MASTER-SAAO | (04h 40m 39.33s , -08d 22m 40.1s) |   C |    60 | 16.1 |        
    6139 | 2023-03-01 18:10:32 |         MASTER-SAAO | (04h 39m 48.37s , -08d 22m 59.2s) |   C |    60 | 16.4 |        
    6230 | 2023-03-01 18:12:02 |         MASTER-SAAO | (04h 30m 28.83s , -04d 34m 44.1s) |   C |    60 | 15.3 |        
    6230 | 2023-03-01 18:12:02 |         MASTER-SAAO | (04h 29m 38.50s , -04d 35m 02.9s) |   C |    60 | 15.6 |        
    6309 | 2023-03-01 18:13:22 |         MASTER-SAAO | (04h 38m 33.36s , -04d 32m 52.0s) |   C |    60 | 15.4 |        
    6309 | 2023-03-01 18:13:22 |         MASTER-SAAO | (04h 37m 42.95s , -04d 33m 10.8s) |   C |    60 | 15.4 |        
    6401 | 2023-03-01 18:14:53 |         MASTER-SAAO | (04h 33m 57.41s , -10d 14m 45.2s) |   C |    60 | 16.2 |        
    6401 | 2023-03-01 18:14:53 |         MASTER-SAAO | (04h 33m 06.17s , -10d 15m 04.4s) |   C |    60 | 16.3 |        
    6492 | 2023-03-01 18:16:25 |         MASTER-SAAO | (04h 42m 10.78s , -10d 15m 42.3s) |   C |    60 | 16.3 |        
    6492 | 2023-03-01 18:16:25 |         MASTER-SAAO | (04h 41m 19.46s , -10d 16m 01.2s) |   C |    60 | 16.5 |        
    6572 | 2023-03-01 18:17:45 |         MASTER-SAAO | (04h 16m 13.41s , -08d 22m 57.4s) |   C |    60 | 15.9 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB230228A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33392
SUBJECT: GRB 230228A: Swift/UVOT Upper Limits
DATE:    23/03/02 10:15:52 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>

A. A. Breeveld (UCL-MSSL) and S. Dichiara (PSU) report on behalf of the 
Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 230228A 
122 s after the BAT trigger (Dichiara et al., GCN Circ. 33378).
No optical afterglow consistent with the enhanced XRT position 
(Beardmore et al., GCN Circ. 33382) is detected in the initial UVOT 
exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system 
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first finding 
chart (FC) exposure and subsequent exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC           122          272          147         >20.2
u_FC               335          585          246         >19.5
white              122         1706          240         >20.6
v                  665         1752           97         >18.8
b                  591         1851           88         >19.8
u                  335         1830          341         >19.7
w1                 714         1806          117         >20.0
m2                 689         1780           97         >19.7
w2                 640         1731           78         >20.1

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 0.085 in the direction of 
the burst (Schlegel et al. 1998).


GRB_name: GRB230228A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33393
SUBJECT: GRB 230228A: Swift-BAT refined analysis
DATE:    23/03/02 13:58:16 GMT
FROM:    Tyler Parsotan at UMBC/GSFC/CRESST II  <parsotat@umbc.edu>

H. A. Krimm (NSF), S. D. Barthelmy (GSFC),

S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),

C. B. Markwardt (GSFC), D. M. Palmer (LANL),

T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU),

M. Stamatikos (OSU) (i.e. the Swift-BAT team):


Using the data set from T-239 to T+963 sec from the recent telemetry
downlink,

we report further analysis of BAT GRB 230228A (trigger #1156572)

(Dichiara, et al., GCN Circ. 33378).  The BAT ground-calculated position is

RA, Dec = 18.397, 44.495 deg which is

   RA(J2000)  =  01h 13m 35.3s

   Dec(J2000) = +44d 29' 41.9"

with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).

The partial coding was 78%.


The mask-weighted light curve shows a Fast Rise Exponential Decay single
pulse.

T90 (15-350 keV) is 2.18 +- 0.40 sec (estimated error including
systematics).

The time-averaged spectrum from T-0.05 to T+2.53 sec is best fit by a simple

power-law model.  The power law index of the time-averaged spectrum is

1.66 +- 0.17.  The fluence in the 15-150 keV band is 3.6 +- 0.4 x 10^-07
erg/cm2.

The 1-sec peak photon flux measured from T+0.18 sec in the 15-150 keV band

is 3.0 +- 0.4 ph/cm2/sec.  All the quoted errors are at the 90% confidence

level.



The results of the batgrbproduct analysis are available at

http://gcn.gsfc.nasa.gov/notices_s/1156572/BA/


GRB_name: GRB230228A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33394
SUBJECT: GRB 230228A: 6 GHz VLA radio upper limit
DATE:    23/03/02 17:55:24 GMT
FROM:    Genevieve Schroeder at Northwestern University  <genevieveschroeder2023@u.northwestern.edu>

G. Schroeder (Northwestern), T. Laskar (Utah), E. Berger (Harvard) report:

"We observed the position of the possibly short GRB 230228A (Dichiara et
al. GCN 33378; Fletcher GCN 33389) with the Karl G. Jansky Very Large Array
(VLA) under program 23A-296 (PI: Schroeder) beginning on 2023 March 2.02 UT
(1.78 days post-burst) at a mean frequency of 6 GHz.

Based on preliminary analysis, we do not detect any radio emission at or
near the position of the XRT afterglow (Beardmore et al., GCN 33382) to a
3-sigma limit of 12 microJy. Additional followup is planned.

We thank the VLA staff for quickly approving and executing these
observations."


GRB_name: GRB230304A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33395
SUBJECT: GRB 230304A: Fermi GBM Final Real-time Localization
DATE:    23/03/04 06:31:10 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 06:20:54 UT on 4 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230304A (trigger 699603659.15977 / 230304265).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 29.2, Dec = 32.8 (J2000 degrees, equivalent to J2000 01h 56m, 32d 47'), with a statistical uncertainty of 1.6 degrees.

The angle from the Fermi LAT boresight is 103.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230304265/quicklook/glg_skymap_all_bn230304265.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230304265/quicklook/glg_healpix_all_bn230304265.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230304265/quicklook/glg_lc_medres34_bn230304265.gif


GRB_name: GRB230304B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33396
SUBJECT: GRB 230304B: Fermi GBM Final Real-time Localization
DATE:    23/03/04 14:46:09 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 14:35:49 UT on 4 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230304B (trigger 699633354.142652 / 230304608).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 111.7, Dec = 0.9 (J2000 degrees, equivalent to J2000 07h 26m, 0d 54'), with a statistical uncertainty of 1.0 degrees.

The angle from the Fermi LAT boresight is 28.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230304608/quicklook/glg_skymap_all_bn230304608.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230304608/quicklook/glg_healpix_all_bn230304608.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230304608/quicklook/glg_lc_medres34_bn230304608.gif


GRB_name: GRB230304C
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33397
SUBJECT: GRB 230304C: Fermi GBM Final Real-time Localization
DATE:    23/03/04 22:10:27 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 22:01:39 UT on 4 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230304C (trigger 699660104.796088 / 230304918).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 280.7, Dec = -10.8 (J2000 degrees, equivalent to J2000 18h 42m, -10d 48'), with a statistical uncertainty of 5.2 degrees.

The angle from the Fermi LAT boresight is 63.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230304918/quicklook/glg_skymap_all_bn230304918.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230304918/quicklook/glg_healpix_all_bn230304918.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230304918/quicklook/glg_lc_medres34_bn230304918.gif


GRB_name: GRB230304B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33398
SUBJECT: GRB 230304B: Detection by GRBAlpha
DATE:    23/03/05 23:21:27 GMT
FROM:    Marianna Dafcikova at Masaryk University  <500025@mail.muni.cz>

M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner
(Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak
(Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, J.-P.
Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal,  A. Povalac (Brno U.
of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo,
M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U.
of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H.
Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos
U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G.
Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi
(Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss
(Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.),
H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima
U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U.
Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.

The long-duration GRB 230304B (Fermi/GBM detection: GCN Circ. 33396;
CALET/CGBM detection: trigger no. 1361975601; INTEGRAL/SPI-ACS detection at
2023-03-04 14:35:47.510) was observed by the GRBAlpha 1U CubeSat (Pal et
al. Proc. SPIE 2020).

The detection was confirmed at the peak time 2023-03-04 14:35:49 UTC. The
T90 duration measured by GRBAlpha is 16 s and the overall significance
during T90 reaches 28 sigma.

The light curve obtained by GRBAlpha is available here:

https://grbalpha.konkoly.hu/static/share/GRB230304B_GCN.pdf

All GRBAlpha detections are listed at:
https://monoceros.physics.muni.cz/hea/GRBAlpha/

GRBAlpha, launched on 2021 March 22, is a demonstration mission for a
future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector
of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a
SiPM array, covering the energy range from ~50 keV to ~1000 keV. To
increase the duty cycle and the downlink rate, the upgrade of the on-board
data acquisition software stack is in progress. The ground segment is also
supported by the radio amateur community and it takes advantage of the
SatNOGS network for increased data downlink volume.


GRB_name: GRB230304A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33399
SUBJECT: GRB 230304A: AstroSat CZTI detection
DATE:    23/03/06 06:36:26 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

P K. Navaneeth (IUCAA), R. Gopalakrishnan (IUCAA), G. Waratkar (IITB), 
A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka 
University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report 
on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 
2021, JApA, 42, 73) showed the detection of a long GRB 230304A which was 
also detected by Fermi GBM (GCN Circ. 33395).

The source was detected in the 20-200 keV energy range. The light curve 
showed multiple peaks of emission with the strongest peak at 2023-03-04 
06:21:01.35 UTC. The measured peak count rate associated with the burst 
is 292 (+147, -18) counts/s above the background in the combined data of 
three quadrants (out of four), with a total of 577 (+223, -214) counts. 
The local mean background count rate was 325 (+4, -6) counts/s. Using 
cumulative rates, we measure a T90 of 9.73 (+3, -4) s.

It was also detected in the CsI anticoincidence (Veto) detector in the 
100-500 keV energy range. The light curve peaks at 2023-03-04 06:21:00.9 
UTC. The measured peak count rate is 927 (+77, -84) counts/s above the 
background in the combined Veto data of all quadrants, with a total of 
5710 (+511, -579) counts. The local mean background count rate was 1423 
(+5, -6) counts/s. We measure a T90 of 10.23 (+4, -2) s from the 
cumulative Veto light curve.

CZTI GRB detections are reported regularly on the payload site at 
http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led 
consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, 
and PRL. The Indian Space Research Organisation funded, managed, and 
facilitated the project.


GRB_name: GRB230304B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33400
SUBJECT: GRB 230304B: AstroSat CZTI detection
DATE:    23/03/06 06:39:48 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

P K. Navaneeth (IUCAA), R. Gopalakrishnan (IUCAA), G. Waratkar (IITB), 
A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka 
University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report 
on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 
2021, JApA, 42, 73) showed the detection of a GRB 230304B which was also 
detected by Fermi GBM (GCN Circ. 33396) and GRBAlpha (Dafcikova et al., 
GCN Circ. 33398).

The source was clearly detected in the 20-200 keV energy range. The 
light curve showed multiple peaks of emission with the strongest peak at 
2023-03-04 14:35:49.5 UTC. The measured peak count rate associated with 
the burst is 640 (+51, -54) counts/s above the background in the 
combined data of three quadrants (out of four), with a total of 4194 
(+351, -404) counts. The local mean background count rate was 319 (+3, 
-5) counts/s. Using cumulative rates, we measure a T90 of 22.11 (+3, -4) 
s.

It was also clearly detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range. The light curve peaks at 2023-03-04 
14:35:48.9 UTC. The measured peak count rate is 1900 (+90, -100) 
counts/s above the background in the combined Veto data of all 
quadrants, with a total of 12984 (+592, -623) counts. The local mean 
background count rate was 1314 (+7, -6) counts/s. We measure a T90 of 
20.5 (+2, -2) s from the cumulative Veto light curve.

CZTI GRB detections are reported regularly on the payload site at 
http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led 
consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, 
and PRL. The Indian Space Research Organisation funded, managed, and 
facilitated the project.


GRB_name: GRB230304C
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33401
SUBJECT: GRB 230304C: AstroSat CZTI detection
DATE:    23/03/06 06:43:30 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

P K. Navaneeth (IUCAA), R. Gopalakrishnan (IUCAA), G. Waratkar (IITB), 
A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka 
University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report 
on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 
2021, JApA, 42, 73) showed the detection of a GRB 230304C which was also 
detected by Fermi-GBM (Fermi GBM team, GCN Circ. 33397).

The source was clearly detected in the 20-200 keV energy range. The 
light curve peaks at 2023-03-04 22:01:39.5 UTC. The measured peak count 
rate associated with the burst is 93 (+42, -15) counts/s above the 
background in the combined data of three quadrants (out of four), with a 
total of 410 (+138, -140) counts. The local mean background count rate 
was 374 (+2, -3) counts/s. Using cumulative rates, we measure a T90 of 
9.34 (+2, -4) s.

It was also detected in the CsI anticoincidence (Veto) detector in the 
100-500 keV energy range.

CZTI GRB detections are reported regularly on the payload site at 
http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led 
consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, 
and PRL. The Indian Space Research Organisation funded, managed, and 
facilitated the project.


GRB_name: GRB230307A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33405
SUBJECT: GRB 230307A: Fermi GBM Final Real-time Localization
DATE:    23/03/07 15:54:24 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 15:44:06 UT on 7 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230307A (trigger 699896651.671248 / 230307656).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 54.1, Dec = -76.6 (J2000 degrees, equivalent to J2000 03h 36m, -76d 35'), with a statistical uncertainty of 1.0 degrees.

The angle from the Fermi LAT boresight is 142.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230307656/quicklook/glg_skymap_all_bn230307656.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230307656/quicklook/glg_healpix_all_bn230307656.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230307656/quicklook/glg_lc_medres34_bn230307656.gif


GRB_name: GRB230307A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33406
SUBJECT: GRB 230307A: GECAM detection of an extremely bright burst
DATE:    23/03/07 16:53:45 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

Shaolin Xiong, Chenwei Wang, Yue Huang, report on behalf of the GECAM team:

GECAM-B was triggered in-flight by the extremely bright long burst at 
2023-03-07T15:44:06.650 UTC (T0), which was also observed by Fermi/GBM 
(GCN 33405).

The GECAM-B ground calculated location (J2000) is:

R.A.: 28.03 [deg]
Dec.: -81.51 [deg]
Error: 1 [deg] (1-sigma, statistical only)

The systematic error of this location is estimated to be ~2 degrees. 
This GECAM location is consistent with the Fermi/GBM one within error.

The GECAM-B light curve shows a roughly FRED shape with a possible 
precursor, with a total duration of ~100 sec. The time-averaged spectrum 
analysis on the trigger alert data shows this burst has a fluence of 
about 1E-3 erg/cm2 in 20-1000 keV, which is notably high, and comparable 
to GRB 130427A.  We caution that this analysis is very preliminary. 
Refined analysis will be reported later.

Follow-up observations are encouraged.


GRB_name: GRB230307A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33407
SUBJECT: GRB 230307A: Fermi GBM detection of a very bright GRB
DATE:    23/03/07 17:10:32 GMT
FROM:    Sarah Dalessi at UAH  <sd0104@uah.edu>

S. Dalessi(UAH)
report on behalf of the Fermi GBM Team:

"At 15:44:06.67 UT on 07 March 2023, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 230307A (trigger 699896651 / 230307656).

This event is one of the brightest among the GBM detected
GRBs. Follow-up across all wavelengths is encouraged.

The on-ground calculated location, using the GBM trigger
data, is RA = 54.06, DEC = -76.61 (J2000 degrees,
equivalent to J2000 03h 36m, -76d 35'), with a statistical uncertainty
of 1 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which we have characterized as a core-plus-tail model, with 90% of
GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg
systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).

The angle from the Fermi LAT boresight at the GBM trigger time is 142.0 degrees.

A full GCN of the Fermi-GBM analysis of this event will follow in a
later GCN, once the data has become available.

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB230307A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33410
SUBJECT: Solar Orbiter STIX observation of GRB 230307A
DATE:    23/03/07 20:59:04 GMT
FROM:    Hualin Xiao at FHNW  <hualin.xiao@fhnw.ch>

Hualin Xiao, Sm Krucker on behalf of the STIX team report:


At 2023-03-07T15:44:09Z UT (Solar Orbiter onboard time), STIX detected GRB 230307A, when Solar Orbiter was 0.53 AU from the earth. The one-way light time between the earth and the Solar Orbiter was 264.46 sec.



The gamma-ray burst signal can be clearly seen in the STIX quick-look light curves in the range between 10 - 84 keV.  The GRB has a single peak and a  duration of about 40 seconds.



The STIX light curves for this GRB can be found here:

https://datacenter.stix.i4ds.net/view/plot/lightcurves?start=1678203251&span=1200


By using the light time difference information, we also estimated the possible locations of the GRB.

The result can be found here:

https://datacenter.stix.i4ds.net/pub/GRB/GRB230307A/GRB230307A_loc.png



The analysis results presented above are preliminary.  The science data will only be down-linked from the instrument in a month or two.  Detailed analysis of the event will be started after downloading the science data.


The Solar Orbiter (SolO) is a Sun-observing satellite developed by the European Space Agency, it was launched on 10th Feb. 2020.  It has a unique elliptical orbit around the sun, with distances varying from 0.3 - 1 AU. The Spectrometer Telescope for Imaging X-rays (STIX) is one of the ten instruments onboard the Solar Orbiter.  It measures X-rays emitted during solar flares in the energy range of 4  150 keV and takes X-ray images by using an indirect imaging technique, based on the Moir effect.  Its detectors consist of thirty-two pixelated CdTe detectors with a total effective area of 6 cm^2.

More information about STIX can be found on the STIX data center website:  https://datacenter.stix.i4ds.net/


GRB_name: GRB230307A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33411
SUBJECT: GRB 230307A: Fermi GBM Observation of a very bright burst
DATE:    23/03/07 22:31:41 GMT
FROM:    Sarah Dalessi at UAH  <sd0104@uah.edu>

S. Dalessi(UAH), O.J. Roberts (USRA), and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 15:44:06.67 UT on 07 March 2023, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 230307A (trigger 699896651 / 230307656). This burst
was also detected by Solar Orbiter STIX (Xiao et al. 2023, GCN 33410), and
GECAM (Xiong et al. 2023, GCN 33406). The Fermi GBM Final Real-time
Localization (GBM team 2023, GCN 33405) is consistent with the GECAM position.

The angle from the Fermi LAT boresight at the GBM trigger time is 142.0 degrees.

The GBM light curve consists of a single burst with a duration (T90)
of about 35 s (10-1000 keV). The time-averaged spectrum
from T0 to T0+148 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.07 +/- 0.01 and the cutoff energy,
parameterized as Epeak, is 936 +/- 3 keV.

The event fluence (10-1000 keV) in this time interval is
(2.951 +/- 0.004)E-03 erg/cm^2. The 1s peak photon flux measured
starting from T0+5.8 s in the 10-1000 keV band is 791 +/- 4 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB230307A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33412
SUBJECT: GRB 230307A: AGILE/MCAL detection
DATE:    23/03/07 22:40:47 GMT
FROM:    Claudio Casentini at INAF-IAPS  <claudio.casentini@inaf.it>

C. Casentini (INAF/IAPS), M. Tavani (INAF/IAPS, and Uni.Roma Tor Vergata),
C. Pittori, F. Lucarelli, F. Verrecchia (SSDC, and INAF/OAR)
A. Argan, M. Cardillo, Y. Evangelista, L. Foffano, G. Piano (INAF/IAPS),
A. Addis, L. Baroncelli, A. Bulgarelli, A. Di Piano, V. Fioretti,
G. Panebianco, N. Parmiggiani (INAF/OAS-Bologna),
F. Longo (Uni. Trieste, INFN Trieste), M. Romani (INAF/OA-Brera),
M. Marisaldi (INAF/OAS-Bologna, Bergen University), M. Pilia,
A. Trois (INAF/OA Cagliari), I. Donnarumma, E. Menegoni, A.Ursi (ASI),
A. Giuliani (INAF/IASF-Mi) and P. Tempesta (TeleSpazio),
report on behalf of the AGILE Team:

The AGILE satellite detected the long GRB 230307A at
T0 = 2023-03-07 15:44:06 (UTC), reported by Fermi/GBM (GCN #33405 and
GCN #33407), GECAM (GCN #33406) and Stix (GCN #33410).

The burst is clearly visible in the AGILE scientific ratemeters of the
MiniCALorimeter (MCAL; 0.4-100 MeV), and in all the panels of the
AntiCoincidence detectors (AC Top, 50-200 keV; AC Lat, 80-200 keV).
The event lasted about 30 s and it released a total number of 527069 counts
in the MCAL detector (above a background rate of 1154 Hz), and 920952 counts
in the AC Top detector (above a background rate of 2959 Hz).
The AGILE ratemeters light curves can be found at:
http://www.agilescienceapp.it/notices/GRB230307A_AGILE_RM_ND.png .

The event also triggered a high-time resolution MCAL data acquisition,
from T0 to T0+22 s (UTC), and released 241403 counts in the detector,
above a background rate of 510 Hz. The MCAL light curve can be found at:
http://www.agilescienceapp.it/notices/GRB230307A_082567_605288646.000000.png
.

At the T0, the event was 54 deg off-axis.
Additional analysis of AGILE data is in progress.
Automatic MCAL GRB alert Notices can be found at:
https://gcn.gsfc.nasa.gov/agile_mcal.html


GRB_name: GRB230307A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33413
SUBJECT: IPN triangulation of GRB 230307A (long/very bright)
DATE:    23/03/07 23:33:26 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin
on behalf of the HEND/Mars Odyssey team,

D. Svinkin, A. Lysenko, A. Ridnaia on behalf of the IPN,

A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,

E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT team,

and

W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr,
and A.S. Gardner on on behalf of the GRS-Odyssey GRB team,
report:

The very bright, long-duration GRB 230307A
(Fermi-GBM detection: the Fermi GBM team, GCN Circ. 33405;
Dalessi, GCN Circ. 33407; Dalessi and Roberts, GCN Circ. 33411;
GECAM detection: Xiong et al., GCN Circ. 33406;
Solar Orbiter STIX detection: Xiao and Krucker, GCN Circ. 33410;
AGILE-MCAL detection: Casentini et al., GCN Circ. 33412)
has been detected by Fermi(GBM trigger 699896651), GECAM,
INTEGRAL (SPI-ACS), Swift (BAT), Solar Orbiter (STIX), AGILE (MCAL),
and Mars-Odyssey (HEND), so far, at about 56647 s UT (15:44:07).
The burst was outside the coded field of view of the BAT.

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
  ------------------------------
   RA(2000), deg  Dec(2000), deg
  ------------------------------
  Center:
   59.233       -75.226
  Corners:
   70.905       -76.077
   38.996       -71.948
   38.440       -72.064
   73.041       -76.146
  --------------------------------
The error box area is 1.948 sq. deg, and its maximum
dimension is 9.6 deg (the minimum one is 11.6 arcmin).
The Sun distance was 100 deg.

This box may be improved.

The IPN localization is consistent with, but reduces the area of,
the Fermi-GBM final localization (GCN 33407).

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB230307_T56646/IPN


GRB_name: GRB230307A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33414
SUBJECT: GRB 230307A: possibly the second highest GRB energy fluence ever identified
DATE:    23/03/08 05:41:31 GMT
FROM:    Eric Burns at LSU  <erickayserburns@gmail.com>

E. Burns (LSU), A. Goldstein (USRA), S. Lesage (UAH), and S. Dalessi (UAH)
report on behalf of the Fermi-GBM Team.

The very bright long GRB 230307A has been detected by many prompt GRB
monitors (GCN Circ. 33405; Dalessi, GCN Circ. 33407; Dalessi and Roberts,
GCN Circ. 33411; GECAM detection: Xiong etal., GCN Circ. 33406; Solar
Orbiter STIX detection: Xiao and Krucker, GCN Circ. 33410; AGILE-MCAL
detection: Casentini et al., GCN Circ. 33412) at 15:44:07.

Fermi-GBM reports a preliminary 10-1000 keV fluence of
(2.951 +/- 0.004)E-03 erg/cm^2 (Dalessi and Roberts, GCNCirc. 33411) with
a best-fit Comptonized spectrum with Epeak = 936 +/- 3 keV and alpha
-1.07 +/- 0.01. Utilizing this spectrum, this corresponds to a bolometric
fluence of 4.56E-3 erg/cm^2, with negligible error.

For reported GRB energy fluence values, only GRB 221009A is higher.
GRB 130427A has a reported fluence of 2.83E-3 erg/cm^2, 840304 of
~2.8E-3 erg/cm^2, and 830801 of >2.0e-3erg/cm^2. Noting that these three
values have some uncertainty due to detector issues and that this initial
value for GRB 230307A is preliminary, from these base values GRB 230307A
has the second highest reported value.

Follow-up is thus strongly encouraged. The best current localization is
from the IPN, reported in GCN 33413.


GRB_name: GRB230307A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33415
SUBJECT: GRB 230307A: AstroSat CZTI detection
DATE:    23/03/08 06:17:52 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

P K. Navaneeth (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. 
Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao 
(IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat 
CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 
2021, JApA, 42, 73) showed the detection of the extremely bright long 
GRB 230307A which was also detected by Fermi-GBM (Fermi GBM team, GCN 
33405), GECAM (Xiong et al., GCN 33406), Solar Orbiter STIX (Xiao et 
al., GCN 33410), AGILE/MCAL (Casentini et al., GCN 33412) and IPN 
(Kozyrev et al., GCN 33413).

The source was clearly detected in the 20-200 keV energy range. The 
light curve showed multiple peaks of emission with the strongest peak at 
2023-03-07 15:44:10.0 UTC. The measured peak count rate associated with 
the burst is 4041 (+33, -37) counts/s above the background in the 
combined data of all quadrants, with a total of 90900 (+758, -850) 
counts. The local mean background count rate was 453 (+1, -1) counts/s. 
Using cumulative rates, we measure a T90 of 33 (+1, -1) s. In the 
preliminary analysis, we find 5484 Compton events associated with this 
event.

It was also clearly detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range. The light curve showed multiple peaks 
of emission with the strongest peak at 2023-03-07 15:44:15.17 UTC. The 
measured peak count rate is 276156 (+268, -300) counts/s above the 
background in the combined Veto data of all quadrants, with a total of 
5571313 (+4953, -6044) counts. The local mean background count rate was 
14750 (+7, -6) counts/s. We measure a T90 of 40 (+0.2, -0.2) s from the 
cumulative Veto light curve.

CZTI is built by a TIFR-led consortium of institutes across India, 
including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research 
Organisation funded, managed, and facilitated the project. CZTI GRB 
detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB230307A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33416
SUBJECT: GRB 230307A: BALROG localization (Fermi Trigger  699896651/ GRB 230307656)
DATE:    23/03/08 09:20:58 GMT
FROM:    Jochen Greiner at MPE,Garching  <jcg@mpe.mpg.de>

B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
699896651 at 15:44:06 on 07 March 2023 were fitted for spectrum
and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427;
Berlato et al. 2019, ApJ 873, 60).

The best-fit position (1 sigma statistical errors) is:
RA(2000.0) = 41.8+/-0.4 deg
Decl.(2000.0) = -71.5+/-0.1 deg
We estimate an additional systematic error of 2 deg. 

The position is in agreement with the IPN localization (GCN Circ. 33413).

We note that the determined localization is close to the Earth horizon, which could be an additional source of systematic errors. 

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB230307656/?data_version=h01

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/media/data/GRB230307656/data_files/230308_090913782213_GRB230307656_healpixSysErr_trigdat_h01.fits

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB230307656/json

                        


GRB_name: GRB230305A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33417
SUBJECT: GRB 230305A: Detection by GRBAlpha
DATE:    23/03/08 10:13:35 GMT
FROM:    Marianna Dafcikova at Masaryk University  <500025@mail.muni.cz>

M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner
(Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak
(Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, J.-P.
Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal,  A. Povalac (Brno U.
of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo,
M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U.
of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H.
Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos
U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G.
Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi
(Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss
(Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.),
H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima
U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U.
Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.

The long-duration GRB 230305A (Fermi/GBM detection: trigger no.
699716434; Konus/WIND
detection at 2023-03-05 13:40:30.093; INTEGRAL/SPI-ACS detection at
2023-03-05 13:40:30) was observed by the GRBAlpha 1U CubeSat (Pal et al.
Proc. SPIE 2020).

The detection was confirmed at the peak time 2023-03-05 13:40:31 UTC. The
T90 duration measured by GRBAlpha is 11 s and the overall significance
during T90 reaches 8.3 sigma. This event is consistent with being a long
GRB.

The light curve obtained by GRBAlpha is available here:

https://grbalpha.konkoly.hu/static/share/GRB230305A_GCN.pdf

All GRBAlpha detections are listed at:
https://monoceros.physics.muni.cz/hea/GRBAlpha/

GRBAlpha, launched on 2021 March 22, is a demonstration mission for a
future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector
of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a
SiPM array, covering the energy range from ~50 keV to ~1000 keV. To
increase the duty cycle and the downlink rate, the upgrade of the on-board
data acquisition software stack is in progress. The ground segment is also
supported by the radio amateur community and it takes advantage of the
SatNOGS network for increased data downlink volume.


GRB_name: GRB230307A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33418
SUBJECT: GRB 230307A: Detection by GRBAlpha
DATE:    23/03/08 11:23:01 GMT
FROM:    Marianna Dafcikova at Masaryk University  <500025@mail.muni.cz>

M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner
(Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak
(Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, J.-P.
Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal,  A. Povalac (Brno U.
of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo,
M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U.
of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H.
Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos
U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G.
Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi
(Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss
(Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.),
H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima
U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U.
Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.


The extremely bright long-duration GRB 230307A (Fermi/GBM detection: GCN
33405, 33407, 33411, 33414; GECAM-B detection: GCN 33406; Solar Orbiter
STIX detection: GCN 33410; AGILE/MCAL detection: GCN 33412; IPN
triangulation: GCN 33413; AstroSat detection: GCN 33415; BALROG
localization: GCN 33416) was observed by the GRBAlpha 1U CubeSat (Pal et
al. Proc. SPIE 2020).


The detection was confirmed at the peak time 2023-03-07 15:44:12 UTC. The
T90 duration measured by GRBAlpha is 25 s and the overall significance
during T90 reaches 305 sigma. GRBAlpha entered the outer Van Allen
radiation belt during the tail part of the burst.

The peak count rate detected by GRBAlpha reaches almost 10 000 counts/s,
which is nearly half of the peak count rate of 22 000 counts/s measured for
GRB221009A.


The light curve obtained by GRBAlpha is available here:
https://grbalpha.konkoly.hu/static/share/GRB230307A_GCN.pdf


All GRBAlpha detections are listed at:
https://monoceros.physics.muni.cz/hea/GRBAlpha/

GRBAlpha, launched on 2021 March 22, is a demonstration mission for a
future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector
of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a
SiPM array, covering the energy range from ~50 keV to ~1000 keV. To
increase the duty cycle and the downlink rate, the upgrade of the on-board
data acquisition software stack is in progress. The ground segment is also
supported by the radio amateur community and it takes advantage of the
SatNOGS network for increased data downlink volume.


GRB_name: GRB230307A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33419
SUBJECT: GRB 230307A: Tiled Swift observations
DATE:    23/03/08 12:57:43 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P. A. Evans (U. Leicester) reports on behalf of the Swift team:

Swift has initiated a series of observations, tiled on the sky, of the
Fermi/GBM GRB 230307A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00110

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. The probability of finding
serendipitous sources, unrelated to the Fermi/GBM event is high: any X-ray source
considered to be a probable afterglow candidate will be reported via a GCN Circular
after manual consideration.

Details of the XRT automated analysis methods are detailed in Evans et
al. (2007, A&A, 469, 379; 2009, MNRAS, 397, 1177 and 2014, ApJS, 210, 8).

This circular is an official product of the Swift-XRT team.


GRB_name: GRB230308A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33420
SUBJECT: GRB 230308A: Fermi GBM Final Real-time Localization
DATE:    23/03/08 13:42:49 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely SHORT GRB

At 13:32:27 UT on 8 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230308A (trigger 699975152.401482 / 230308564).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 94.9, Dec = 68.5 (J2000 degrees, equivalent to J2000 06h 19m, 68d 30'), with a statistical uncertainty of 1.2 degrees.

The angle from the Fermi LAT boresight is 42.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230308564/quicklook/glg_skymap_all_bn230308564.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230308564/quicklook/glg_healpix_all_bn230308564.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230308564/quicklook/glg_lc_medres34_bn230308564.gif


GRB_name: GRB230308A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33421
SUBJECT: GRB 230308A: BALROG localization (Fermi Trigger 699975152 / GRB 230308564)
DATE:    23/03/08 14:14:58 GMT
FROM:    Jochen Greiner at MPE,Garching  <jcg@mpe.mpg.de>

F. Kunzweiler, B. Biltzinger, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
699975152 at 13:32:27 on 08 March 2023 were automatically fitted for spectrum
and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427;
Berlato et al. 2019, ApJ 873, 60).

The best-fit position (1 sigma statistical errors) is:
RA(2000.0) = 104.5+/-7.6 deg
Decl.(2000.0) = 67.3+/-1.3 deg
We estimate an additional systematic error of 2 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB230308564/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB230308564/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB230308564/json

                        


GRB_name: GRB230308A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33422
SUBJECT: Fermi GRB 230308A: Global MASTER-Net observations report 
DATE:    23/03/08 14:45:25 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-Amur robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Blagoveshchensk State Pedagogical University) started inspect of the Fermi GRB 230308A ( Fermi GBM team, GCN 33420) errorbox  425 sec after notice time and 433 sec after trigger time at 2023-03-08 13:39:40 UT, with upper limit up to  13.7 mag. The observations began at zenith distance = 25 deg. The sun  altitude  is -38.2 deg. 

The galactic latitude b = 23 deg., longitude l = 146 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2202835

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

     463 | 2023-03-08 13:39:40 |         MASTER-Amur | (06h 45m 46.77s , +67d 45m 57.7s) |   C |    60 | 13.1 |        
     653 | 2023-03-08 13:42:19 |         MASTER-Amur | (06h 43m 52.37s , +68d 29m 21.6s) |   C |   120 | 13.4 |        
     802 | 2023-03-08 13:44:39 |         MASTER-Amur | (06h 43m 58.56s , +68d 29m 42.6s) |   C |   140 | 13.6 |        
     981 | 2023-03-08 13:47:18 |         MASTER-Amur | (06h 44m 00.51s , +68d 31m 15.4s) |   C |   180 | 13.7 |        
    1181 | 2023-03-08 13:50:38 |         MASTER-Amur | (06h 43m 59.72s , +68d 29m 55.5s) |   C |   180 | 13.3 |        
    1381 | 2023-03-08 13:53:58 |         MASTER-Amur | (06h 44m 02.77s , +68d 31m 44.3s) |   C |   180 | 13.0 |        
    1581 | 2023-03-08 13:57:18 |         MASTER-Amur | (06h 43m 56.37s , +68d 30m 49.1s) |   C |   180 | 13.0 |        
    1780 | 2023-03-08 14:00:37 |         MASTER-Amur | (06h 43m 57.85s , +68d 31m 51.9s) |   C |   180 | 12.9 |        
    2325 | 2023-03-08 14:10:42 |         MASTER-Amur | (06h 45m 57.98s , +67d 44m 51.0s) |   C |    60 | 12.5 |        
    2644 | 2023-03-08 14:16:01 |         MASTER-Amur | (06h 05m 57.43s , +67d 46m 12.0s) |   C |    60 | 12.0 |        
    2724 | 2023-03-08 14:17:21 |         MASTER-Amur | (06h 26m 53.34s , +67d 44m 35.3s) |   C |    60 | 12.2 |        
    2803 | 2023-03-08 14:18:40 |         MASTER-Amur | (06h 16m 37.96s , +65d 52m 26.5s) |   C |    60 | 12.5 |        
    2883 | 2023-03-08 14:20:00 |         MASTER-Amur | (06h 36m 08.13s , +65d 51m 18.8s) |   C |    60 | 13.0 |        
    2963 | 2023-03-08 14:21:20 |         MASTER-Amur | (05h 53m 35.35s , +69d 41m 13.3s) |   C |    60 | 11.9 |        
    3042 | 2023-03-08 14:22:39 |         MASTER-Amur | (06h 16m 33.34s , +69d 40m 49.4s) |   C |    60 | 12.2 |        
    3122 | 2023-03-08 14:23:59 |         MASTER-Amur | (06h 27m 12.11s , +71d 32m 52.6s) |   C |    60 | 12.0 |        
    3776 | 2023-03-08 14:34:53 |         MASTER-Amur | (06h 16m 33.48s , +65d 51m 08.9s) |   C |    60 | 12.0 |        
    3856 | 2023-03-08 14:36:13 |         MASTER-Amur | (06h 36m 15.00s , +65d 51m 27.1s) |   C |    60 | 12.6 |        
    3936 | 2023-03-08 14:37:32 |         MASTER-Amur | (05h 53m 40.42s , +69d 41m 35.5s) |   C |    60 | 12.6 |        
    4016 | 2023-03-08 14:38:52 |         MASTER-Amur | (06h 16m 33.80s , +69d 40m 05.9s) |   C |    60 | 13.2 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB230304B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33423
SUBJECT: GRB 230304B: CALET Gamma-Ray Burst Monitor detection
DATE:    23/03/08 16:07:13 GMT
FROM:    Yuta Kawakubo at Louisiana State U./CALET  <kawakubo1@lsu.edu>

K. Kobayashi (Waseda U), A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC),
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long GRB 230304B (Fermi GBM Final Real-time Localization: Fermi GBM team,
GCN Circ. 33396; AstroSat CZTI detection:  Navaneeth et al., GCN Circ 33400) 
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 14:35:45.442 UTC
on 4 March 2023
(http://cgbm.calet.jp/cgbm_trigger/flight/1361975601/index.html).
The burst signal was seen by only the SGM detector.

The burst light curve shows a multi-peaked structure that starts
at T+3.6 sec, peaks at T+4.1 sec, and ends at T+19.3 sec.
The T90 and T50 durations measured by the SGM data are 14.4 +/- 0.3 sec
and 9.5 +/- 0.3 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1361975601/

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.


GRB_name: GRB230307A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33424
SUBJECT: GRB 230307A: VZLUSAT-2 detection
DATE:    23/03/08 18:13:06 GMT
FROM:    Jakub Ripa at Masaryk University  <245487@mail.muni.cz>

J. Ripa (Masaryk U.), M. Dafcikova, A. Pal (Konkoly Observatory), N. 
Werner  (Masaryk U.), M. Ohno (Hiroshima U.),  L. Meszaros, B. Csak 
(Konkoly Observatory), H. Takahashi (Hiroshima U.), F. Munz , M. 
Topinka, F. Hroch, N. Husarikova, J.-P. Breuer (Masaryk U.), J. Hudec, 
J. Kapus, M. Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo 
(Needronix), G. Galgoczi (Wigner Research Center/Eotvos U.), N. Uchida 
(ISAS/JAXA), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. 
Hirose, H. Matake (Hiroshima U.), S. Hisadomi (Nagoya U.), Y. Ichinohe 
(Rikkyo U.), L. L. Kiss (Konkoly Observatory),  T. Mizuno (Hiroshima 
U.), K. Nakazawa (Nagoya U.), H. Odaka (Univ of Tokyo), K. Torigoe 
(Hiroshima U.), P. Svoboda, V. Daniel, J. Dudas, M. Junas, J. Gromes 
(VZLU), I. Vertat (FEL ZCU)  -- the VZLUSAT-2/GRB payload collaboration.

The extremely bright long-duration GRB 230307A (Fermi/GBM detection: GCN 
33405, 33407, 33411, 33414; GECAM-B detection: GCN 33406; Solar Orbiter 
STIX detection: GCN 33410; AGILE/MCAL detection: GCN 33412; IPN 
triangulation: GCN 33413; AstroSat detection: GCN 33415; BALROG 
localization: GCN 33416; GRBAlpha detection: GCN 33418) was detected by 
the GRB detectors on board of the VZLUSAT-2 3U CubeSat 
(https://www.vzlusat2.cz/en/).

The data acquisition was performed by GRB detector units no. 0 and no. 
1. The detection was confirmed at the peak time 2023-03-07 15:44:11 UTC. 
The T90 duration measured by VZLUSAT-2 is 28 s (34 s) and the 
significance during T90 reaches 219 sigma (213 sigma) for detector unit 
no. 0 (no. 1).

The light curves obtained by VZLUSAT-2 is available here:
https://vzlusat2.konkoly.hu/static/share/GRB230307A_GCN_VZLUSAT2.pdf

All VZLUSAT-2 detections are listed at:
https://monoceros.physics.muni.cz/hea/VZLUSAT-2/

The GRB detectors on VZLUSAT-2 are a demonstration payload for a future 
CubeSat constellation (Werner et al. Proc. SPIE 2018). Two GRB modules 
of VZLUSAT-2 are placed in a perpendicular manner and each consists of a 
75 x 75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the 
energy range from ~40 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 
January 13 from Cape Canaveral.


GRB_name: GRB230307A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33425
SUBJECT: Improved IPN localization for GRB 230307A
DATE:    23/03/08 20:16:29 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin
on behalf of the HEND/Mars Odyssey team,

D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko,
and T. Cline on behalf of the Konus-Wind team,

A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,

E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT team,

and

W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr,
and A.S. Gardner on on behalf of the GRS-Odyssey GRB team,
report:

Using the Konus-Wind data we have triangulated GRB 230307A
(GCNs 33405, 33406, 33407, 33410, 33411, 33412, 33413, 33414,
33415, 33416, 33418, 33424)
to the 3 sigma error box whose coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
    60.819 (04h 03m 17s) -75.379 (-75d 22' 43")
  Corners:
    61.075 (04h 04m 18s) -75.436 (-75d 26' 10")
    61.016 (04h 04m 04s) -75.358 (-75d 21' 29")
    60.565 (04h 02m 16s) -75.321 (-75d 19' 14")
    60.622 (04h 02m 29s) -75.399 (-75d 23' 56")
  ---------------------------------------------
The error box area is 30 sq. arcmin, and its maximum
dimension is 10 arcmin (the minimum one is 4.2 arcmin).
The Sun distance was 80 deg.

This box may be further improved.

The Swift ToO is ongoing.

An updated triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB230307_T56646/IPN


GRB_name: GRB230228A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33426
SUBJECT: GRB 230228A: VIRT Optical Upper Limit
DATE:    23/03/08 21:15:43 GMT
FROM:    Priya Gokuldass at Florida Tech  <pgokuldass2020@my.fit.edu>

 K. Noonan (UVI), N. Orange (OrangeWave Innovative Science, LLC), P.
Gokuldass (Florida Tech), D. Morris (UVI), K. Smith (UVI), R. Querrard
(UVI) report:

We observed the field of GRB 230228A (Dichiara et al., GCN 33378) with
the 0.5m Virgin Island Robotic Telescope (VIRT) at the University of
the Virgin Islands' Etelman Observatory on 02-28-2023 starting at
23:29:41 UT (T+17.5 hrs). We performed a series of exposures in the R
filter with a total exposure of 2940s. The weather conditions were
clear during the hours of observation. The GRB was positioned at a
lower altitude with an average airmass of 2.7.

We detect no new source within the enhanced XRT position error circle
(Beardmore et al., GNC 33382) consistent with other non-detections
(Lim et al., GCN 33380, Lu et al., GCN 33381, Belkin et al., GCN
33383, Hu et al., GCN 33387, and Breeveld et al., GCN 33392) and
report the following 3-sigma upper limit:

T_mid            ||Exposure     ||Filter      ||Limit
T+ 18 hrs       ||2940s          ||R            ||>20.6

The limit is estimated from comparison to nearby USNO B1 stars and is
not corrected for Galactic extinction. The VIRT is still in the
commissioning phase.

We acknowledge financial support from NASA MUREP MIRO award
80NSSC21M0001, NASA EPSCoR award 80NSSC22M0063, and NSF EiR award
1901296. R.Q. and N.B.O. also acknowledge financial support from South
Carolina Space Grant award 80NSSC20M0054. This message can be cited.


GRB_name: GRB230307A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33427
SUBJECT: Konus-Wind detection of GRB 230307A
DATE:    23/03/08 21:50:47 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, D. Frederiks, M. Ulanov, A. Tsvetkova,
A. Lysenko, A. Ridnaia, and T. Cline
on behalf of the Konus-Wind team, report:

The very intense, long-duration GRB 230307A
(Fermi-GBM detection: the Fermi GBM team, GCN Circ. 33405;
Dalessi, GCN Circ. 33407; Dalessi and Roberts, GCN Circ. 33411;
GECAM detection: Xiong et al., GCN Circ. 33406;
Solar Orbiter STIX detection: Xiao and Krucker, GCN Circ. 33410;
AGILE-MCAL detection: Casentini et al., GCN Circ. 33412;
IPN triangulation: Kozyrev et al., GCN Circ. 33413 and 33425;
AstroSat CZTI detection: Navaneeth et al., GCN Circ. 33415;
GRBAlpha detection: Dafcikova et al., GCN Circ. 33418;
VZLUSAT-2 detection: Ripa et al., GCN Circ. 33424)
triggered Konus-Wind at T0=56645.615 s UT (15:44:05.615).

The burst light curve shows a multipeaked structure
which starts at ~T0 and has a total duration of ~196 s.
The emission is seen up to ~10 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB230307_T56645/

As observed by Konus-Wind, the burst
had a fluence of 3.58(-0.08,+0.08)x10^-3 erg/cm2,
and a 64-ms peak flux, measured from T0+6.224 s,
of 6.66(-0.42,+0.46)x10^-4 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+71.424 s)
is best fit in the 530 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.60(-0.08,+0.08)
and Ep = 1000(-16,+15) keV (chi2 = 41/42 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -5.4
(chi2 = 41/41 dof).

The spectrum near the maximum count rate
(measured from T0+6.144 to T0+6.400 s)
is best fit in the 530 keV - 10 MeV range
by a power law with exponential cutoff model:
with  alpha = -0.13(-0.31,+0.35)
and Ep = 1321(-62,+60) keV (chi2 = 19/21 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -4.3
(chi2 = 19/20 dof).

The energy fluence of the burst is the second highest
(after BOAT GRB 221009A) and the energy peak flux is the 5th highest 
observed for GRBs for almost 28 years of the KW operation.
This supports the results reported in Burns et al., GCN Circ. 33414.

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.


GRB_name: GRB230307A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33428
SUBJECT: Fermi GRB 230307A: Global MASTER-Net observations report 
DATE:    23/03/08 22:20:57 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 230307A ( Fermi GBM team, GCN 33405) errorbox  1 days 7520 sec after notice time and 1 days 7572 sec after trigger time at 2023-03-08 17:50:19 UT, with upper limit up to  19.0 mag. Observations started at twilight.  The observations began at zenith distance = 46 deg. The sun  altitude  is -10.1 deg. 

The galactic latitude b = -37 deg., longitude l = 292 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2202708

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   94063 | 2023-03-08 17:50:19 |         MASTER-SAAO | (04h 06m 50.07s , -74d 51m 54.3s) |   C |   180 | 17.4 |        
   94063 | 2023-03-08 17:50:19 |         MASTER-SAAO | (04h 09m 51.53s , -74d 51m 58.1s) |   C |   180 | 17.1 |        
   94274 | 2023-03-08 17:53:51 |         MASTER-SAAO | (04h 06m 44.57s , -76d 46m 43.0s) |   C |   180 | 17.9 |        
   94274 | 2023-03-08 17:53:51 |         MASTER-SAAO | (04h 10m 11.69s , -76d 46m 46.6s) |   C |   180 | 17.7 |        
   94909 | 2023-03-08 18:04:25 |         MASTER-SAAO | (03h 08m 23.27s , -74d 51m 18.2s) |   C |   180 | 18.5 |        
   94909 | 2023-03-08 18:04:25 |         MASTER-SAAO | (03h 11m 26.50s , -74d 51m 25.8s) |   C |   180 | 18.5 |        
   95120 | 2023-03-08 18:07:56 |         MASTER-SAAO | (04h 06m 35.42s , -76d 44m 20.5s) |   C |   180 | 19.0 |        
   95120 | 2023-03-08 18:07:56 |         MASTER-SAAO | (04h 10m 04.25s , -76d 44m 25.9s) |   C |   180 | 18.8 |        
   95754 | 2023-03-08 18:18:31 |         MASTER-SAAO | (03h 08m 25.33s , -74d 51m 41.6s) |   C |   180 | 18.7 |        
   95754 | 2023-03-08 18:18:31 |         MASTER-SAAO | (03h 11m 30.09s , -74d 51m 50.8s) |   C |   180 | 18.7 |        
  106819 | 2023-03-08 21:23:55 |         MASTER-SAAO | (03h 03m 53.63s , -76d 38m 21.4s) |   C |    60 | 18.5 |        
  106819 | 2023-03-08 21:23:55 |         MASTER-SAAO | (03h 00m 21.60s , -76d 38m 10.8s) |   C |    60 | 18.6 |        
  107112 | 2023-03-08 21:28:48 |         MASTER-SAAO | (03h 38m 39.03s , -76d 38m 02.4s) |   C |    60 | 18.5 |        
  107112 | 2023-03-08 21:28:48 |         MASTER-SAAO | (03h 35m 05.28s , -76d 37m 50.0s) |   C |    60 | 18.5 |        
  107204 | 2023-03-08 21:30:20 |         MASTER-SAAO | (03h 34m 06.25s , -78d 31m 42.8s) |   C |    60 | 18.4 |        
  107204 | 2023-03-08 21:30:20 |         MASTER-SAAO | (03h 29m 57.72s , -78d 31m 30.2s) |   C |    60 | 18.4 |        
  107284 | 2023-03-08 21:31:41 |         MASTER-SAAO | (04h 14m 36.07s , -78d 32m 15.3s) |   C |    60 | 18.5 |        
  107284 | 2023-03-08 21:31:41 |         MASTER-SAAO | (04h 10m 26.79s , -78d 32m 04.8s) |   C |    60 | 18.5 |        
  107714 | 2023-03-08 21:37:50 |         MASTER-SAAO | (03h 39m 18.35s , -76d 34m 01.4s) |   C |   180 | 18.9 |        
  107714 | 2023-03-08 21:37:50 |         MASTER-SAAO | (03h 35m 45.53s , -76d 33m 46.1s) |   C |   180 | 19.0 |        
  107926 | 2023-03-08 21:41:22 |         MASTER-SAAO | (03h 24m 25.90s , -76d 32m 40.7s) |   C |   180 | 18.7 |        
  107926 | 2023-03-08 21:41:22 |         MASTER-SAAO | (03h 20m 53.73s , -76d 32m 24.2s) |   C |   180 | 18.9 |        
  108138 | 2023-03-08 21:44:54 |         MASTER-SAAO | (03h 24m 23.20s , -76d 33m 24.5s) |   C |   180 | 18.7 |        
  108138 | 2023-03-08 21:44:54 |         MASTER-SAAO | (03h 20m 50.60s , -76d 33m 07.7s) |   C |   180 | 18.8 |        
  108349 | 2023-03-08 21:48:25 |         MASTER-SAAO | (03h 39m 21.23s , -76d 32m 07.5s) |   C |   180 | 18.7 |        
  108349 | 2023-03-08 21:48:25 |         MASTER-SAAO | (03h 35m 48.38s , -76d 31m 51.0s) |   C |   180 | 18.9 |        
  108559 | 2023-03-08 21:51:55 |         MASTER-SAAO | (03h 39m 29.26s , -76d 33m 05.1s) |   C |   180 | 18.7 |        
  108559 | 2023-03-08 21:51:56 |         MASTER-SAAO | (03h 35m 56.14s , -76d 32m 48.9s) |   C |   180 | 18.9 |        
  108771 | 2023-03-08 21:55:27 |         MASTER-SAAO | (03h 38m 53.42s , -74d 34m 06.9s) |   C |   180 | 18.6 |        
  108771 | 2023-03-08 21:55:27 |         MASTER-SAAO | (03h 35m 47.35s , -74d 33m 50.3s) |   C |   180 | 18.8 |        
  108982 | 2023-03-08 21:58:58 |         MASTER-SAAO | (03h 35m 55.42s , -74d 33m 24.8s) |   C |   180 | 18.6 |        
  108982 | 2023-03-08 21:58:58 |         MASTER-SAAO | (03h 39m 01.23s , -74d 33m 41.8s) |   C |   180 | 18.5 |        
  109194 | 2023-03-08 22:02:30 |         MASTER-SAAO | (03h 39m 51.43s , -77d 32m 08.3s) |   C |   180 | 18.6 |        
  109194 | 2023-03-08 22:02:30 |         MASTER-SAAO | (03h 36m 01.98s , -77d 31m 51.5s) |   C |   180 | 18.8 |        
  109405 | 2023-03-08 22:06:01 |         MASTER-SAAO | (03h 36m 04.38s , -77d 33m 31.5s) |   C |   180 | 18.8 |        
  109405 | 2023-03-08 22:06:01 |         MASTER-SAAO | (03h 39m 54.39s , -77d 33m 48.0s) |   C |   180 | 18.7 |        
  109617 | 2023-03-08 22:09:33 |         MASTER-SAAO | (03h 49m 04.44s , -77d 31m 38.2s) |   C |   180 | 18.7 |        
  109617 | 2023-03-08 22:09:33 |         MASTER-SAAO | (03h 52m 54.28s , -77d 31m 54.1s) |   C |   180 | 18.7 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB230307A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33429
SUBJECT: GRB 230307A: Swift-XRT observations
DATE:    23/03/08 23:17:17 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

D.N. Burrows (PSU), J. D. Gropp (PSU), J.P. Osborne (U. Leicester),
K.L. Page (U. Leicester), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti
(INAF-OAB), A. D'Ai (INAF-IASFPA), S. Dichiara (PSU) and P.A. Evans (U.
Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the
Fermi/GBM-detected burst GRB 230307A (Dalessi et al. GCN Circ. 33407)
in a series of observations tiled on the sky. The total exposure time
is 8.6 ks, distributed over 32 tiles; the maximum exposure at a single
sky location was 1.6 ks. The data were collected between T0+76.4 ks and
T0+100.9 ks, and are entirely in Photon Counting (PC) mode. 

Two X-ray sources have been detected within the improved IPN error box
(Kozyrev et al., GCN Circ. 33425), that has been fully covered by
Swift/XRT observations.


Source 2:
   RA (J2000): 04h 03m 26.24s = 60.85935Â°
   Dec (J2000): -75Â° 22â€² 43.8â€³ = -75.3788Â°
   Error: 3.4â€³ (radius, 90% conf., enhanced)
   Count-rate: 0.019 (Â±0.004) ct s-1
   Distance: 36.6 arcsec from IPN position

Source 3:
   RA (J2000): 04h 03m 57.93s = 60.99137Â°
   Dec (J2000): -75Â° 21â€² 26.8â€³ = -75.3574Â°
   Error: 7.1â€³ (radius, 90% conf.)
   Count-rate: 2.6 (+1.9, -1.3) Ã—10-3 ct s-1
   Distance: 175 arcsec from IPN position


Source 2 is below the RASS limit and shows no definitive signs of
fading. Therefore, at the present time we cannot confirm this as the
afterglow. Source 3 is at a position consistent with a QSO candidate
(Wu et al., 2023, RAA, 23, 025006) and therefore is likely unrelated to
GRB 230307A. Further observations are ongoing. 


The results of the XRT-team automatic analysis of the tiled XRT
observations, including a position-specific upper limit calculator, are
available at https://www.swift.ac.uk/xrt_products/TILED_GRB00110. 

This circular is an official product of the Swift-XRT team.


GRB_name: GRB230307A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33430
SUBJECT: GRB 230307A: Upper limits from a neutrino search with IceCube
DATE:    23/03/09 00:17:46 GMT
FROM:    Jessie Thwaites at IceCube/U Wisc-Madison  <thwaites@wisc.edu>

The IceCube Collaboration (http://icecube.wisc.edu/) reports:


IceCube has performed a search for track-like muon neutrino events arriving from the direction of GRB 230307A (GCN 33405<https://gcn.gsfc.nasa.gov/gcn/gcn3/33405.gcn3> (Fermi-GBM)) in a  time range of -1 hour/+2 hours from the initial trigger reported by Fermi-GBM (2023-03-07 15:44:06.67 UTC), using the localization area reported by IPN (GCN 33425<https://gcn.gsfc.nasa.gov/gcn/gcn3/33425.gcn3>), during which IceCube was collecting good quality data. Zero track-like events are found coincident with the position of the GRB. We accordingly derive a time-integrated muon-neutrino flux upper limit for this source of E^2 dN/ dE = 1.0 GeV cm^-2 at 90% CL, under the assumption of an E^-2 power law. 90% of events IceCube would detect from a source at this declination with an E^-2 spectrum have energies in the approximate energy range between 90 TeV and 20 PeV.


A subsequent search was performed including 2 days of data centered on the Fermi-GBM trigger (2023-03-06 15:44:06.67 UTC to 2023-03-08 15:44:06.67 UTC). In this case, we report a p-value of 1.0, consistent with background expectation. We accordingly derive a time-integrated muon-neutrino flux upper limit for this source of E^2 dN/ dE = 1.1 GeV cm^-2 at 90% CL, under the assumption of an E^-2 power law.


The IceCube Neutrino Observatory is a cubic-kilometer neutrino detector operating at the geographic South Pole, Antarctica. The IceCube realtime alert point of contact can be reached at roc@icecube.wisc.edu<mailto:roc@icecube.wisc.edu>.


[1] IceCube Collaboration, R. Abbasi  et al., ApJ 910 4 (2021)


GRB_name: GRB230307A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33431
SUBJECT: GRB 230307A: Swift/BAT upper limits on the early afterglow
DATE:    23/03/09 01:49:22 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>

Aaron Tohuvavohu (U Toronto), Jimmy DeLaunay (U Alabama), Samuele Ronchini
(Penn State), Tyler Parsotan (GSFC/UMBC), Chris Matzner (U Toronto) report:

The extremely bright GRB 230307A (GCN 33425) was detected in prompt
emission by Swift/BAT outside the coded field of view, as reported
previously.

Soon after, a pre-planned observation serendipitously landed the GRB
position near the center of the BAT field of view, with settled
observations beginning at T0+910s. Using the BAT survey mode data, 300s
duration 80-channel Detector Plane Histograms, we search for any detection
of continued emission or bright afterglow from the burst between 910 to
1210 seconds after the burst.

No emission is detected at the IPN position of the GRB, with a 5 sigma
upper limit of 0.00656 mask-weighted counts/s (15-50 keV).
Assuming an afterglow spectrum that can be described as a power law with
photon index of 2.08 (as found for the BAT afterglow detection in GRB
221009A, Williams et al. 2023), this corresponds to an upper limit of
2.389e-9 erg/cm^2/s (15-50 keV).

This constrains GRB 230307A's early afterglow (at T0+1 ks) to be at least
~1.5 orders of magnitude fainter than that of GRB 221009A at comparable
times.


GRB_name: GRB230217A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33433
SUBJECT: GRB 230217A: ATCA rapid-response radio detection
DATE:    23/03/09 07:49:56 GMT
FROM:    Gemma Anderson at Curtin U  <gemma.anderson@curtin.edu.au>

G. E. Anderson (Curtin), J. Stevens (CSIRO), M. E. Bell (UNewcastle), T. D. Russell (INAF),
P. J. Hancock (Curtin), J. C. A. Miller-Jones (Curtin), A. Bahramian (Curtin),
A. J. van der Horst (GWU), S. D. Ryder (Macquarie), A. Rowlinson (UvA, ASTRON),
R. A. M. J. Wijers (UvA)

The Australia Telescope Compact Array (ATCA) automatically triggered on
the Swift-BAT detection of the short GRB 230217A (Moss et al., GCN 33339)
at 5.5 and 9 GHz using the rapid-response mode under program C3204
(PI: Anderson). ATCA was on target observing GRB 230217A at 22:20:19.9 UT,
just 27 minutes post-burst (Moss et al., GCN 33339) and observed for 7 hours.
At the position of the proposed X-ray (Capalbi et al., GCN 33348, GCN 33365),
radio (Schroeder et al., GCN 33358) and optical (Dâ€™Avanzo et al., GCN 33374)
counterpart, we detected a source at both 5.5 GHz and 9 GHz with flux densities
of 170 +/- 30 and 150 +/- 20 microJy/beam, respectively.
Further observations have been taken.

We thank the ATCA and the CSIRO Space and Astronomy staff for supporting
and maintaining the ATCA rapid-response observing mode.


GRB_name: GRB230307A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33434
SUBJECT: GRB 230307A: optical upper limit
DATE:    23/03/09 09:51:32 GMT
FROM:    Alberto J. Castro-Tirado at IAA-CSIC  <ajct@iaa.es>

I. PÃ©rez-GarcÃ­a (IAA-CSIC Granada, Spain), A. Maury (Space Obs, Chile), 
E. FernÃ¡ndez-GarcÃ­a, Y.-D. Hu and A. J. Castro-Tirado (IAA-CSIC and 
UMA), on behalf of a larger collaboration, report:

â€œFollowing the detection of the very bright GRB 230307A (Burns et al. 
GCNC 33414) by Fermi/GBM (the Fermi GBM team, GCNC 33405; Dalessi, GCNC 
33407; Dalessi and Roberts, GCNC 33411), GECAM (Xiong et al., GCNC 
33406), Solar Orbiter/STIX (Xiao and Krucker, GCNC 33410), AGILE/MCAL 
(Casentini et al., GCNC. 33412), INTEGRAL/SPI-ACS, Mars-Odyssey/HEND 
(Kozyrev et al. GCNC 33413), AstroSat/CZTI (Navaneeth et al. GCNC 
33415), GRBAlpha (Dafcikova et al. GCNC 33418), VZLUSAT-2 (Ripa et al. 
GCNC 33424), Konus-WIND (Svinkin et al. GCNC 33427) and Swift-BAT 
(Tohuvavohu, GCNC 33431), we observed 60% of the preliminary IPN error 
box (Kozyrev et al. GCNC 33413) with a 0.5m wide-field telescope in the 
vicinity of the BOOTES-7 astronomical station at San Pedro de Atacama 
Space Observatory. No optical candidate down to 17.4 mag is found on the 
images (clear filter, 1.6h co-add) starting at 4:36 on Mar 8 UT (i.e. 
12.9 h postburst) within the entire improved IPN position (Kozyrev et 
al. GCNC 33425).â€

This message can be quoted.


GRB_name: GRB230308A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33435
SUBJECT: GRB 230308A: AGILE/MCAL detection
DATE:    23/03/09 10:09:30 GMT
FROM:    Claudio Casentini at INAF-IAPS  <claudio.casentini@inaf.it>

C. Casentini (INAF/IAPS), F. Verrecchia (SSDC, and INAF/OAR),
M. Tavani (INAF/IAPS and Uni. Roma Tor Vergata), C. Pittori,
F. Lucarelli, F. Verrecchia (SSDC, and INAF/OAR), A. Argan,
M. Cardillo, Y. Evangelista, L. Foffano, G. Piano (INAF/IAPS),
A. Addis, L. Baroncelli, A. Bulgarelli, A. Di Piano, V. Fioretti,
G. Panebianco, N. Parmiggiani (INAF/OAS-Bologna), M. Romani
(INAF/OA-Brera), M. Marisaldi (INAF/OAS-Bologna, Bergen University),
M. Pilia, A. Trois (INAF/OA Cagliari), I. Donnarumma, E. Menegoni,
A.Ursi (ASI), A. Giuliani (INAF/IASF-Mi) and P. Tempesta (TeleSpazio),
report on behalf of the AGILE Team:

The AGILE satellite detected the short GRB 2300308A at
T0 = 2023-03-08 13:32:27.400 (UTC), reported by Fermi/GBM (GCN #33420) and
BALROG (GCN #33421).

The burst is clearly visible in the AGILE scientific ratemeters of the
MiniCALorimeter (MCAL; 0.4-100 MeV), and in all the panels of the
AntiCoincidence detectors (AC Top, 50-200 keV, ACLat, 80-200 keV).
The event lasted about 1 s and it released a total number of 1166 counts
in the MCAL detector (above a background rate of 576 Hz), and 7526 counts
in the AC Top detector (above a background rate of 3445 Hz).
The AGILE ratemeters light curves can be found at:
http://www.agilescienceapp.it/notices/GRB230308A_AGILE_RM_ND.png .

The event also triggered a high-time resolution MCAL data acquisition,
from T0 to T0+12 s (UTC), and released 1484 counts in the detector,
above a background rate of 590 Hz. The MCAL light curve can be found at:
http://www.agilescienceapp.it/notices/GRB230308A_082579_605367147.400000.png
.

At the T0 the event was 133 deg off-axis. Additional analysis of AGILE data
is in progress. Automatic MCAL GRB alert Notices can be found at:
https://gcn.gsfc.nasa.gov/agile_mcal.html


GRB_name: GRB230228A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33436
SUBJECT: GRB 230228A: NUTTelA-TAO / BSTI Optical Limits 
DATE:    23/03/09 12:17:48 GMT
FROM:    Toktarkhan Komesh at Nazarbayev University  <toktarkhan.komesh@nu.edu.kz>

T. Komesh (NU), Zh. Maksut (NU), B. Grossan (UCB, NU), Zh. Abdullayev (NU), M. Krugov (FAI), report on behalf of the Energetic Cosmos Laboratory:

The Nazarbayev University Transient Telescope at Assy-Turgen Astrophysical Observatory (NUTTelA-TAO) observed the field of GRB 230228A, observing in Sloan g', r' and i' bands, with the Burst Simultaneous Three-Channel Imager (BSTI; Grossan, Kumar & Smoot 2019, JHEA, 32, 14).

We obtained 10x300 s frames starting at UT 2023-02-28 14:03:02, 8.2 hours after the BAT trigger. Observations were made under clear conditions, beginning with the target at an altitude of 45 deg. No new or changing sources consistent with the XRT position (Evans 2023, GCN 33379) were detected. Note that these observations provide essentially full-time coverage, simultaneous in all three bands. We report the following results:

start time   t-t0(h)     end time      UL g'    UL r'  ULi'   exposure_time (s)
------------    -----       -----------       ------    ------     -----      ------
14:03:02     8.2      14:53:02        19.9    19.6    19.5 300


start time is in UT. t-t0(h) gives the time since trigger, in hours. UL gives the 5 sigma upper limit sensitivity in magnitudes for images with individual exposure times. The given upper limit values are derived from the average calibration with only 3 standard stars per frame, and no other analysis or corrections.

----------------------------------
NU = Nazarbayev University, Nur-Sultan, Kazakhstan
UCB = University of California, Berkeley, USA
FAI = Fesenkov Astrophysical Institute, Kazakhstan

This research has been funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Grant No. AP14870504). The NUTTelA-TAO Team acknowledges the support of the staff of the Assy-Turgen Astrophysical Observatory, Almaty, Kazakhstan, and the Fesenkov Astrophysical Institute, Almaty, Kazkhstan.


GRB_name: GRB230307A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33437
SUBJECT: GRB 230307A: AstroSat LAXPC detection
DATE:    23/03/09 13:15:29 GMT
FROM:    Tilak Katoch at TIFR  <tilak@tifr.res.in>

Tilak Katoch, H. M. Antia and Parag Shah TIFR, Mumbai, India.

Analysis of AstroSat LAXPC data showed the clear detection of a long GRB 
230307A. The lightcurve shows the multiple burst profile with the peak 
triggered at T0 = 15h 44m 03s UT on 07 Mar 2023. The satellite was in a 
normal operating mode and well before the entry into the SAA region.

The lightcurve has a burst profile with T90 = 36 sec. The strongest peak 
measured have a count rate above the background with 13321 +/- 117 
count/sec in LAXPC10 and 4415 +/- 68 count/sec in LAXPC20 at T0+7 sec.

Both LAXPC instruments (LAXPC10 and LAXPC20) have registered this burst 
profile in the light curve. For LAXPC20, the nominal energy range is 
3-100 keV, but due to the lower gain in LAXPC10 the energy range is 
about 30-400 keV.

The background subtracted lightcurve with 1 sec time-bin is available at 
the website:

https://www.tifr.res.in/~astrosat_laxpc/grb230307alc.jpg [1]

LAXPC was built by TIFR in collaboration with the Indian Space Research 
Organisation. The Indian Space Research Organisation funded, managed and 
facilitated the project.



Links:
------
[1] https://www.tifr.res.in/~astrosat_laxpc/grb230106lc.jpg


GRB_name: GRB230307A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33438
SUBJECT: GRB 230307A: ASO-S/HXI detection
DATE:    23/03/09 14:33:56 GMT
FROM:    Tianrui Sun at Purple Mountain Obs,CAS  <trsun@pmo.ac.cn>

Zhentong Li, Yang Su on behalf of the HXI team report:

At 2023-03 07 15:44:09 UT, HXI detected the bright GRB 230307A  (Burns et al. GCNC 33414) which was also reported by Fermi/GBM (Fermi GBM Team et al.  GCNC 33405; Dalessi, GCNC 33407; Dalessi et al. , GCNC 33411;  Dalessi et al. GCNC 33411),  GECAM (Xiong et al. GCNC 33406), STIX (Xiao et al. GCNC 33410), AGILE/MCAL (Claudio et al. GCNC 33412), IPN (Kozyrev et al. GCNC 33413, Kozyrev et al. GCNC 33425),  AstroSat CZTI (Gaurav et al. GCNC 33415),  BARLOG (Jochen et al. GCNC 33416),  GRBAlpha (Marianna et al. GCNC 33418), VZLUSAT-2 (Ripa et al. GCNC 33424),  Konus-WIND (Svinkin et al. GCNC 33427),  Swift (Phil et al. GCNC 33419, GCNC 33431),  IceCube (Jessie et al. GCNC 33430) and BOOTES (Alberto et al. GCNC 33434). 

The GRB signal is spiky with significant responses at energies from ~20 keV to the detection upper limit 300 keV of the HXI scintillation detectors. The signal displays a major peak (> 570 cts/s/detetor) and a faint secondary peak (> 230 cts/s/detetor, with an in-orbit background of ~130 cts/s/detetor). The duration of the major peak is ~16 s and the whole signal lasts for ~40 s. The time resolution of the observed signal is 4 s. The burst mode (res. as high as 0.125s) was not triggered because the GRB was detected by both total flux monitor and background monitor.

By examining the count rate distribution of the 99 detectors of HXI, the direction of the GRB was roughly deduced. Hard X-ray Imager (HXI) is one of the three scientific payloads onboard the Advanced Space-based Solar Observatory (ASO-S) satellite, which is Chinaâ€™s first comprehensive solar dedicated space science mission. HXI is designed to investigate the non-thermal high-energy electrons accelerated in solar flares by providing X-ray spectra and images of solar flaring regions in the energy range from 15 to 300 keV.  It started to work on  2022-Oct-17 and is currently in the inflight testing phase. The science data will be completely open to the community after the testing phase, i.e., around mid-April 2023.

More information about HXI can be found on the ASO-S website: http://aso-s.pmo.ac.cn/en_index.jsp


GRB_name: GRB230307A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33439
SUBJECT: GRB 230307A: Possible optical afterglow
DATE:    23/03/09 15:14:27 GMT
FROM:    Andrew Levan at U.of Leicester  <a.levan@astro.ru.nl>

A.J. Levan (Radboud), B. Gompertz (U. Birmingham), K. Ackley (U. Warwick), M. Kennedy (University College Cork), V. Dhillon (U. Sheffield) report on behalf of a larger collaboration:

"We observed the IPN localisation (Kozyrev et al. GCN 33425)  of GRB 230307A (GBM team GCN 33405, Xiong et al. GCN 33406) with ULTRACAM, mounted on the NTT at La Silla. A total of 200s of exposure (10 x 20s) were obtain simultaneously in the u, g and r filters starting at 01:58:33 UTC approximately 34.3 hours post burst.  Observations covered the entirety of the refined IPN localisation. A comparison of the observation with DSS and legacy survey image reveals a weak new optical source at a location of 

RA(J2000): 04:03:25.83
DEC(J2000): -75:22:42.7
 (+/- 0.5â€)

The source has an r-band magnitude of approximately r=20.5 at the time of these observations. We note that the source is co-incident (1.9â€ offset) with source 2 identified by the Swift-XRT (Evans, GCN 33419). Combined with the absence of the source in pre-imaging we suggest that this is the afterglow of GRB 230307A. 

We note that the source has a modest offset (3â€)  from a very red source identified in the legacy survey and WISE. It is possible that this is host galaxy of the GRB. Spectroscopic observations to obtain the redshift of both afterglow and nearby source are encouraged. "


GRB_name: GRB230308A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33440
SUBJECT: GRB 230308A: Fermi GBM detection
DATE:    23/03/09 15:35:20 GMT
FROM:    Oliver J Roberts at USRA/NASA  <oliver.roberts@nasa.gov>

C. Malacaria (ISSI) reports on behalf of the Fermi GBM Team:

"At 13:32:27.40 UT on 8 March 2023, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 230308A (trigger 699975152 / 230308564).
The Fermi GBM Final Real-time Localization was reported in GCN 33420.

The angle from the Fermi LAT boresight at the GBM trigger time is 42 degrees.

The GBM light curve consists of a slightly structured main peak
with a duration (T90) of about 0.6 s (50-300 keV).
The time-averaged spectrum from T0-0.064 s to T0+0.64 s
is best fit by a power law function with an exponential high-energy cutoff.
The power law index is -0.52 +/- 0.03 and the cutoff energy,
parameterized as Epeak, is 943 +/- 46 keV.

A Band function fits the spectrum equally well
with Epeak= 907 +/- 52 keV, alpha = -0.51 +/- 0.03,
beta = -3.1 +/- 0.4 .

The event fluence (10-1000 keV) in this time interval is
(8.5 +/- 0.2)E-06  erg/cm^2. The 0.064-sec peak photon flux measured
starting from T0 in the 10-1000 keV band
is 72 +/- 2 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB230204B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33441
SUBJECT: GRB 230204B: MASTER detection of an object near NTT  Optical Afterglow Candidate    
DATE:    23/03/09 17:24:15 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V.Lipunov (Lomonosov MSU), D.A.H.Buckley (SAAO), A.Chasovnikov, Ya.Kechin, 
A.Kuznetsov, N.Tiurina, O.Gress, E.Gorbovskoy, G.Antipov, P.Balanutsa, 
K.Zhirkov, D.Vlasenko, V.Senik, D.Kuvshinov,
V.Topolev, Yu.Tselik, D.Cheryasov, I.Gorbunov, Ya.Kechin (Lomonosov Moscow 
State University, SAI, Physics Department);
C.Francile, R. Podesta, F. Podesta (Observatorio Astronomico Felix Aguilar of 
San Juan National University of Argentina),
R. Rebolo, M. Serra (The Instituto de Astrofisica de Canarias),
L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, 
A.Corella,L.H.Rodriguez (INAOE, Guillermo Haro Astrophysics Observatory),
N.M.Budnev (ISU,API),
A. Tlatov, D. Dormidontov (Kislovodsk Solar Station of the Pulkovo 
Observatory),
A. Gabovich, V.Yurkov (Blagoveschensk Educational State University)


MASTER-SAAO robotic telescope  (Global MASTER-Net http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, v.2010, 30L)
center (Kozyrev et al.  GCN 33425) at position  Levan et al., GCN 33439 
31 hours after  trigger (22 30 43UT 1800 sec) ~20.2 (Unfiltered). The 
position accuracity 
is about ~ 1 pix =2".

But there is the Gaia star 3".3 offset with same magnitude.


No object in MPC.
The reduction will be continued.


GRB_name: GRB230307A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33442
SUBJECT: GRB 230307A: Erratum of the GCN 33441
DATE:    23/03/09 17:33:43 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V.Lipunov (Lomonosov MSU)

I am sorry for my mistake in Subject.
Correct subject is
GRB 230307A: MASTER detection of an object near NTT Optical Afterglow Candidate


GRB_name: GRB230307A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33443
SUBJECT: GRB 230307A: ATLAS information on the ULTRACAM optical afterglow candidate 
DATE:    23/03/09 18:19:09 GMT
FROM:    Stephen Smartt at Queen's U/Belfast  <s.smartt@qub.ac.uk>

M. D. Fulton, K. W. Smith, S. Srivastav, D. R. Young, M. Nicholl, M.
McCollum, T. Moore, J. Weston (QUB), S. J. Smartt (Oxford/QUB), L.
Shingles (GSI/QUB), J. Sommer (LMU/QUB), L. Rhodes (Oxford), L.
Denneau, J. Tonry, H. Weiland, A. Lawrence, R. Siverd (IfA, University
of Hawaii), N. Erasmus, W. Koorts (South African Astronomical
Observatory), A. Jordan, V. Suc (UAI, Obstech), A. Rest (STScI), T.-W.
Chen (TUM/MPA), C. Stubbs (Harvard)

We report optical observations in the field of the
Fermi/GBM-discovered GRB 230307A (Dalessi et al. GCN Circ. 33407) in
the context of the detection of a possible optical afterglow by Levan
et al. (GCN Circ. 33439).

ATLAS is a quadruple 0.5m telescope system with two units in Hawaii,
one in Chile and one South Africa (see Tonry et al. 2018,
PASP,130:064505), routinely surveying the visible sky on a daily
basis. We promptly process all data with our transient science server
(Smith et al. 2020, PASP, 132:085002). The ATLAS system observed the
field of the GRB 230307A in normal survey mode before the GRB trigger
date of MJD 60010.655 (=2023-03-07 15:44:06.67 UT). We forced the
photometry at the proposed position of the optical afterglow
RA=04:03:25.83, Dec=-75:22:42.7 (J2000) (Levan et al. GCN Circ. 33439;
Source 2 from Evans et al. GCN Circ. 33429) thorough our ATLAS forced
photometry server (Shingles et al. AstroNote #2021-7, Smith et al.
2020, PASP, 132:085002). We found no historical detections of any
excess optical flux at this position.

Forced photometry at those coordinates results in the following most
recent non-detections in the o-band filter. These measurements are not
corrected for any galactic dust extinction. The AB mag are quoted as
2 sigma. 

+-----------+------------+-----------------+-------------------+
|    MJD    | Flux (uJy) | Flux Err (duJy) | AB Mag Limit (2Ïƒ) |
+-----------+------------+-----------------+-------------------+
| 60002.781 |     6.0    |       6.8       |       >21.1       |
+-----------+------------+-----------------+-------------------+
| 60004.034 |    -8.8    |       8.6       |       >20.8       |
+-----------+------------+-----------------+-------------------+
| 60008.087 |     1.1    |       11.9      |       >20.5       |
+-----------+------------+-----------------+-------------------+

The candidate optical afterglow from Levan et al. (GCN Circ. 33439)
was r=20.5 at MJD=60012.1. We find no sign of the object to similar
flux levels before the GRB, which suggests the source is a new
transient occurring after MJD 60008. This supports it being the
candidate optical afterglow of GRB 230307A.


GRB_name: GRB230307A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33444
SUBJECT: GRB 230307A: AGILE/MCAL analysis
DATE:    23/03/09 19:41:32 GMT
FROM:    Claudio Casentini at INAF-IAPS  <claudio.casentini@inaf.it>

C. Casentini (INAF/IAPS), F. Verrecchia (SSDC, and INAF/OAR),
A.Ursi (ASI), C. Pittori (SSDC, and INAF/OAR),
M. Tavani (INAF/IAPS and Uni. Roma Tor Vergata),
F. Lucarelli (SSDC, and INAF/OAR), A. Argan, M. Cardillo, Y. Evangelista,
L. Foffano, G. Piano (INAF/IAPS), A. Addis, L. Baroncelli, A. Bulgarelli,
A. Di Piano, V. Fioretti, G.Panebianco, N. Parmiggiani (INAF/OAS-Bologna),
M. Romani (INAF/OA-Brera), M. Marisaldi (INAF/OAS-Bologna, Bergen
University),
M. Pilia, A. Trois (INAF/OA Cagliari), I. Donnarumma, E. Menegoni,
A. Giuliani (INAF/IASF-Mi) and P. Tempesta (TeleSpazio),
report on behalf of the AGILE Team:

We carried out further analysis of the AGILE/MCAL data of GRB 230307A
(GCNs #33405, #33406, #33407, #33410, #33411, #33412, #33413, #33414,
#33415, #33416, #33418, #33419, #33424, #33425, #33427, #33428, #33429
#33430, #33431, #33434, #33437, #33438, #33439, 33442, 33443)

The burst released 229697 counts in the detector in 18s, above a background
rate of 545 Hz.

The spectral analysis shows a clear component up to 8 MeV.

The time-integrated spectrum of the burst can be fitted in the energy range
0.6-6.5 MeV with a Band model with alpha = -0.43 (+/-0.06),
beta = -5.1 (+/-0.7), peak energy Epeak = 1260 keV (+/- 42 keV).
The fit results in a reduced chi-squared of 1.607 (34 d.o.f.) and a
fluence of 1.3e-03 erg/cm^2, in the same energy range.

MCAL spectrum in the selected 18 s time interval can be found at:
http://www.agilescienceapp.it/notices/GRB230307A_AGILE-MCAL_spectral_analysis.png

Additional analysis of AGILE data is in progress. Automatic MCAL GRB alert
Notices can be found at: https://gcn.gsfc.nasa.gov/agile_mcal.html.


GRB_name: GRB230310A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33445
SUBJECT: GRB 230310A: Fermi GBM Final Real-time Localization
DATE:    23/03/10 00:55:20 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 00:45:01 UT on 10 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230310A (trigger 700101906.130722 / 230310031).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 257.6, Dec = -23.5 (J2000 degrees, equivalent to J2000 17h 10m, -23d 30'), with a statistical uncertainty of 7.2 degrees.

The angle from the Fermi LAT boresight is 120.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230310031/quicklook/glg_skymap_all_bn230310031.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230310031/quicklook/glg_healpix_all_bn230310031.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230310031/quicklook/glg_lc_medres34_bn230310031.gif


GRB_name: GRB230310A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33446
SUBJECT: Fermi GRB 230310A: Global MASTER-Net observations report 
DATE:    23/03/10 01:15:14 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 230310A ( Fermi GBM team, GCN 33445) errorbox  187 sec after notice time and 218 sec after trigger time at 2023-03-10 00:48:39 UT, with upper limit up to  18.0 mag. The observations began at zenith distance = 54 deg. The sun  altitude  is -43.8 deg. 

The galactic latitude b =  9 deg., longitude l =  1 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2203155

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

     249 | 2023-03-10 00:48:39 |         MASTER-SAAO | (17h 11m 56.73s , -17d 55m 16.0s) |   C |    60 | 18.0 |        
     249 | 2023-03-10 00:48:39 |         MASTER-SAAO | (17h 11m 04.28s , -17d 54m 58.3s) |   C |    60 | 17.9 |        
     339 | 2023-03-10 00:50:09 |         MASTER-SAAO | (17h 20m 26.28s , -17d 55m 05.0s) |   C |    60 | 17.4 |        
     339 | 2023-03-10 00:50:09 |         MASTER-SAAO | (17h 19m 33.91s , -17d 54m 48.7s) |   C |    60 | 17.3 |        
     418 | 2023-03-10 00:51:29 |         MASTER-SAAO | (17h 17m 28.93s , -16d 01m 23.8s) |   C |    60 | 18.0 |        
     418 | 2023-03-10 00:51:29 |         MASTER-SAAO | (17h 16m 37.06s , -16d 01m 07.8s) |   C |    60 | 17.7 |        
     510 | 2023-03-10 00:53:01 |         MASTER-SAAO | (17h 25m 51.99s , -15d 59m 37.5s) |   C |    60 | 17.7 |        
     510 | 2023-03-10 00:53:01 |         MASTER-SAAO | (17h 25m 00.18s , -15d 59m 22.0s) |   C |    60 | 17.6 |        
     604 | 2023-03-10 00:54:34 |         MASTER-SAAO | (17h 07m 28.98s , -19d 47m 03.3s) |   C |    60 | 18.0 |        
     604 | 2023-03-10 00:54:34 |         MASTER-SAAO | (17h 06m 35.75s , -19d 46m 48.4s) |   C |    60 | 17.9 |        
     684 | 2023-03-10 00:55:54 |         MASTER-SAAO | (17h 16m 04.51s , -19d 48m 20.0s) |   C |    60 | 17.8 |        
     684 | 2023-03-10 00:55:54 |         MASTER-SAAO | (17h 15m 11.34s , -19d 48m 05.3s) |   C |    60 | 17.6 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB230307A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33447
SUBJECT: GRB 230307A: Gemini-South Confirmation of the Optical Afterglow
DATE:    23/03/10 03:37:36 GMT
FROM:    Brendan O'Connor at UMD  <oconnorb@umd.edu>

B. O'Connor (UMD, GWU), S. Dichiara (PSU), E. Troja (UTV, ASU),
J. Gillanders (UTV), S. B. Cenko (NASA, UMD), C. Kouveliotou (GWU):

We observed GRB 230307A (GBM team GCN 33405, Xiong et al. GCN 33406,
Kozyrev et al. GCN 33425) with the GMOS-S instrument mounted on
Gemini-South in Cerro Pachon, Chile through Director's Time.
Observations began at  00:06:47 UT on 2023-03-10, corresponding to
2.35 d after the GRB trigger.

In a 30 s acquisition image, we detect the optical afterglow reported
by Levan et al. (GCN 33439) and Lipunov et al. (GCN 33441). With
preliminary photometry calibrated to the SkyMapper catalog we derive
a magnitude of r~22.0+/-0.3 mag. This confirms fading of the reported
counterpart and solidifies the connection to the GRB.

Analysis of the spectroscopic observations is underway.

We thank the staff of the Gemini Observatory for rapidly approving and
executing these observations.


GRB_name: GRB230307A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33448
SUBJECT: GRB 230307A: MAXI/GSC upper limit
DATE:    23/03/10 04:03:34 GMT
FROM:    Motoko Serino at Aoyama Gakuin U.  <serino@phys.aoyama.ac.jp>

S. Sugita, M. Serino (AGU), H. Negoro (Nihon U.), T. Mihara (RIKEN),
M. Nakajima, K. Kobayashi, M. Tanaka, Y. Soejima (Nihon U.),
T. Kawamuro, S. Yamada, T. Tamagawa, M. Matsuoka (RIKEN),
T. Sakamoto, H. Hiramatsu, H. Nishikawa, A. Yoshida (AGU),
Y. Tsuboi, J. Kohara, S. Urabe, S. Nawa, N. Nemoto (Chuo U.),
M. Shidatsu, M. Iwasaki (Ehime U.),
N. Kawai, M. Niwano, R. Hosokawa, Y. Imai, N. Ito, Y. Takamatsu (Tokyo Tech),
S. Nakahira, S. Ueno, H. Tomida, M. Ishikawa, T. Kurihara (JAXA),
Y. Ueda, S. Ogawa, K. Setoguchi, T. Yoshitake, K. Inaba, Y. Nakatani (Kyoto U.),
M. Yamauchi, T. Sato, R. Hatsuda, R. Fukuoka, Y. Hagiwara, Y. Umeki (Miyazaki U.),
K. Yamaoka (Nagoya U.),
Y. Kawakubo (LSU),
M. Sugizaki (NAOC) ,
W. Iwakiri (Chiba U.) 
report on behalf of the MAXI team:

We report the non-detection of MAXI/GSC of GRB 230307A 
(Fermi-GBM GCN #33405, #33407 #33411; GECAM GCN #33406, 
Solar Orbiter STIX GCN #33410; AGILE/MCAL GCN #33412;
HEND/Mars Odyssey, INTEGRAL SPI-ACS, Swift/BAT GCN #33413;
AstroSat CZTI GCN #33415; GRBAlpha GCN #33418; 
VZLUSAT-2 GCN #33424; Konus-Wind GCN #33427;
AstroSat LAXPC GCN #33437; ASO-S/HXI GCN #33438;
).
At 15:58:54 UT on 2023-03-07 (888s after the Fermi/GBM trigger),
MAXI/GSC scanned the error region of the event.
The scan time of the five consecutive scans were
17:31:49 (t0+6463s), 19:04:40 (t0+12034s), 20:37:36 (t0+17610s),
22:10:27 (t0+23181s), and 23:43:22 (t0+28756s).
No significant excess emission was detected from the region. 
Typical 1-sigma upper limits in 2-20 keV for one scan (and six scans) are
20 mCrab (and 8 mCrab). 


GRB_name: GRB230307A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33449
SUBJECT: GRB 230307A: GECKO optical observations and detections of the afterglow
DATE:    23/03/10 07:42:47 GMT
FROM:    Myungshin Im at Seoul Nat U  <mim@astro.snu.ac.kr>

Myungshin Im, Gregory S.-H. Paek, Mankeun Jeong, Seo-Won Chang, Hyeonho
Choi (SNU), and Chung-Uk Lee (KASI)

We covered the localization areas of GRB 230307A (GBM team GCN 33405, Xiong
et al. GCN 33406) with the RASA36 telescope at the El Sauce observatory in
Chile, and the KMTNet telescopes in SSO, Australia, and SAAO, South Africa.
The RASA36 observation started at 2023-03-08-00:52 (UT) or about 9.11 hrs
after the burst alert, taking a series of r-band images for about 20 min.
The starting times of the KMTNet SSO and SAAO stations are 2023-03-08-09:39
(UT) and 2023-03-08-18:30 (UT) or 17.89 hrs and 26.74 hrs respectively,
taking a series of R- and I-band images for about 1 hr at each location.

We clearly identify the afterglow (Levan et al. GCN 33439, Lipunov et al.
GCN 33441, O'Conner et al. 33447) and confirm its fading nature in all of
the time-series KMTNet images, with the photometry roughly consistent with
that of the Levan et al. (GCN 33439) report. A weak signal is found in the
RASA36 image.
Further observations and analysis are being carried out.

We thank the KMTNet operators for their support for the KMTNet observations.


GRB_name: GRB230310A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33450
SUBJECT: GRB 230310A: AstroSat CZTI detection
DATE:    23/03/10 21:13:29 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

M. Dixit (IITB), G. Waratkar (IITB), P K. Navaneeth (IUCAA), A. Vibhute 
(IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), 
A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the 
AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 
2021, JApA, 42, 73) showed the detection of a long GRB 230310A which was 
also detected by Fermi GBM (GCN Circ. 33445).

The source was faintly detected in the 20-200 keV energy range. The 
light curve peaks at 2023-03-10 00:44:58.0 UTC. The measured peak count 
rate associated with the burst is 96.2 (+25.5, -26.2) counts/s above the 
background in the combined data of all quadrants, with a total of 562 
(+167, -183) counts. The local mean background count rate was 427.7 
(+1.7, -2.8) counts/s. Using cumulative rates, we measure a T90 of 10.13 
(+3.21, -4.21) s.

It was also faintly detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range. The light curve peaks at 2023-03-10 
00:44:58.0 UTC. The measured peak count rate is 329.8 (+66.1, -68.7) 
counts/s above the background in the combined Veto data of three 
quadrants, with a total of 1912 (+530, -584) counts. The local mean 
background count rate was 2798.0 (+6.4, -7.1) counts/s. We measure a T90 
of 13.94 (+3.25, -5.91) s from the cumulative Veto light curve.

CZTI is built by a TIFR-led consortium of institutes across India, 
including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research 
Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB230308A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33452
SUBJECT: GRB 230308A: CALET Gamma-Ray Burst Monitor detection
DATE:    23/03/11 10:29:09 GMT
FROM:    Yuta Kawakubo at Louisiana State U./CALET  <kawakubo1@lsu.edu>

Y. Shimizu (Kanagawa U), A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U),
T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC),
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The short GRB 230308A (Fermi GBM Final Real-time Localization: 
Fermi GBM team, GCN Circ. 33420; BALROG localization: Kunzweiler et al.,
GCN Circ 33421; AGILE/MCAL detection: Casentini et al., GCN Circ 33435;
Fermi GBM detection: Malacaria et al., GCN Circ 33440) triggered the 
CALET Gamma-ray Burst Monitor (CGBM) at 13:32:27.34 UTC on 8 March 2023
(http://cgbm.calet.jp/cgbm_trigger/flight/1362317395/index.html).
The burst signal was seen by all CGBM detectors.

The burst light curve shows a multi-peaked structure that starts
at T+0.04 sec, peaks at T+0.21 sec, and ends at T+0.37 sec.
The T90 and T50 durations measured by the SGM data are 0.29 +/- 0.04 sec
and 0.17 +/- 0.04 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1362317395/

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.


GRB_name: GRB230307A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33453
SUBJECT: TESS Detection of the Optical Afterglow of GRB230307A
DATE:    23/03/11 16:52:38 GMT
FROM:    Roland Vanderspek at MIT  <roland@space.mit.edu>

R. Vanderspek, M.M. Fausnaugh, R. Jayaraman, G.R. Ricker (MIT), K. Colon and A. Youngblood (GSFC), on behalf of the TESS Team, report:

The Transiting Exoplanet Survey Satellite (TESS; Ricker et al. 2015) observed the location of the bright gamma-ray burst GRB230307A during the second orbit of Observation Sector 62.  Images of the burst region, located in TESS Camera 4, CCD 4, were captured in the TESS full-frame images (FFIs). The observations of the field were made at a cadence of 200 seconds and were continuous from 3 days before the trigger to 3 days after the trigger.

Analysis of the TESS FFIs using TICA (Fausnaugh et al. 2020; doi:10.3847/2515-5172/abd63a <https://ui.adsabs.harvard.edu/link_gateway/2020RNAAS...4..251F/doi:10.3847/2515-5172/abd63a>) data confirms the existence of the optical counterpart reported by Levan et al. (GCN Circular 33439), Lipunov et al. (GCN Circular 33441), O'Conner et al. (GCN Circular 33447), and Im et al. (GCN Circular 33449). The signal is seen as a point source brighter than 15th magnitude in a single 200s FFI.  The measured position is 4:03:26.5, -75:22:45 with an estimated 1-sigma error of 4â€, consistent with previously-reported localizations.   

TICA data can be found at https://archive.stsci.edu/hlsp/tica.


GRB_name: GRB230307A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33459
SUBJECT: GRB 230307A: SOAR/Goodman detection of the possible host galaxy
DATE:    23/03/11 21:13:45 GMT
FROM:    Charles Kilpatrick at Northwestern U  <ckilpatrick@northwestern.edu>

C. R. Bom (CBPF), C. D. Kilpatrick (Northwestern), R. Santucci (Universidade Federal de GoiÃ¡s), A. J. Castro-Tirado (IAA-CSIC and UMA), I. PÃ©rez-GarcÃ­a, Y.-D. Hu (IAA-CSIC), F. Navarete (IAG-USP, RSS/NOIRLab), and M. Makler (UNSAM/CBPF), on behalf of a larger collaboration, report:

Following the detection of the very bright GRB 230307A (Burns et al. GCNC 33414) by Fermi/GBM (the Fermi GBM team, GCNC 33405; Dalessi, GCNC 33407; Dalessi and Roberts, GCNC 33411), GECAM (Xiong et al., GCNC 33406), Solar Orbiter/STIX (Xiao and Krucker, GCNC 33410), AGILE/MCAL (Casentini et al., GCNC. 33412), INTEGRAL/SPI-ACS, Mars-Odyssey/HEND (Kozyrev et al. GCNC 33413), AstroSat/CZTI (Navaneeth et al. GCNC 33415), GRBAlpha (Dafcikova et al. GCNC 33418), VZLUSAT-2 (Ripa et al. GCNC 33424), Konus-WIND (Svinkin et al. GCNC 33427) Swift-BAT (Tohuvavohu, GCNC 33431) and ASO-S/HXI (Li et al. GCNC 33438), we report z-band imaging and optical spectroscopy of the GRB 230307A from 9 and 10 March 2023 with the Goodman high-throughput imaging spectrograph on the SOAR 4.1m telescope at Cerro PachÃ³n, Chile.  The z-band imaging consisted of a cumulative 310s of exposure starting at 2023-03-10T00:13:45 (MJD 60013.0095, 56.5 hr from burst) and 600s starting at 2023-03-11T00:19:08 (MJD 60014.0133, 80.5 hr from burst) at the site of the reported optical counterpart to GRB 230307A (Levan et al. GCNC 33439, Lipunov et al. GCN 33441, Fulton et al. GCNC 33443, O'Connor et al. GCNC 33447, Im et al. GCNC 33449, Vanderspek et al. GCNC 33453).  Using forced photometry at the site of the counterpart (RA=04:03:25.83, Dec=-75:22:42.7), we obtained a marginal detection in both epochs of z=21.8+/-0.3 AB mag. The lack of any change between the two epochs suggests we may be seeing a faint background source consistent with the host galaxy of GRB 230307A.

We also obtained spectroscopy at the site of the counterpart at 2023-03-10T00:28:17 with the 400 l/mm grating on SOAR/Goodman covering a wavelength range of 3000-7000 angstroms for a cumulative exposure time of 1500s.  We oriented the 1.0" Goodman long slit to simultaneously observe the optical afterglow of GRB 230307A and the red source roughly 3 arcseconds to the southwest reported in Levan et al. (GCNC 33439) as a possible host galaxy.  There is no signature of emission from the GRB afterglow in our spectra, but we detect red continuum emission from 6000-7000 angstroms consistent with the r=20.8 mag, i=19.5 mag, z=18.9 mag (Legacy Survey DR10; Dey et al., 2019, AJ, 157, 168) to the southwest.  Combined with the fact that this source is unresolved in our imaging and has a significant parallax in the Gaia DR3 catalog (Gaia Collaboration et al., 2022), we consider this source to be a foreground star as pointed out by Lipunov et al. (GCNC 33441) and not the host galaxy of GRB 230307A.

Based on observations obtained at the Southern Astrophysical Research (SOAR) telescope, which is a joint project of the MinistÃ©rio da CiÃªncia, Tecnologia e InovaÃ§Ãµes do Brasil (MCTI/LNA), the US National Science Foundationâ€™s NOIRLab, the University of North Carolina at Chapel Hill (UNC), and Michigan State University (MSU).


GRB_name: GRB230307A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33461
SUBJECT: Further improved IPN localization for GRB 230307A
DATE:    23/03/11 22:07:23 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin
on behalf of the MGNS/BepiColombo and HEND/Mars Odyssey teams,

J. Benkhoff on behalf of the BepiColombo team,

D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko,
and T. Cline on behalf of the Konus-Wind team,

A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,

E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT team,

and

W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr,
and A.S. Gardner on on behalf of the GRS-Odyssey GRB team,
report:

Using the BepiColombo (MGNS) data we have further improved
the previous IPN box for GRB 230307A (Kozyrev et al., GCN Circ. 33425).
The coordinates of the updated 3 sigma error box are:
---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
    60.867 (04h 03m 28s) -75.382 (-75d 22' 57")
  Corners:
    60.846 (04h 03m 23s) -75.417 (-75d 25' 03")
    61.006 (04h 04m 01s) -75.357 (-75d 21' 26")
    60.889 (04h 03m 33s) -75.348 (-75d 20' 51")
    60.728 (04h 02m 55s) -75.408 (-75d 24' 28")
  ---------------------------------------------
The error box area is 8 sq. arcmin, and its maximum
dimension is 5 arcmin (the minimum one is 1.8 arcmin).
The Sun distance was 80 deg.

This box may be further improved.

The distance between the IPN box center and X-ray/optical
transient position (X-ray Source #2 in Burrows et al., GCN Circ. 33429;
Levan et al., GCN Circ. 33439; Lipunov et al. GCN Circ. 33441;
O'Connor et al., GCN Circ. 33447; Im et al., GCN Circ. 33449;
Vanderspek et al., GCN Circ. 33453)
is 15 arcsec, which further strengthen the interpretation of transient as
the burst afterglow.

An updated triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB230307_T56646/IPN


GRB_name: GRB230309A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33464
SUBJECT: GRB 230309A: AstroSat CZTI detection of a bright long GRB
DATE:    23/03/13 02:59:26 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

G. Waratkar (IITB), M. Dixit (IITB), P K. Navaneeth (IUCAA), A. Vibhute 
(IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), 
A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the 
AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 
2021, JApA, 42, 73) showed the detection of a bright long GRB 230309A.

The source was clearly detected in the 20-200 keV energy range. The 
light curve peaks at 2023-03-09 12:32:21.5 UTC. The measured peak count 
rate associated with the burst is 1281.2 (+67.7 -66.2) counts/s above 
the background in the combined data of all quadrants, with a total of 
7527 (+432 -435) counts. The local mean background count rate was 479.4 
(+2.8 -3.5) counts/s. Using cumulative rates, we measure a T90 of 24.96 
(+2.51 -1.55) s.

It was also clearly detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range. The light curve peaks at 2023-03-09 
12:32:21.5 UTC. The measured peak count rate is 7339.3 (+150.2 -163.3) 
counts/s above the background in the combined Veto data of all 
quadrants, with a total of 36415 (+702 -758) counts. The local mean 
background count rate was 1750.4 (+5.3 -6.0) counts/s. We measure a T90 
of 25.01 (+0.59 -0.59) s from the cumulative Veto light curve.

CZTI is built by a TIFR-led consortium of institutes across India, 
including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research 
Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB230307A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33465
SUBJECT: GRB 230307A: Swift-XRT afterglow detection
DATE:    23/03/13 11:21:46 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

D.N. Burrows (PSU), J. D. Gropp (PSU), J.P. Osborne (U. Leicester),
K.L. Page (U. Leicester), V. D'Elia (SSDC & INAF-OAR), B. Sbarufatti
(INAF-OAB), A. D'Ai (INAF-IASFPA), S. Dichiara (PSU) and P.A. Evans (U.
Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has conducted further observations of the field of the
Fermi/GBM-detected burst GRB 230307A (Dalessi et al. GCN Circ. 33407).
The observations now extend from T0+83.6 ks to T0+437.2 ks. 

Of the sources reported by Burrows et al. (GCN Circ. 33429), "Source 2"
is fading with >3-sigma significance, and is therefore likely the GRB
afterglow. Using 1252 s of PC mode data and 1 UVOT image, we find an
enhanced XRT position (using the XRT-UVOT alignment and matching UVOT
field sources to the USNO-B1 catalogue): RA, Dec = 60.85935, -75.37884
which is equivalent to:

RA (J2000): 04h 03m 26.24s
Dec(J2000): -75d 22' 43.8"

with an uncertainty of 3.2 arcsec (radius, 90% confidence). This
position is 13.3 arcsec from the IPN improved position (Kozyrev et al.
GCN Circ. 33461). 

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.1 (+0.6, -0.5).

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00021537.
The results of the full analysis of the tiled XRT observations are
available at https://www.swift.ac.uk/xrt_products/TILED_GRB00110.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB230307A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33466
SUBJECT: GRB 230307A: soft X-ray detection with LEIA
DATE:    23/03/13 11:24:55 GMT
FROM:    LEIA Team at NAOC/CAS  <ep_ta@bao.ac.cn>

M.J. Liu, Y.L. Wang, Y. Liu, C. Zhang, Z.X. Ling, H.Q. Cheng, C.Z. Cui, D.W. Fan, 
H.B. Hu, J.W. Hu, M.H. Huang, C.C. Jin, D.Y. Li, J.Q. Li, H.Y. Liu, H. Sun, H.W. Pan, 
W.X. Wang, Q.Y. Wu, X.P. Xu, Y.F. Xu, H.N. Yang, M. Zhang, W.D. Zhang, Z. Zhang, 
D.H. Zhao, and W. Yuan (NAOC, CAS), report on behalf of the LEIA and Einstein Probe team:

The prompt emission of the extremely bright long-duration GRB 230307A (Fermi/GBM 
detection: GCN 33405, 33407, 33411, 33414; GECAM-B detection: GCN 33406; 
Solar Orbiter STIX detection: GCN 33410; AGILE/MCAL detection: GCN 33412, 33444; 
IPN triangulation: GCN 33413; AstroSat detection: GCN 33415; BALROG
localization: GCN 33416; GRBAlpha detection: 33418, VZLUSAT-2: GCN 33424,
Konus-Wind GCN 33427, AstroSat CZIT: 33415, Swift/BAT upper limits: GCN 33431, 
AstroSat LAXPC detection: GCN 33437, ASO-S/HXI detection: GCN 33438, MAXI/GSC 
upper limit: GCN 33448) was detected by LEIA (Lobster Eye Imager for Astronomy) 
in the soft X-ray 0.5-4 keV band during one of its monitoring observations of 
the Large Magellanic Cloud. 

The observation was conducted from 2023-03-07T15:43:41 (25 s earlier than the 
Fermi GBM trigger time at 2023-03-07T15:44:06) to 2023-03-07T16:02:00 with 
a net exposure of 761 s. The GRB was detected within the extended FoV 
(about 0.6 deg outside the nominal 18.6deg x 18.6deg FoV) of LEIA, and the 
on-ground calculated position is RA=60.6, Dec=-75.4, with an estimated 3-sigma 
error of 10 arcmin, which is consistent with the IPN localizaition (GCN 33461). 
The lightcurve shows a burst profile which peaked at 2023-03-07T15:44:13 
in 0.5 - 4.0 keV, and droped quickly to a level comparable to the detection 
sensitivity within about 200 s. Given that the source is outside the nominal FoV, 
the estimation of the source flux is complex and subject to further 
investigation and will be published later.  

LEIA also conducted follow-up observations in 6 successive orbits covering 
the entire IPN error box from 2023-03-09UT00:47:26 to 2023-03-09UT10:32:34. 
The total good exposure is around 4000 s and no significant emission was detected. 
The derived upper limit of the LEIA is around 1e-11 erg/cm^2/s 
in the energy band of 0.5 - 4.0 keV.
 
LEIA (Zhang et al, ApJL, 941, 2) is a soft X-ray monitor (0.5 - 4.0 keV)
with a FoV of 340 square degrees aboard the SATech-01 satellite of the CAS,
launched on July 27, 2022. The above result is preliminary and the final
result will be published elsewhere.


GRB_name: GRB230313A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33467
SUBJECT: GRB 230313A: Fermi GBM Final Real-time Localization
DATE:    23/03/13 11:46:22 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 11:38:43 UT on 13 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230313A (trigger 700400328.006796 / 230313485).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 202.4, Dec = 47.2 (J2000 degrees, equivalent to J2000 13h 29m, 47d 12'), with a statistical uncertainty of 1.6 degrees.

The angle from the Fermi LAT boresight is 107.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230313485/quicklook/glg_skymap_all_bn230313485.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230313485/quicklook/glg_healpix_all_bn230313485.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230313485/quicklook/glg_lc_medres34_bn230313485.gif


GRB_name: GRB230313A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33468
SUBJECT: Fermi GRB 230313A: Global MASTER-Net observations report 
DATE:    23/03/13 12:15:14 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-Amur robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Blagoveshchensk State Pedagogical University) started inspect of the Fermi GRB 230313A ( Fermi GBM team, GCN 33467) errorbox  34 sec after notice time and 69 sec after trigger time at 2023-03-13 11:39:52 UT, with upper limit up to  15.6 mag. The observations began at zenith distance = 57 deg. The sun  altitude  is -21.1 deg. 

The galactic latitude b = 69 deg., longitude l = 104 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2204375

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

      74 | 2023-03-13 11:39:52 |         MASTER-Amur | (13h 42m 32.30s , +48d 00m 17.7s) |   C |    10 | 13.3 |        
     114 | 2023-03-13 11:40:27 |         MASTER-Amur | (13h 22m 24.94s , +47d 06m 29.4s) |   C |    20 | 14.3 |        
     159 | 2023-03-13 11:41:06 |         MASTER-Amur | (13h 22m 25.83s , +47d 07m 25.7s) |   C |    30 | 14.6 |        
     213 | 2023-03-13 11:41:56 |         MASTER-Amur | (13h 22m 30.64s , +47d 06m 59.6s) |   C |    40 | 14.6 |        
     278 | 2023-03-13 11:42:55 |         MASTER-Amur | (13h 22m 26.23s , +47d 05m 20.0s) |   C |    50 | 14.9 |        
     352 | 2023-03-13 11:44:05 |         MASTER-Amur | (13h 22m 30.88s , +47d 06m 11.1s) |   C |    60 | 14.8 |        
     457 | 2023-03-13 11:45:40 |         MASTER-Amur | (13h 22m 21.14s , +47d 09m 33.7s) |   C |    80 | 14.9 |        
     567 | 2023-03-13 11:47:19 |         MASTER-Amur | (13h 22m 14.50s , +47d 08m 42.4s) |   C |   100 | 14.9 |        
     701 | 2023-03-13 11:49:19 |         MASTER-Amur | (13h 22m 15.66s , +47d 09m 39.3s) |   C |   130 | 15.0 |        
     866 | 2023-03-13 11:51:48 |         MASTER-Amur | (13h 22m 20.83s , +47d 08m 38.9s) |   C |   160 | 15.5 |        
    1055 | 2023-03-13 11:54:48 |         MASTER-Amur | (13h 22m 15.07s , +47d 07m 36.5s) |   C |   180 | 15.4 |        
    1255 | 2023-03-13 11:58:07 |         MASTER-Amur | (13h 22m 21.36s , +47d 07m 41.7s) |   C |   180 | 15.4 |        
    1454 | 2023-03-13 12:01:27 |         MASTER-Amur | (13h 22m 19.28s , +47d 09m 04.9s) |   C |   180 | 15.5 |        
    1654 | 2023-03-13 12:04:46 |         MASTER-Amur | (13h 22m 19.50s , +47d 07m 47.1s) |   C |   180 | 15.6 |        
    1793 | 2023-03-13 12:08:06 |         MASTER-Amur | (13h 22m 31.48s , +46d 43m 11.8s) |   C |    60 | 14.8 |        
    1873 | 2023-03-13 12:09:26 |         MASTER-Amur | (13h 23m 26.57s , +46d 42m 44.8s) |   C |    60 | 14.8 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB230313A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33469
SUBJECT: GRB 230313A: BALROG localization (Fermi Trigger 700400328 / GRB 230313485)
DATE:    23/03/13 12:42:40 GMT
FROM:    Jochen Greiner at MPE,Garching  <jcg@mpe.mpg.de>

B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
700400328 at 11:38:43 on 13 March 2023 were automatically fitted for spectrum
and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427;
Berlato et al. 2019, ApJ 873, 60).

The best-fit position (1 sigma statistical errors) is:
RA(2000.0) = 201.0+/-2.1 deg
Decl.(2000.0) = 52.3+/-2.3 deg
We estimate an additional systematic error of 2 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB230313485/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB230313485/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB230313485/json

                        


GRB_name: GRB230307A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33471
SUBJECT: GRB 230307A: Swift/UVOT detection
DATE:    23/03/13 15:54:52 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>

A. A. Breeveld (UCL-MSSL), and C. Salvaggio (INAF-OAB) report on behalf 
of the Swift/UVOT team:

The Swift/UVOT began observations of the field of GRB 230307A 99.5 ks 
after the Fermi/GBM-detected trigger (Dalessi et al., GCN 33407).
A fading source consistent with the enhanced XRT position (Burrows et 
al., GCN 33465) and consistent with the optical counterpart reported by 
Levan et al. (GCN 33439), Lipunov et al. (GCN 33441), Fulton et al. (GCN 
33443), O'Connor et al. (GCN 33447), Im et al. (GCN 33449), Vanderspek 
et al. (GCN 33453) and Bom et al. (GCN 33459) is detected in the initial 
UVOT exposures. Detections and 3 sigma upper limits are given in the 
following table:

Filter      T_start(s) T_stop(s)   Exp(s)   Mag

white        99525      110441      2265     21.28 +/- 0.16
white       133031      208070      2931     22.09 +/- 0.32
white       212899      420530      3418    >22.25
u            83621       88252       422    >20.44

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 0.084 in the direction of 
the burst (Schlegel et al. 1998).


GRB_name: GRB230307A
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33472
SUBJECT: GRB 230307A: INTEGRAL upper limit on Hard X-ray afterglow
DATE:    23/03/13 16:54:30 GMT
FROM:    Volodymyr Savchenko at ISDC,U of Geneve  <savchenk@in2p3.fr>

At the time of the very bright GRB 230307A (GCN #33405, GCN #33406, GCN 
#33407, GCN #33410, GCN #33411, GCN #33412, GCN #33413, GCN #33414, GCN 
#33415, GCN #33416, GCN #33418, GCN #33419, GCN #33424, GCN #33425, GCN 
#33427, GCN #33428, GCN #33429, GCN #33430, GCN #33431, GCN #33434, GCN 
#33437, GCN #33438, GCN #33439, GCN #33442, GCN #33443, GCN #33444, GCN 
#33447, GCN #33448, GCN #33449, GCN #33453, GCN #33459, GCN #33461, GCN 
#33465, GCN #33466), INTEGRAL was pointing 74 deg from the GRB 
direction. Such an exceptionally high flux lead to a detection in 
various ratemeters of INTEGRAL often causing saturation. From moderately 
saturated SPI-ACS observation, we can estimate a likely close lower 
limit on the total flux in 75 - 2000 keV energy range at the level of 
0.0015 erg cm-2 s-1 in the time range T0 to T0+130.0s where T0 = 
2023-03-07T15:44:07.

We note that despite the GRB brightness, both SPI-ACS and PICsIT 
observations do not reveal early afterglow and no emission past 
T0+129~s, with an approximate upper limit on average 75-2000 keV flux 
between T0+129s and of T0+259 s at the level of 5.8e-09 erg cm-2 s-1 
(see also GCN#33431).

A ToO pointed observation was carried out from 2023-03-08 11:35:00 (T0 + 
19.8 hours) to 2023-03-09 02:18:20 (T0 + 34.6 hours) with a total 
exposure time of 28.2 ks (for ISGRI). Since the observation was 
scheduled when the refined IPN localization was not yet available, the 
position of the candidate GRB optical and X-ray afterglow ((GCN #33429, 
GCN #33439, GCN #33443, GCN #33447, GCN #33449, GCN #33459, GCN #33465)) 
was observed at an offset of 1.3 deg, reducing somewhat the effective 
exposure of JEM-X compared to an optimal pointing.

We do not find any significant signal, and put a limit on any source 
within the IPN error box, including also to the possible X-ray and 
optical afterglow, at the level of 4.2e-11 erg cm-2 s-1 in the 3-200 keV 
energy range, assuming a powerlaw spectrum with a slope of -2. This 
limit is about 1.2 orders of magnitude lower than the detection in the 
case of GRB 221009A.

We are grateful to the INTEGRAL Ground Segment team for the quick 
scheduling of these observations.

All of the results except PICsIT were produced MMODA platform 
(https://www.astro.unige.ch/mmoda/).


GRB_name: GRB230314A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33474
SUBJECT: GRB 230314A: Fermi GBM Final Real-time Localization
DATE:    23/03/14 03:01:40 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 02:51:24 UT on 14 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230314A (trigger 700455089.129136 / 230314119).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 236.4, Dec = 74.8 (J2000 degrees, equivalent to J2000 15h 45m, 74d 47'), with a statistical uncertainty of 4.6 degrees.

The angle from the Fermi LAT boresight is 40.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230314119/quicklook/glg_skymap_all_bn230314119.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230314119/quicklook/glg_healpix_all_bn230314119.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230314119/quicklook/glg_lc_medres34_bn230314119.gif


GRB_name: GRB230307A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33475
SUBJECT: GRB 230307A: ATCA radio detection
DATE:    23/03/14 05:23:06 GMT
FROM:    Gemma Anderson at Curtin U  <gemma.anderson@curtin.edu.au>

G. E. Anderson (Curtin Uni.), J. K. Leung (U. Sydney), T. Murphy (U. Sydney), E. Lenc (CSIRO)
L. Rhodes (U. Oxford), A. J. van der Horst (GWU), G. Rowell (U. Adelaide)

We observed GRB 230703A (Fermi GBM Team GCN 33405) with the Australia Telescope
Compact Array (ATCA) between 2023-03-12_02:30 UT and 2023-03-12_07:30 UT
(~4.5 days post-burst). In our preliminary analysis, we detect a radio source coincident
with the X-ray (Burrows et al. GCN 33429, GCN 33465) and optical (Levan et al. GCN 33439)
counterpart with a flux density of 120+/-30 microJy/beam at 9 GHz. We also obtain an
3 sigma upper limit of 90 microJy/beam at 5.5 GHz.

We thank CSIRO staff for supporting these observations.

The ATCA is part of the Australia Telescope National Facility which is funded by the Australian
Government for operation as a National Facility managed by CSIRO. We acknowledge the Gomeroi
people as the traditional owners of the Observatory site.


GRB_name: GRB230314A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33476
SUBJECT: Fermi GRB 230314A: Global MASTER-Net observations report 
DATE:    23/03/14 10:45:22 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-Amur robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Blagoveshchensk State Pedagogical University) started inspect of the Fermi GRB 230314A ( Fermi GBM team, GCN 33474) errorbox  27256 sec after notice time and 27291 sec after trigger time at 2023-03-14 10:26:15 UT, with upper limit up to  13.9 mag. Observations started at twilight.  The observations began at zenith distance = 53 deg. The sun  altitude  is -9.5 deg. 

The galactic latitude b = 38 deg., longitude l = 110 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2204543

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   27322 | 2023-03-14 10:26:15 |         MASTER-Amur | (16h 07m 24.95s , +75d 14m 49.7s) |   C |    60 | 12.5 |        
   27401 | 2023-03-14 10:27:35 |         MASTER-Amur | (15h 37m 46.79s , +73d 22m 21.4s) |   C |    60 | 12.9 |        
   27482 | 2023-03-14 10:28:55 |         MASTER-Amur | (16h 05m 41.11s , +73d 21m 07.8s) |   C |    60 | 12.6 |        
   27569 | 2023-03-14 10:30:22 |         MASTER-Amur | (15h 34m 45.47s , +77d 09m 41.4s) |   C |    60 | 13.3 |        
   27648 | 2023-03-14 10:31:42 |         MASTER-Amur | (16h 10m 58.71s , +77d 11m 33.8s) |   C |    60 | 13.4 |        
   27728 | 2023-03-14 10:33:02 |         MASTER-Amur | (14h 36m 06.57s , +75d 13m 56.6s) |   C |    60 | 13.8 |        
   27807 | 2023-03-14 10:34:21 |         MASTER-Amur | (15h 07m 35.35s , +75d 14m 30.1s) |   C |    60 | 13.9 |        
   27887 | 2023-03-14 10:35:41 |         MASTER-Amur | (15h 40m 02.27s , +71d 27m 17.7s) |   C |    60 | 13.7 |        
   27967 | 2023-03-14 10:37:01 |         MASTER-Amur | (16h 05m 15.35s , +71d 29m 04.3s) |   C |    60 | 13.6 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB230308A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33477
SUBJECT: IPN triangulation of GRB 230308A (short/bright)
DATE:    23/03/14 19:42:15 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin
on behalf of the MGNS/BepiColombo and HEND/Mars Odyssey teams,

J. Benkhoff on behalf of the BepiColombo team,

D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko,
and T. Cline on behalf of the Konus-Wind team,

A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,

E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

and

W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr,
and A.S. Gardner on on behalf of the GRS-Odyssey GRB team,
report:

The bright, short-duration GRB 230308A
(Fermi-GBM detection: the Fermi GBM team, GCN Circ. 33420;
Malacaria et al., GCN Circ. 33440;
BALROG localization: Kunzweiler et al., GCN Circ. 33421;
AGILE-MCAL detection: Casentini et al., GCN Circ. 33435)
was detected by Fermi(GBM trigger 699975152), Konus-Wind,
INTEGRAL (SPI-ACS), AGILE (MCAL), Mars-Odyssey (HEND),
and BepiColombo (MGNS) at about 48747 s UT (13:32:27).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
    96.381 (06h 25m 31s) +66.621 (+66d 37' 17")
  Corners:
    96.568 (06h 26m 16s) +66.648 (+66d 38' 51")
    96.345 (06h 25m 23s) +66.681 (+66d 40' 53")
    96.194 (06h 24m 47s) +66.595 (+66d 35' 42")
    96.417 (06h 25m 40s) +66.562 (+66d 33' 42")
  ---------------------------------------------
The error box area is 35 sq. arcmin, and its maximum
dimension is 9 arcmin (the minimum one is 6.1 arcmin).
The Sun distance was 101 deg.

This box may be improved.

The IPN localization is consistent with, but reduces the area of,
the Fermi-GBM final localization (GCN 33420) and the BALROG localization 
(GCN 33421).

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB230308_T48747/IPN/

The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.


GRB_name: GRB230307A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33478
SUBJECT: GRB 230307A: Far off-axis NuSTAR detection of the GRB
DATE:    23/03/14 21:10:47 GMT
FROM:    Brian Grefenstette at Caltech/NuSTAR  <bwgref@srl.caltech.edu>

B.W. Grefenstette (Caltech) on behalf of the NuSTAR Team

After notification of the GRB 230307A via numerous GCNs, we searched the NuSTAR event stream for signals near the time of the GRB. Using a nominal position of RA:60.819 Dec:-75.379 (GCN #33425) we estimate the GRB was ~140-deg away from the telescope boresight (e.g., coming through the side of the instrument).

Even so, we clearly see the GRB in the CsI anti-coincidence shields in both of the NuSTAR telescopes. In the 1-sec time resolution shield data we see bursts in excess of 25,000 cps above the LLD in the shield at 2023-03-07T15:44:07.5 and a brighter second peak at 2023-03-07T15:44:11.5, along with a dip at 2023-03-07T15:44:23.5 as also seen in the GRBAlpha (GCN 33418) lightcurves. The energy scale for the LLD on the CsI is not well calibrated for incident gamma-rays, but this can roughly be interpreted as counts above ~100 keV.

The GRB is also seen in the CdZnTe X-ray detectors of both telescopes. The high rate of shield hits and the temporal variations in the intrinsic flux makes interpreting the CdZnTe lightcurve difficult. NuSTAR detected roughly 1000 events per telescope during the burst, with measured rates on the order of 5  50 counts per second throughout the burst and energies ranging from a few keV up to the saturation level of the detectors around 250 keV.

We clearly see that the GRB is resolved into several peaks, with significant relative spectral evolution between the first and second peaks with the second peak seen to have slightly lower energies in the X-rays, though whether this is instrument or intrinsic remains to be seen.


GRB_name: GRB230313A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33479
SUBJECT: GRB 230313A: AstroSat CZTI detection
DATE:    23/03/15 03:17:07 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

A. Ahmad (IITB), G. Waratkar (IITB), P K. Navaneeth (IUCAA), A. Vibhute 
(IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), 
A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the 
AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 
2021, JApA, 42, 73) showed the detection of a long GRB 230313A which was 
also detected by Fermi GBM (GCN Circ. 33467).

The source was faintly detected in the 20-200 keV energy range. The 
light curve peaks at 2023-03-13 11:38:43.9 UTC. The measured peak count 
rate associated with the burst is 211.1 (+167.6 -9.9) counts/s above the 
background in the combined data of three quadrants (out of four), with a 
total of 259 (+104 -110) counts. The local mean background count rate 
was 371.0 (+8.7 -8.6) counts/s. Using cumulative rates, we measure a T90 
of 3.68 (+0.61 -2.44) s.

It was also faintly detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range. The light curve peaks at 2023-03-13 
11:38:43.2 UTC. The measured peak count rate is 270.4 (+59.6 -65.5) 
counts/s above the background in the combined Veto data of three 
quadrants (out of four), with a total of 463 (+172 -181) counts. The 
local mean background count rate was 1116.0 (+5.4 -6.4) counts/s. We 
measure a T90 of 4.28 (+1.18 -3.20) s from the cumulative Veto light 
curve.

CZTI is built by a TIFR-led consortium of institutes across India, 
including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research 
Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB230304B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33480
SUBJECT: IPN triangulation of GRB 230304B
DATE:    23/03/15 14:52:07 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin
on behalf of the MGNS/BepiColombo and HEND/Mars Odyssey teams,

J. Benkhoff on behalf of the BepiColombo team,

D. Svinkin, D. Frederiks, A. Ridnaia, A. Lysenko,
and T. Cline on behalf of the Konus-Wind team,

A. Goldstein, M. S. Briggs, C. Wilson-Hodge,
and E. Burns on behalf of the Fermi GBM team,

E. Bozzo and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

and

W. Boynton, C. Fellows, K. Harshman, H. Enos, R. Starr,
and A.S. Gardner on on behalf of the GRS-Odyssey GRB team,
report:

The long-duration GRB 230304B
(Fermi-GBM detection: the Fermi GBM team, GCN Circ. 33396;
GRBAlpha detection: Dafcikova et al., GCN Circ. 33398;
AstroSat-CZTI detection: Navaneeth et al., GCN Circ. 33400;
CALET-GBM detection: Kobayashi et al., GCN Circ. 33423)
was detected by Fermi (GBM trigger 699633354),
Konus-Wind, INTEGRAL (SPI-ACS), GRBAlpha, AstroSat (CZTI),
CALET (GBM), BepiColombo (MGNS), and Mars-Odyssey (HEND),
at about 52549 s UT (14:35:49).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   110.440 (07h 21m 46s)  -2.113 ( -2d 06' 48")
  Corners:
   110.528 (07h 22m 07s)  -2.101 ( -2d 06' 03")
   110.345 (07h 21m 23s)  -2.288 ( -2d 17' 16")
   110.352 (07h 21m 24s)  -2.126 ( -2d 07' 33")
   110.535 (07h 22m 08s)  -1.938 ( -1d 56' 16")
  ---------------------------------------------
The error box area is 103 sq. arcmin, and its maximum
dimension is 24 arcmin (the minimum one is 6.5 arcmin).
The Sun distance was 124 deg.

This box may be improved.

The IPN localization is consistent with, but reduces the area of,
the Fermi-GBM final localization (GCN 33396).

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB230304_T52553/IPN/

The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.


GRB_name: GRB230316A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33481
SUBJECT: GRB 230316A: Fermi GBM Final Real-time Localization
DATE:    23/03/16 13:16:50 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 13:06:30 UT on 16 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230316A (trigger 700664795.31625 / 230316546).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 273.1, Dec = -64.9 (J2000 degrees, equivalent to J2000 18h 12m, -64d 54'), with a statistical uncertainty of 1.7 degrees.

The angle from the Fermi LAT boresight is 54.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230316546/quicklook/glg_skymap_all_bn230316546.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230316546/quicklook/glg_healpix_all_bn230316546.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230316546/quicklook/glg_lc_medres34_bn230316546.gif


GRB_name: GRB230304D
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33482
SUBJECT: GRB 230304D: AstroSat CZTI detection
DATE:    23/03/16 15:53:08 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

P K. Navaneeth (IUCAA), R. Gopalakrishnan (IUCAA), G. Waratkar (IITB), 
A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka 
University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report 
on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 
2021, JApA, 42, 73) showed the detection of a long GRB 230304D which was 
also detected by Fermi - GBM (Trigger Number - 699634754).

The source was clearly detected in the 20-200 keV energy range. The 
light curve showed multiple peaks of emission with the strongest peak at 
2023-03-04 14:59:21.50 UTC. The measured peak count rate associated with 
the burst is 313 (+45, -41) counts/s above the background in the 
combined data of all quadrants, with a total of 2489 (+402, -322) 
counts. The local mean background count rate was 443 (+2, -4) counts/s. 
Using cumulative rates, we measure a T90 of 25.52 (+5, -2) s.

The source was also clearly detected in the CsI anticoincidence (Veto) 
detector in the 100-500 keV energy range. The light curve showed 
multiple peaks of emission with the strongest peak at 2023-03-04 
14:59:20.91 UTC. The measured peak count rate associated with the burst 
is 390 (+67, -68) counts/s above the background in the combined data of 
all quadrants, with a total of 2433 (+610, -813) counts. The local mean 
background count rate was 1355 (+5, -5) counts/s. We measure a T90 of 
25.84 (+11, -17) s from the cumulative Veto light curve.

CZTI is built by a TIFR-led consortium of institutes across India, 
including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research 
Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB230316A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33483
SUBJECT: Fermi GRB 230316A: Global MASTER-Net observations report 
DATE:    23/03/16 22:15:40 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 230316A ( Fermi GBM team, GCN 33481) errorbox  29242 sec after notice time and 29277 sec after trigger time at 2023-03-16 21:14:27 UT, with upper limit up to  18.3 mag. The observations began at zenith distance = 71 deg. The sun  altitude  is -49.7 deg. 

The galactic latitude b = -21 deg., longitude l = 330 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2204841

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   29307 | 2023-03-16 21:14:27 |         MASTER-SAAO | (17h 59m 53.97s , -65d 22m 36.4s) |   C |    60 | 18.2 |        
   29307 | 2023-03-16 21:14:27 |         MASTER-SAAO | (17h 58m 01.94s , -65d 22m 50.5s) |   C |    60 | 18.2 |        
   29399 | 2023-03-16 21:15:59 |         MASTER-SAAO | (18h 19m 10.39s , -65d 22m 26.0s) |   C |    60 | 18.1 |        
   29399 | 2023-03-16 21:15:59 |         MASTER-SAAO | (18h 17m 18.78s , -65d 22m 37.3s) |   C |    60 | 18.2 |        
   29479 | 2023-03-16 21:17:18 |         MASTER-SAAO | (17h 55m 39.92s , -63d 28m 28.8s) |   C |    60 | 18.1 |        
   29479 | 2023-03-16 21:17:18 |         MASTER-SAAO | (17h 53m 55.47s , -63d 28m 39.4s) |   C |    60 | 18.3 |        
   29558 | 2023-03-16 21:18:38 |         MASTER-SAAO | (18h 13m 37.19s , -63d 26m 55.0s) |   C |    60 | 18.0 |        
   29558 | 2023-03-16 21:18:38 |         MASTER-SAAO | (18h 11m 53.06s , -63d 27m 05.8s) |   C |    60 | 18.2 |        
   29649 | 2023-03-16 21:20:09 |         MASTER-SAAO | (18h 06m 10.38s , -67d 14m 35.3s) |   C |    60 | 18.3 |        
   29649 | 2023-03-16 21:20:09 |         MASTER-SAAO | (18h 04m 09.36s , -67d 14m 45.8s) |   C |    60 | 18.3 |        
   29729 | 2023-03-16 21:21:29 |         MASTER-SAAO | (18h 26m 57.03s , -67d 15m 48.7s) |   C |    60 | 18.2 |        
   29729 | 2023-03-16 21:21:29 |         MASTER-SAAO | (18h 24m 56.18s , -67d 15m 59.6s) |   C |    60 | 18.3 |        
   29821 | 2023-03-16 21:23:00 |         MASTER-SAAO | (18h 27m 58.63s , -63d 28m 57.2s) |   C |    60 | 18.1 |        
   29821 | 2023-03-16 21:23:01 |         MASTER-SAAO | (18h 29m 42.75s , -63d 28m 46.6s) |   C |    60 | 17.9 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB230309A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33484
SUBJECT: IPN triangulation of GRB 230309A
DATE:    23/03/17 14:32:30 GMT
FROM:    Anna Ridnaia at Ioffe Institute  <ridnaia@mail.ioffe.ru>

A.S. Kozyrev, D.V. Golovin, M.L. Litvak, I.G. Mitrofanov, and A.B. Sanin
on behalf of the MGNS/BepiColombo team,

J. Benkhoff on behalf of the BepiColombo team,

A. Ridnaia, D. Frederiks, D. Svinkin, A. Lysenko,
and T. Cline on behalf of the Konus-Wind team,

and

S. Barthelmy, J. Cummings, H. Krimm, D. Palmer, and A. Tohuvavohu
on behalf of the Swift-BAT team, report:

The bright, long-duration GRB 230309A
(AstroSat CZTI detection: Waratkar et al., GCN Circ. 33464)
was detected by Konus-Wind, Swift (BAT), AstroSat (CZTI),
and BepiColombo (MGNS), at about 45138 s UT (12:32:18).
The burst was outside the coded field of view of the BAT.

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
 ---------------------------------------------
  RA(2000), deg                 Dec(2000), deg
 ---------------------------------------------
 Center:
   88.882 (05h 55m 32s) -62.196 (-62d 11' 45")
 Corners:
   88.454 (05h 53m 49s) -63.663 (-63d 39' 48")
   88.326 (05h 53m 18s) -63.585 (-63d 35' 05")
   89.273 (05h 57m 06s) -60.728 (-60d 43' 40")
   89.391 (05h 57m 34s) -60.806 (-60d 48' 20")
 ---------------------------------------------
The error box area is 712 sq. arcmin, and its maximum
dimension is 2.9 deg (the minimum one is 4 arcmin).
The Sun distance was about 90 deg.

This localization may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB230309_T45138/IPN/

The Konus-Wind time history and spectrum will be given in a forthcoming
GCN Circular.


GRB_name: GRB230307A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33485
SUBJECT: GRB 230307A: Continued Gemini-South observations confirm rapid optical fading 
DATE:    23/03/17 16:06:24 GMT
FROM:    James Gillanders at University of Rome Tor Vergata  <jhgillanders.astro@gmail.com>

J. Gillanders (UTV), B. O'Connor (UMD, GWU), S. Dichiara (PSU), and E. 
Troja (UTV, ASU) report on behalf of a larger team:

We re-observed the field of GRB 230307A (GBM team GCN 33405, Xiong et al.
GCN 33406) with the GMOS-S spectrograph at Gemini-South through Director's
Discretionary Time (PI: Oâ€™Connor). 

Our initial epoch was carried out at 2.4 d post-burst. We performed 4x1000 s
exposures with the R400 grating covering wavelengths 4100-9200 angstroms.
The brightness in the initial acquisition image (r~22 AB mag) was reported
in O'Connor et al. (GCN 33447). A weak trace is visible from this position
down to ~5300 angstroms, which sets an upper limit of z<4.3 to the GRB
redshift. No obvious emission or absorption features are visible in the
spectrum.

Our slit also covered a nearby bright galaxy at an offset of ~30â€. We estimate
a redshift z~0.065 from Halpha, N II, and S II emission lines. If this galaxy
(RA=+60.8280, DEC=-75.3819) is the host, then the GRB would have a projected
offset of ~40 kpc. The probability of chance coincidence is ~0.08.

Our latest observations were carried out in z-band at approximately 8.4 d
post-burst. A faint source is significantly detected at the location of the
optical counterpart (Levan et al. GCN 33439,  O'Connor et al. GCN 33447), and
indicates a rapid fading of the afterglow by approximately 2 mag with respect
to earlier measurements. This suggests that the source reported by Bom et al.
(GCN 33459) is not the GRB host galaxy. Additionally, the observed power-law
temporal slope of ~-2 appears consistent with a jet-break.

We thank Andrew Levan for providing an initial finding chart and the staff of
the Gemini Observatory for rapidly approving and executing these observations. 


GRB_name: GRB230314A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33488
SUBJECT: GRB 230314A: TURBO Optical Upper Limit
DATE:    23/03/20 20:52:00 GMT
FROM:    Robert Strausbaugh at University of Minnesota  <rstrausb@umn.edu>

R. Strausbaugh (UMN), D. Warshofsky (UMN), P. L. Kelly (UMN), M. Tran (UMN)
report on behalf of a larger collaboration:

We observed the GRB 2303014A (Fermi GBM Team, GCN 33474) field with the
Total-Coverage Ultrafast Response to Binary-Mergers Observatory (TURBO)
prototype telescope in St. Paul, Minnesota on March 14, from 05:02 to 08:36
UT (corresponding to 2.01 to 5.52 hours after GRB trigger) in SDSS g and
r-band filters.

We acquired a series of 30x60s exposures over the entire observing period
in each band covering an area of about 12 square degrees with corners for
each field listed in the table below.  We do not detect any fading sources
in the GBM error region in either band, consistent with available optical
upper limits (Lipunov et al., GCN 33249).

The following 3-sigma upper limits in AB magnitudes are calculated using
the Pan-STARRS catalog as reference:

Filt. | Corners of fields (hh:mm:ss,dd:mm:ss)| Upper Limit

â€”---------------------------------------------------------------------------------------------

g | (15:08:41,+75:20:31) ,(16:08:31,+74:24:12) |18.2

â€”---------------------------------------------------------------------------------------------

r | (16:06:24,+75:12:04) ,(15:08:34,+74:04:37) |18.6

â€”---------------------------------------------------------------------------------------------

g | (15:20:58,+75:20:08) ,(16:20:45,+74:23:31) |18

â€”---------------------------------------------------------------------------------------------

r | (16:18:28,+75:12:01) ,(15:20:35,+74:03:47) |18.7

â€”---------------------------------------------------------------------------------------------

g | (15:12:17,+73:21:35) ,(16:05:17,+72:25:04) |18.3

â€”---------------------------------------------------------------------------------------------

r |(16:03:27 ,+73:12:08) ,(15:12:06,+72:04:05) |18.7

â€”---------------------------------------------------------------------------------------------

g | (15:24:16,+73:21:38) ,(16:17:16,+72:25:03) |18.1

â€”---------------------------------------------------------------------------------------------

r | (16:15:22,+73:12:30) ,(15:23:58,+72:04:42) |18.7

â€”---------------------------------------------------------------------------------------------

g | (15:04:23,+77:18:32) ,(16:13:02,+76:22:15) |18.2

â€”---------------------------------------------------------------------------------------------

r | (16:10:49,+77:10:25) ,(15:04:38,+76:01:38) |18.6

â€”---------------------------------------------------------------------------------------------

g | (15:16:20,+77:18:47) ,(16:24:59,+76:22:30) |18.1

â€”---------------------------------------------------------------------------------------------

r | (16:22:46,+77:10:29) ,(15:16:35,+76:01:37) |18.7

These magnitudes are not corrected for foreground Galactic extinction.

The TURBO prototype in St. Paul consists of two co-mounted 11-inch
telescopes each with a 6.6 square degree field of view. TURBO will consist
of two arrays of 8 pairs of co-mounted 11-inch telescopes at two dark-sky
sites: Magdalena Ridge Observatory, New Mexico, USA and Skinakas
Observatory, Crete, Greece.


GRB_name: GRB230320A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33489
SUBJECT: GRB 230320A: Fermi GBM Final Real-time Localization
DATE:    23/03/20 22:56:34 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely SHORT GRB

At 22:46:06 UT on 20 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230320A (trigger 701045171.191836 / 230320949).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 253.7, Dec = -37.0 (J2000 degrees, equivalent to J2000 16h 54m, -37d 00'), with a statistical uncertainty of 15.0 degrees.

The angle from the Fermi LAT boresight is 36.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230320949/quicklook/glg_skymap_all_bn230320949.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230320949/quicklook/glg_healpix_all_bn230320949.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230320949/quicklook/glg_lc_medres34_bn230320949.gif


GRB_name: GRB230321A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33490
SUBJECT: GRB 230321A: Fermi GBM Final Real-time Localization
DATE:    23/03/21 04:32:02 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 04:21:43 UT on 21 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230321A (trigger 701065308.721614 / 230321182).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 74.8, Dec = 28.0 (J2000 degrees, equivalent to J2000 04h 59m, 28d 00'), with a statistical uncertainty of 6.2 degrees.

The angle from the Fermi LAT boresight is 53.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230321182/quicklook/glg_skymap_all_bn230321182.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230321182/quicklook/glg_healpix_all_bn230321182.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230321182/quicklook/glg_lc_medres34_bn230321182.gif


GRB_name: GRB230321A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33491
SUBJECT: GRB 230321A: BALROG localization (Fermi Trigger 701065308 / GRB 230321182)
DATE:    23/03/21 04:42:41 GMT
FROM:    Jochen Greiner at MPE,Garching  <jcg@mpe.mpg.de>

F. Kunzweiler, B. Biltzinger, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:

The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
701065308 at 04:21:43 on 21 Mar. 2023 were automatically fitted for spectrum
and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427;
Berlato et al. 2019, ApJ 873, 60).

The best-fit position (1 sigma statistical errors) is:
RA(2000.0) = 65.24+/-1.54 deg
Decl.(2000.0) = 31.70+/-1.26 deg
We estimate an additional systematic error of 2 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB230321182/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB230321182/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB230321182/json    


GRB_name: GRB230320B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33492
SUBJECT: GRB 230320B: AstroSat CZTI detection
DATE:    23/03/21 09:11:08 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

P K. Navaneeth (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. 
Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao 
(IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat 
CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 
2021, JApA, 42, 73) showed the detection of a long GRB 230320B which was 
also detected by Fermi GBM (TrigNum: 701039550), CALET (ID Num: 
1363381768) and GECAM (TrigNum: 163).

The source was clearly detected in the 20-200 keV energy range. The 
light curve peaks at 2023-03-20 21:12:27.50 UTC. The measured peak count 
rate associated with the burst is 415 (+48, -33) counts/s above the 
background in the combined data of three quadrants (out of four), with a 
total of 1976 (+332, -251) counts. The local mean background count rate 
was 360 (+2, -3) counts/s. Using cumulative rates, we measure a T90 of 
11.27 (+6, -4) s.

The source was also clearly detected in the CsI anticoincidence (Veto) 
detector in the 100-500 keV energy range. The light curve peaks at 
2023-03-20 21:12:26.59 UTC. The measured peak count rate associated with 
the burst is 377 (+80, -44) counts/s above the background in the 
combined data of all quadrants, with a total of 1527 (+371, -423) 
counts. The local mean background count rate was 1564 (+4, -4) counts/s. 
We measure a T90 of 12.92 (+8, -4) s from the cumulative Veto light 
curve.

CZTI is built by a TIFR-led consortium of institutes across India, 
including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research 
Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb [1]

Links:
------
[1] http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB230321B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33493
SUBJECT: GRB 230321B: AstroSat CZTI detection
DATE:    23/03/21 09:15:13 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

P K. Navaneeth (IUCAA), G. Waratkar (IITB), R. Gopalakrishnan (IUCAA), 
A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka 
University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report 
on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 
2021, JApA, 42, 73) showed the detection of a long GRB 230321B which was 
also detected by Fermi GBM (TrigNum: 701058254) and KONUS-Wind.

The source was clearly detected in the 20-200 keV energy range. The 
light curve peaks at 2023-03-21 02:24:13.35 UTC. The measured peak count 
rate associated with the burst is 426 (+186, -1) counts/s above the 
background in the combined data of three quadrants (out of four), with a 
total of 1195 (+203, -204) counts. The local mean background count rate 
was 361 (+6, -8) counts/s. Using cumulative rates, we measure a T90 of 
5.57 (+2, -1) s.

The source was also clearly detected in the CsI anticoincidence (Veto) 
detector in the 100-500 keV energy range. The light curve peaks at 
2023-03-21 02:24:10.58 UTC. The measured peak count rate associated with 
the burst is 268 (+80, -39) counts/s above the background in the 
combined data of all quadrants, with a total of 1050 (+324, -377) 
counts. The local mean background count rate was 1568 (+6, -6) counts/s. 
We measure a T90 of 5.24 (+3, -2) s from the cumulative Veto light 
curve.

CZTI is built by a TIFR-led consortium of institutes across India, 
including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research 
Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB230321A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33497
SUBJECT: Fermi GRB 230321A: Global MASTER-Net observations report 
DATE:    23/03/21 14:15:09 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-Amur robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Blagoveshchensk State Pedagogical University) started inspect of the Fermi GRB 230321A ( Fermi GBM team, GCN 33490) errorbox  31100 sec after notice time and 31106 sec after trigger time at 2023-03-21 13:00:10 UT, with upper limit up to  17.0 mag. The observations began at zenith distance = 54 deg. The sun  altitude  is -29.6 deg. 

The galactic latitude b = -8 deg., longitude l = 175 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2205320

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   31137 | 2023-03-21 13:00:10 |         MASTER-Amur | (05h 01m 25.52s , +27d 54m 19.8s) |   C |    60 | 17.0 |        
   31219 | 2023-03-21 13:01:32 |         MASTER-Amur | (05h 10m 28.51s , +27d 52m 42.3s) |   C |    60 | 16.9 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB230320A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33498
SUBJECT: Fermi GRB 230320A: Global MASTER-Net observations report 
DATE:    23/03/21 20:15:20 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 230320A ( Fermi GBM team, GCN 33489) errorbox  76358 sec after notice time and 76390 sec after trigger time at 2023-03-21 19:59:16 UT, with upper limit up to  17.7 mag. The observations began at zenith distance = 78 deg. The sun  altitude  is -39.5 deg. 

The galactic latitude b =  4 deg., longitude l = 348 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2205279

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   76480 | 2023-03-21 19:59:16 |         MASTER-SAAO | (16h 32m 24.24s , -47d 25m 16.2s) |   C |   180 | 17.7 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB230320B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33499
SUBJECT: GRB 230320B: Swift/BAT-GUANO detection outside the coded FOV
DATE:    23/03/21 23:43:53 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>

Samuele Ronchini (PSU), Gayathri Raman (PSU), Jamie A. Kennea (PSU),
James DeLaunay (UAlabama), Aaron Tohuvavohu (U Toronto) report:

Swift/BAT did not localize GRB 230320B onboard (T0:
2023-03-20T21:12:25 UTC, Fermi/GBM trig 701039550, CALET trig
1363381768, GECAM trig 163, AstroSat/CZTI GCN 33492).

The Fermi, CALET and GECAM notices, distributed in near real-time,
triggered the Swift Mission Operations Center operated Gamma-ray
Urgent Archiver for Novel Opportunities (GUANO; Tohuvavohu et al.
2020, ApJ, 900, 1).

Upon trigger by this notice, GUANO sent a command to the Swift Burst
Alert Telescope (BAT) to save 200 seconds of BAT event-mode data from
[-50,+150] seconds around the time of the burst. All the requested
event mode data was delivered to the ground.

The BAT likelihood search, NITRATES (DeLaunay + Tohuvavohu 2022, ApJ,
941, 169), detects the burst with a sqrt(TS) of 12.04 in a 4.096 s
analysis time bin.
The Fermi/GBM localization is consistent with being outside the BAT FOV.

See Section 9.1 and Figures 10 and 17 in the NITRATES paper for brief
descriptions and interpretation of sqrt(TS), DeltaLLHPeak, and
DeltaLLHOut.

GUANO is a fully autonomous, extremely low latency, spacecraft
commanding pipeline designed for targeted recovery of BAT event mode
data around the times of compelling astrophysical events to enable
more sensitive GRB searches.

A live reporting of Swift/BAT event data recovered by GUANO can be
found at: https://www.swift.psu.edu/guano/


GRB_name: GRB230320B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33501
SUBJECT: GRB 230320B: CALET Gamma-Ray Burst Monitor detection
DATE:    23/03/22 04:03:08 GMT
FROM:    Yuta Kawakubo at Louisiana State U./CALET  <kawakubo1@lsu.edu>

T. Tamura (Kanagawa U), A. Yoshida, T. Sakamoto, S. Sugita (AGU), 
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), 
Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U),
Y. Shimizu (Kanagawa U), N. Cannady (GSFC/UMBC),
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long GRB 230320B (AstroSat CZTI detection: Navaneeth
et al., GCN Circ 33492) triggered the CALET Gamma-ray Burst 
Monitor (CGBM) at 21:12:22.70 UTC on 20 March 2023
(http://cgbm.calet.jp/cgbm_trigger/flight/1363381768/index.html).
The burst signal was seen by only the SGM detector.

The burst light curve shows a single pulse that starts
at T+2.4 sec, peaks at T+3.5 sec, and ends at T+20.3 sec.
The T90 and T50 durations measured by the SGM data are 16.5 +/- 4.0 sec
and 5.0 +/- 1.0 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1363381768/

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.


GRB_name: GRB230321A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33502
SUBJECT: GRB 230321A: CALET Gamma-Ray Burst Monitor detection
DATE:    23/03/22 04:07:36 GMT
FROM:    Yuta Kawakubo at Louisiana State U./CALET  <kawakubo1@lsu.edu>

N. Cannady (GSFC/UMBC), A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), 
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long GRB 230321A (Fermi GBM Final Real-time Localization: 
Fermi GBM team, GCN Circ. 33490; BALROG localization: Kunzweiler et al.,
GCN Circ 33491) triggered the CALET Gamma-ray Burst Monitor (CGBM)
at 04:21:42.09 UTC on 21 March 2023
(http://cgbm.calet.jp/cgbm_trigger/flight/1363407527/index.html).
The burst signal was seen by all CGBM detectors.

The burst light curve shows a multi-peaked structure that starts
at T+1.0 sec, peaks at T+31.9 sec, and ends at T+86.6 sec.
The T90 and T50 durations measured by the SGM data are 75.5 +/- 1.2 sec
and 35.4 +/- 3.1 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1363407527/

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.


GRB_name: GRB230320B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33503
SUBJECT: GRB 230320B: GRBAlpha detection
DATE:    23/03/22 16:38:18 GMT
FROM:    Marianna Dafcikova at Masaryk University  <500025@mail.muni.cz>

M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner
(Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak
(Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, J.-P.
Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal,  A. Povalac (Brno U.
of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo,
M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U.
of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H.
Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos
U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G.
Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi
(Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss
(Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.),
H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima
U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U.
Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.

The long-duration GRB 230320B (AstroSat/CZTI detection: GCN 33492;
Swift/BAT-GUANO detection: GCN 33499; CALET/CGBM detection: GCN 33501;
Fermi/GBM detection: trigger no. 701039550; GECAM-B detection: trigger no.
163; Konus/Wind detection at 2023-03-20 21:12:25.277 UT) was observed by
the GRBAlpha 1U CubeSat (Pal et al. Proc. SPIE 2020).

The detection was confirmed at the peak time 2023-03-20 21:12:27 UTC. The
T90 duration measured by GRBAlpha is 26 s and the overall significance
during T90 reaches 22.5 sigma.

The light curve obtained by GRBAlpha is available here:
https://grbalpha.konkoly.hu/static/share/GRB230320B_GCN.pdf

All GRBAlpha detections are listed at:
https://monoceros.physics.muni.cz/hea/GRBAlpha/

GRBAlpha, launched on 2021 March 22, is a demonstration mission for a
future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector
of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a
SiPM array, covering the energy range from ~50 keV to ~1000 keV. To
increase the duty cycle and the downlink rate, the upgrade of the on-board
data acquisition software stack is in progress. The ground segment is also
supported by the radio amateur community and it takes advantage of the
SatNOGS network for increased data downlink volume.


GRB_name: GRB230322A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33504
SUBJECT: GRB 230322A: Fermi GBM Final Real-time Localization
DATE:    23/03/22 21:08:07 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 20:57:41 UT on 22 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230322A (trigger 701211466.278488 / 230322873).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 12.3, Dec = 30.7 (J2000 degrees, equivalent to J2000 00h 49m, 30d 41'), with a statistical uncertainty of 7.3 degrees.

The angle from the Fermi LAT boresight is 100.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230322873/quicklook/glg_skymap_all_bn230322873.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230322873/quicklook/glg_healpix_all_bn230322873.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230322873/quicklook/glg_lc_medres34_bn230322873.gif


GRB_name: GRB230322B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33505
SUBJECT: GRB 230322B: Swift detection of a burst with optical counterpart
DATE:    23/03/22 21:25:32 GMT
FROM:    Kim Page at U.of Leicester  <kimlpage1978@gmail.com>

S. B. Cenko (GSFC), J.D. Gropp (PSU), J. A. Kennea (PSU),
N. P. M. Kuin (UCL-MSSL), S. Laha (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), M. J. Moss (GWU), K. L. Page (U Leicester)
and M. A. Williams (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 21:10:37 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 230322B (trigger=1161127).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 16.565, -47.729 which is 
   RA(J2000) = 01h 06m 16s
   Dec(J2000) = -47d 43' 42"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex
structure with a duration of about ~30 sec.  The peak count rate
was ~900 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 21:12:31.7 UT, 113.8 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 16.55359, -47.70106
which is equivalent to:
   RA(J2000)  = 01h 06m 12.86s
   Dec(J2000) = -47d 42' 03.8"
with an uncertainty of 1.9 arcseconds (radius, 90% containment). This
location is 104 arcseconds from the BAT onboard position, within the
BAT error circle. This position may be improved as more data are
received; the latest position is available at
https://www.swift.ac.uk/sper.  We cannot determine whether the source
is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (2.48 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.5
(+2.99/-2.59) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 118 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 01:06:12.85 =  16.55353
  DEC(J2000) = -47:42:02.8  = -47.70079
with a 90%-confidence error radius of about 0.62 arc sec. This position is 0.7
arc sec. from the center of the XRT error circle. The estimated magnitude is
17.60 with a 1-sigma error of about  0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.017. 

Burst Advocate for this burst is S. B. Cenko (brad.cenko AT nasa.gov). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)


GRB_name: GRB230322B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33506
SUBJECT: Swift GRB 230322B: Global MASTER-Net observations report 
DATE:    23/03/23 03:40:29 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB 230322B ( S. B. Cenko et al., GCN 33505) errorbox  22856 sec after notice time and 22880 sec after trigger time at 2023-03-23 03:31:58 UT, with upper limit up to  15.7 mag. Observations started at twilight.  The observations began at zenith distance = 85 deg. The sun  altitude  is -15.9 deg. 

The galactic latitude b = -69 deg., longitude l = 295 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2205479

We obtain a following upper limits.  

Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   22970 |         MASTER-SAAO |   C |   180 | 15.7 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB230322B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33507
SUBJECT: GRB 230322B: Enhanced Swift-XRT position
DATE:    23/03/23 03:49:17 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 957 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 230322B, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 16.55333, -47.70077 which is equivalent
to:

RA (J2000): 01h 06m 12.80s
Dec (J2000): -47d 42' 02.8"

with an uncertainty of 2.3 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB230322B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33508
SUBJECT: GRB 230322B: Swift-XRT refined Analysis
DATE:    23/03/23 06:31:41 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

J. D. Gropp (PSU), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester), A.P. Beardmore (U. Leicester), B. Sbarufatti (INAF-OAB), A.
D'Ai (INAF-IASFPA), A. Melandri (INAF-OAR), S. Dichiara (PSU), J.A.
Kennea (PSU) and S.B. Cenko report on behalf of the Swift-XRT team:

We have analysed 7.8 ks of XRT data for GRB 230322B (Cenko et al. GCN
Circ. 33505), from 123 s to 24.7 ks after the  BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position
for this burst was given by Evans et al. (GCN Circ. 33507).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.61 (+/-0.05).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.09 (+0.21, -0.19). The
best-fitting absorption column is  8.7 (+5.1, -4.4) x 10^20 cm^-2, in
excess of the Galactic value of 2.5 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.1 x 10^-11 (3.8 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      8.7 (+5.1, -4.4) x 10^20 cm^-2
Galactic foreground: 2.5 x 10^20 cm^-2
Excess significance: 2.3 sigma
Photon index:      2.09 (+0.21, -0.19)

If the light curve continues to decay with a power-law decay index of
0.61, the count rate at T+24 hours will be 0.015 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.8 x
10^-13 (5.9 x 10^-13) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01161127.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB230304B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33509
SUBJECT: Konus-Wind detection of GRB 230304B
DATE:    23/03/23 13:08:58 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, D. Frederiks, M. Ulanov, A. Tsvetkova,
A. Lysenko, A. Ridnaia, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration GRB 230304B
(Fermi-GBM detection: the Fermi GBM team, GCN Circ. 33396;
GRBAlpha detection: Dafcikova et al., GCN Circ. 33398;
AstroSat-CZTI detection: Navaneeth et al., GCN Circ. 33400;
CALET-GBM detection: Kobayashi et al., GCN Circ. 33423;
IPN triangulation: Kozyrev et al., GCN Circ. 33480)
triggered Konus-Wind at T0=52553.382 s UT (14:35:53.382).

The burst light curve shows a multi-peaked structure
which starts at ~T0 and has a total duration of ~53 s.
The emission is seen up to ~6 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB230304_T52553/

As observed by Konus-Wind, the burst
had a fluence of 4.57(-0.41,+0.60)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+0.560 s,
of 1.21(-0.18,+0.18)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+40.448 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -1.05(-0.09,+0.09),
the high energy photon index beta = -3.34(-6.66,+0.68),
the peak energy Ep = 299(-28,+32) keV
(chi2 = 68/82 dof).

The spectrum near the maximum count rate
(measured from T0 to T0+7.680 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.89(-0.08,+0.09)
and Ep = 352(-27,+31) keV (chi2 = 91/83 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -3.2
(chi2 = 91/82 dof).

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.


GRB_name: GRB230308A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33510
SUBJECT: Konus-Wind detection of GRB 230308A
DATE:    23/03/23 13:12:16 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, D. Frederiks, M. Ulanov, A. Tsvetkova,
A. Lysenko, A. Ridnaia, and T. Cline
on behalf of the Konus-Wind team, report:

The short-duration GRB 230308A
(Fermi-GBM detection: the Fermi GBM team, GCN Circ. 33420;
Malacaria et al., GCN Circ. 33440;
BALROG localization: Kunzweiler et al., GCN Circ. 33421;
AGILE-MCAL detection: Casentini et al., GCN Circ. 33435;
CALET-GBM detection: Shimizu et al., GCN Circ. 33452;
IPN triangulation: Kozyrev et al., GCN Circ. 33477)
triggered Konus-Wind at T0=48749.809 s UT (13:32:29.809).

The burst light curve shows a multi-peaked structure
which starts at ~T0 and has a total duration of ~0.6 s.
The emission is seen up to ~4 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB230308_T48749/

As observed by Konus-Wind, the burst
had a fluence of 1.31(-0.14,+0.16)x10^-5 erg/cm2,
and a 16-ms peak flux, measured from T0-2 ms,
of 8.03(-1.52,+1.61)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+0.256 s)
is best fit in the 20 keV - 4 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.29(-0.14,+0.17),
the high energy photon index beta = -3.22(-6.78,+0.76),
the peak energy Ep = 936(-162,+161) keV
(chi2 = 47/45 dof).

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.


GRB_name: GRB230309A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33511
SUBJECT: Konus-Wind detection of GRB 230309A
DATE:    23/03/23 13:14:16 GMT
FROM:    Anna Ridnaia at Ioffe Institute  <ridnaia@mail.ioffe.ru>

A. Ridnaia, D. Frederiks, A. Lysenko, D. Svinkin,
A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The long-duration GRB 230309A
(AstroSat CZTI detection: Waratkar et al., GCN Circ. 33464;
IPN triangulation: Kozyrev et al., GCN Circ. 33484)
triggered Konus-Wind at T0=45138.667 s UT (12:32:18.667).

The burst light curve shows a multipeaked structure
which starts at ~T0-6.1 s and has a total duration of ~68.9 s.
The emission is seen up to ~4 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB230309_T45138/

As observed by Konus-Wind, the burst
had a fluence of 1.69(-0.11,+0.12)x10^-4 erg/cm2,
and a 64-ms peak flux, measured from T0+3.232 s,
of 3.12(-0.39,+0.40)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+62.976 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.80(-0.07,+0.08),
the high energy photon index beta = -2.27(-0.15,+0.11),
the peak energy Ep = 305(-25,+29) keV
(chi2 = 96/97 dof).

The spectrum near the maximum count rate
(measured from T0+2.816 to T0+3.584 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.55(-0.10,+0.12),
the high energy photon index beta = -2.80(-0.63,+0.31),
the peak energy Ep = 483(-64,+66) keV
(chi2 = 57/55 dof).

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.


GRB_name: GRB230322B
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33512
SUBJECT: GRB 230322B: Swift/UVOT Detection
DATE:    23/03/23 13:58:42 GMT
FROM:    Samantha Oates at MSSL  <samantha.oates@alumni.ucl.ac.uk>

S. R. Oates (U. of Birmingham) and S. B. Cenko (GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 230322B
119 s after the BAT trigger (Cenko et al., GCN Circ. 33505).
A source consistent with the XRT position
(Evans et al. GCN Circ. 33507)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  01:06:12.84 =  16.55350 (deg.)
    Dec (J2000) = -47:42:02.8  = -47.70079 (deg.)
with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).

Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white              119          269          147         17.60 +/- 0.04
v                  661         1061           58        >18.3
b                  758          778           19         18.55 +/- 0.36
u                  332          581          246         17.63 +/- 0.08
w1                 710         1095           19         16.90 +/- 0.28
m2                1064         1084           19         17.17 +/- 0.35
w2                 635          655           19         17.36 +/- 0.32

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.017 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB230320B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33515
SUBJECT: GRB 230320B: Fermi GBM Observation
DATE:    23/03/24 21:32:11 GMT
FROM:    Sarah Dalessi at UAH  <sd0104@uah.edu>

S. Dalessi (UAH), C. Fletcher (USRA) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 21:12:25 UT on 20 March 2023, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 230320B (trigger 701039550/230320884).
which was also detected by AstroSat (P K. Navaneeth et al. 2023, GCN
33492), Swift/BAT-GUANO (S. Ronchini et al. 2023, GCN 33499) CALET (T.
Tamura et al. 2023, GCN 33501), and GRBAlpha (M. Dafcikova et al.
2023, GCN 33503).

The on-ground calculated location, using the GBM trigger
data, is RA = 28.11, DEC = 68.88 (J2000 degrees,
equivalent to 01 h 52 m,  68 d 53â€™ ), with a statistical uncertainty
of 2.6 degrees (radius, 1-sigma containment,
statistical only; there is additionally a systematic
error which we have characterized as a core-plus-tail model, with 90% of
GRBs having a 3.7 deg error and a small tail suffering a larger than 10 deg
systematic error. [Connaughton et al. 2015, ApJS, 216, 32] ).

The angle from the Fermi LAT boresight is 140 degrees.

The GBM light curve consists of a single emission episode with a duration (T90)
of about 15 s (50-300 keV). The time-averaged spectrum
from T0+0.003 to T0+15.616 s is best fit by a power law function with
an exponential
high-energy cutoff.The power law index is -0.30 +/- 0.09 and
the cutoff energy, parameterized as Epeak = 186 +/- 8 keV.

The event fluence (10-1000 keV) in this time interval is
(1.02 +/- 0.03)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0 s in the 10-1000 keV band is 12.7 +/- 0.6 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB230325A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33516
SUBJECT: GRB 230325A: Swift detection of a burst
DATE:    23/03/25 03:27:21 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

M. J. Moss (GWU), N. P. M. Kuin (UCL-MSSL), S. Laha (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester),
D. M. Palmer (LANL) and A. Tohuvavohu (U Toronto) report on behalf of
the Neil Gehrels Swift Observatory Team:

At 03:15:35 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 230325A (trigger=1161390).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 296.820, -46.094 which is 
   RA(J2000) = 19h 47m 17s
   Dec(J2000) = -46d 05' 38"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex structure
structure with a duration of about 40 sec.  The peak count rate
was ~2200 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 03:17:09.9 UT, 94.0 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source located at RA, Dec 296.84910,
-46.07455 which is equivalent to:
   RA(J2000)  = 19h 47m 23.78s
   Dec(J2000) = -46d 04' 28.4"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 100 arcseconds from the BAT onboard position, within the
BAT error circle. This position may be improved as more data are
received; the latest position is available at
https://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (4.88 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.9
(+3.24/-2.71) x 10^21 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 2.06e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 101 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. The list of sources is typically complete to about 18 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.046. 

Burst Advocate for this burst is M. J. Moss (mikejmoss3 AT gmail.com). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)


GRB_name: GRB230325A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33517
SUBJECT: GRB 230325A: Prompt enhanced Swift-XRT position
DATE:    23/03/25 03:40:21 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:

Using  promptly downlinked XRT event data for GRB 230325A, we find an
enhanced XRT position of the afterglow: RA, Dec: 296.84935, -46.07561
which is equivalent to:
   RA (J2000)  = 19 47 23.85
   Dec (J2000) = -46 04 32.2
with an uncertainty of 1.9 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/1161390.

Position enhancement is is described by Goad et al. (2007, A&A, 476,
1401) and Evans et al. (2009, MNRAS, 397, 1177).

This circular is an official product of the Swift-XRT team.


GRB_name: GRB230325A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33518
SUBJECT: GRB 230325A: Enhanced Swift-XRT position
DATE:    23/03/25 05:58:39 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

M.R. Goad, J.P. Osborne, A.P. Beardmore and P.A. Evans (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 290 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 230325A, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 296.84984, -46.07613 which is equivalent
to:

RA (J2000): 19h 47m 23.96s
Dec (J2000): -46d 04' 34.1"

with an uncertainty of 2.3 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB230322B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33519
SUBJECT: GRB 230322B: Swift-BAT refined analysis
DATE:    23/03/25 17:01:17 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

S. Laha (GSFC/UMBC), S. D. Barthelmy (GSFC),
S. B. Cenko (GSFC), H. A. Krimm (NSF),
A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC),
T. Sakamoto (AGU), M. Stamatikos (OSU)
(i.e. the Swift-BAT team):

Using the data set from T-826 to T+962 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 230322B (trigger #1161127)
(Cenko et al., GCN Circ. 33505).  The BAT ground-calculated position is
RA, Dec = 16.550, -47.709 deg which is
   RA(J2000)  =  01h 06m 12.1s
   Dec(J2000) = -47d 42' 31.2"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 92%.

The mask-weighted light curve shows a single-peaked FRED-like structure
that starts at ~T-3 s, peaks at ~T0, and ends at ~T+11 s.
T90 (15-350 keV) is 11.61 +- 2.17 sec (estimated error including
systematics).

The time-averaged spectrum from T-2.41 to T+11.12 sec is best fit by a
simple
power-law model.  The power law index of the time-averaged spectrum is
2.07 +- 0.26.  The fluence in the 15-150 keV band is 3.7 +- 0.6 x 10^-7
erg/cm2.
The 1-sec peak photon flux measured from T+0.02 sec in the 15-150 keV band
is 1.1 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1161127/BA/


GRB_name: GRB230325A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33520
SUBJECT: GRB 230325A: Swift-XRT refined Analysis
DATE:    23/03/25 19:44:08 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U.
Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAR), T. Sbarrato
(INAF-OAB), S. Dichiara (PSU), J.A. Kennea (PSU), A. Tohuvavohu (U.
Toronto) and M.J. Moss report on behalf of the Swift-XRT team:

We have analysed 7.1 ks of XRT data for GRB 230325A (Moss et al. GCN
Circ. 33516), from 83 s to 45.2 ks after the  BAT trigger. The data
comprise 139 s in Windowed Timing (WT) mode (the first 10 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Goad et al.
(GCN Circ. 33517).

The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=1.1 (+/-0.5). At T+123 s  the decay
steepens to an alpha of 3.24 (+0.27, -0.16) before breaking again at
T+598 s to a final decay with index alpha=0.42 (+/-0.14).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.16 (+0.11, -0.10). The
best-fitting absorption column is  3.2 (+/-0.4) x 10^21 cm^-2, in
excess of the Galactic value of 4.9 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 2.13 (+0.25, -0.23)
and a best-fitting absorption column of 2.5 (+0.9, -0.8) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 3.4 x 10^-11 (5.1 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.5 (+0.9, -0.8) x 10^21 cm^-2
Galactic foreground: 4.9 x 10^20 cm^-2
Excess significance: 4.2 sigma
Photon index:      2.13 (+0.25, -0.23)

If the light curve continues to decay with a power-law decay index of
0.42, the count rate at T+24 hours will be 0.028 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 9.3 x
10^-13 (1.4 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01161390.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB230325A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33521
SUBJECT: GRB 230325A: X-shooter optical afterglow and redshift
DATE:    23/03/25 20:56:07 GMT
FROM:    Daniele B Malesani at Radboud U  <d.malesani@astro.ru.nl>

Danielle Pieterse (Radboud Univ.), Johan P. U. Fynbo (DAWN/NBI), Luca 
Izzo (DARK/NBI), Jesse Palmerio (GEPI, Obs. Paris and IAP), Andrea 
Saccardi (GEPI, Obs. Paris), Nial R. Tanvir (Leicester), Dong Xu 
(NAO/CAS), Zi-Pei Zhu (NAOC, HUST), Daniele B. Malesani (Radboud univ. 
and DAWN/NBI) and Pall Jakobsson (Univ. Iceland), report on behalf of 
the Stargate collabaration:

We observed the field of GRB 230325A (Moss et al., GCN 33516) using the 
ESO VLT UT3 (Melipal) equipped with the X-shooter spectrograph. Images 
were also taken with the acquisition camera. An object is visible 
consistent with the UVOT-enhanced XRT position (Goad et al., GCN 33518), 
at coordinates (0.5" error):

RA = 19:47:23.98  (J2000)
Dec = -46:04:33.3  (J2000)

For this object, we measure the following magnitudes (calibrated against 
nearby objects from the Legacy Survey; Dey et al. 2019, AJ, 157, 168):

Filter Mean date        Time since GRB  Exptime  Magnitude
         (UT)             (days)          (s)      (AB)
--------------------------------------------------------------
r      2023 Mar 25.371  0.235           45       22.70 +- 0.08
z      2023 Mar 25.372  0.236           60       22.35 +- 0.08
g      2023 Mar 25.374  0.237           45       22.16 +- 0.23

An object is present at a consistent location in the Legacy Survey, but 
significantly fainter, and it is the likely GRB host galaxy. The 
consistency with the XRT position and the flux increase compared to the 
Legacy Survey confirm that the object we see in the X-shooter images is 
the optical afterglow of GRB 230325A.


Spectroscopy was carried out, covering the wavelength range 3000-21000 
AA, and consisting of 2 exposures by 600 s each. The observation mid 
time was 2023 Mar 25.383 UT (0.247 days after the GRB).

Only a faint continuum is detected from this source, which allows us to 
set a redshift upper limit z <~ 3. In addition, two emission lines are 
visible, which are consistent with Halpha and [O III] 5008 at a common 
redshift z = 1.664, which we suggest to be the GRB redshift.

We acknowledge excellent support from the ESO observing staff in 
Paranal, in particular Fuyan Bian and Konrad Tristram.


GRB_name: GRB230325A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33522
SUBJECT: GRB 230325A: Swift/UVOT Upper Limits
DATE:    23/03/26 15:23:20 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

N Paul Kuin (UCL/MSSL) and M. J. Moss (GWU)report on behalf
of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of
GRB 230325A 102 s after the BAT trigger (Moss et al., GCN
Circ. 33516).   No optical afterglow consistent with the
XRT position (Goad et al. GCN Circ. 33518) is detected in
the initial UVOT exposures. Preliminary 3-sigma upper
limits using the UVOT photometric system (Breeveld et al.
2011, AIP Conf. Proc. 1358, 373) for the first finding
chart (FC) exposure and subsequent exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC           102          252          147         >20.1
u_FC               314          540          222         >19.2
white              102         4222          344         >20.8
v                 4434         4634          197         >18.9
b                 3818         4018          197         >20.0
u                  314         5106          277         >19.3
w1                4845         5045          197         >19.9
m2                4640         4839          197         >19.8
w2                4230         4429          197         >20.2
The magnitudes in the table are not corrected for the Galactic
extinction due to the reddening of E(B-V) = 0.046 in the
direction of the burst (Schlegel et al. 1998).


GRB_name: GRB230325A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33523
SUBJECT: GRB 230325A: Swift-BAT refined analysis
DATE:    23/03/26 15:38:17 GMT
FROM:    Hans Krimm at NSF/NASA-GSFC  <hkrimm@nsf.gov>

A. Y. Lien (U Tampa), S. D. Barthelmy (GSFC), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), C. B. Markwardt (GSFC), M. J. Moss (GWU),
D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU),
M. Stamatikos (OSU) (i.e. the Swift-BAT team):

Using the data set from T-240 to T+962 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 230325A (trigger #1161390)
(Moss, et al., GCN Circ. 33516).  The BAT ground-calculated position is
RA, Dec = 296.854, -46.067 deg which is
   RA(J2000)  =  19h 47m 24.9s
   Dec(J2000) = -46d 03' 59.8"
with an uncertainty of 1.5 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 48%.

The mask-weighted light curve shows a main pulse with a FRED shape, from
approximately T+0 to T+8 seconds.  This is preceded by some precursor emission
starting around T-10 sec, and some low-level emission out to about T+40 sec.
The spacecraft slewed away from the burst location around T+620 seconds.
T90 (15-350 keV) is 38.05 +- 11.56 sec (estimated error including systematics).

The time-averaged spectrum from T-8.55 to T+41.70 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.82 +- 0.18.  The fluence in the 15-150 keV band is 1.3 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-0.07 sec in the 15-150 keV band
is 3.3 +- 0.4 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1161390/BA/


GRB_name: GRB230328A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33524
SUBJECT: GRB 230328A: Fermi GBM Final Real-time Localization
DATE:    23/03/28 14:08:58 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 13:58:24 UT on 28 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230328A (trigger 701704709.245818 / 230328582).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 196.8, Dec = 1.1 (J2000 degrees, equivalent to J2000 13h 07m, 1d 06'), with a statistical uncertainty of 8.4 degrees.

The angle from the Fermi LAT boresight is 47.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230328582/quicklook/glg_skymap_all_bn230328582.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230328582/quicklook/glg_healpix_all_bn230328582.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230328582/quicklook/glg_lc_medres34_bn230328582.gif


GRB_name: GRB230328A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33525
SUBJECT: Fermi GRB 230328A: Global MASTER-Net observations report 
DATE:    23/03/28 14:30:11 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-Amur robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Blagoveshchensk State Pedagogical University) started inspect of the Fermi GRB 230328A ( Fermi GBM team, GCN 33524) errorbox  826 sec after notice time and 888 sec after trigger time at 2023-03-28 14:13:13 UT, with upper limit up to  12.7 mag. The observations began at zenith distance = 57 deg. The sun  altitude  is -34.2 deg. 

The galactic latitude b = 63 deg., longitude l = 313 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2206584

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

     919 | 2023-03-28 14:13:13 |         MASTER-Amur | (13h 17m 43.55s , +01d 05m 59.6s) |   C |    60 | 12.7 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB230328B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33526
SUBJECT: GRB 230328B: Fermi GBM Final Real-time Localization
DATE:    23/03/28 15:05:06 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 14:54:47 UT on 28 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230328B (trigger 701708092.430074 / 230328621).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 301.8, Dec = 75.6 (J2000 degrees, equivalent to J2000 20h 07m, 75d 35'), with a statistical uncertainty of 3.2 degrees.

The angle from the Fermi LAT boresight is 38.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230328621/quicklook/glg_skymap_all_bn230328621.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230328621/quicklook/glg_healpix_all_bn230328621.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230328621/quicklook/glg_lc_medres34_bn230328621.gif


GRB_name: GRB230328B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33527
SUBJECT: GRB 230328B: Swift detection of a burst with an optical afterglow
DATE:    23/03/28 15:06:35 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

J.D. Gropp (PSU), S. Dichiara (PSU),
R. A. J. Eyles-Ferris (U Leicester), N. P. M. Kuin (UCL-MSSL),
F. E. Marshall (NASA/GSFC), M. J. Moss (GWU),
K. L. Page (U Leicester), D. M. Palmer (LANL) and M. H. Siegel (PSU)
report on behalf of the Neil Gehrels Swift Observatory Team:

At 14:54:48 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 230328B (trigger=1162001).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 290.986, +80.016 which is 
   RA(J2000) = 19h 23m 57s
   Dec(J2000) = +80d 00' 58"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex GRB
structure with a duration of about 20 sec, followed by a bright flaring
afterglow visible below 25 keV for at least 200 s.  The peak count rate
was ~4375 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 14:56:38.8 UT, 110.3 seconds after
the BAT trigger. Using promptly downlinked data we find a fading,
uncatalogued X-ray source located at RA, Dec 291.00418, 80.00951 which
is equivalent to:
   RA(J2000)  = 19h 24m 01.00s
   Dec(J2000) = +80d 00' 34.2"
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This
location is 25 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at https://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (6.28 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.6
(+1.76/-1.56) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 114 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 19:24:01.84 = 291.00765
  DEC(J2000) = +80:00:34.5  =  80.00959
with a 90%-confidence error radius of about 0.62 arc sec. This position is 0.7
arc sec. from the center of the XRT error circle. The estimated magnitude is
18.22 with a 1-sigma error of about  0.15. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.070. 

Burst Advocate for this burst is J.D. Gropp (jdg44 AT psu.edu). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)


GRB_name: GRB230328B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33528
SUBJECT: GRB 230328B: Mondy optical afterglow confirmation
DATE:    23/03/28 16:31:55 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

N. Pankov (HSE), E. Klunko (ISTP), A. Pozanenko (IKI), S. Belkin (IKI) 
report on behalf of GRB IKI FuN:

We observed  the field of Swift GRB 230328B (Gropp et al. GCN 33527) 
with AZT-33IK telescope of Mondy observatory  in  R-filter on
2023-03-28 starting (UT) 15:27:18. We clearly detect the optical 
afterglow of GRB 230328B (Gropp et al. GCN 33527) at the position of 
(J2000) 19 24 01.828 +80 00 34.53 with an error of 0.5 arcsec in both 
coordinates, which coincides with the position of UVOT (Gropp et al. GCN 
33527).

Preliminary photometry  of a stack of the first 5 images is following

Date       UT start  t-T0     Exp.  Filter   OT     Err.  UL(3sigma)
                    (mid, days)  (s)

2023-03-28  15:27:18   0.026047 5*60 R        18.9  0.2   21.1

The photometry is based on nearby USNO-B1.0 stars.


GRB_name: GRB230328B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33529
SUBJECT: GRB 230328B: Enhanced Swift-XRT position
DATE:    23/03/28 19:00:09 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

J.P. Osborne, A.P. Beardmore, P.A. Evans and M.R. Goad (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 1128 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 230328B, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 291.00713, +80.00952 which is equivalent
to:

RA (J2000): 19h 24m 1.71s
Dec (J2000): +80d 00' 34.3"

with an uncertainty of 2.1 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB230328B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33530
SUBJECT: GRB 230328B: Mondy, AbAO and Kitab optical observations
DATE:    23/03/28 21:40:25 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Belkin (IKI), R. Ya. Inasaridze (AbAO), E. Klunko (ISTP), A. 
Novichonok (Petrozavodsk State University, KIAM), A. Pozanenko (IKI), N. 
Pankov (HSE, IKI), D. Datashvili (AbAO), V. R. Ayvazian (AbAO),  G. V. 
Kapanadze (AbAO)  report on behalf of GRB IKI FuN:

We observed the field of Swift GRB 230328B (Gropp et al. GCN 33527; 
Osborne et al. GCN 33529) till now  with AZT-33IK telescope of Mondy 
observatory  in  R-filter, RC-36 telescope of Kitab observatory in 
Clear, AS-32 telescope of Abastumani observatory in R-filter. The 
optical afterglow (Gropp et al. GCN 33527; Pankov et al. GCN 33528) is 
detected in Mondy and Abastumani, and not detected in Kitab observatory.

Preliminary photometry  of a stacked  images is following


Date       UT start   t-T0    Filter Exp.    OT    Err.  UL(3sigma)
                       (mid, days)    (s)

2023-03-28  16:19:20  0.062188  R      5*120    19.34  0.10   21.0
2023-03-28  16:37:07  0.042338  Clear 19*60     n/d    n/d    17.6
2023-03-28  16:15:48  0.086725  R    104*60     19.50  0.10   21.2


The photometry is based on nearby USNO-B1.0 stars.

Approximation of above photometry in R-filter and photometry reported 
early (GCN 33528) results in the power law index of -0.45 of slow decay 
LC of GRB 230328B.


GRB_name: GRB230328B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33531
SUBJECT: GRB 230328B: Fermi GBM observation
DATE:    23/03/28 22:50:25 GMT
FROM:    Sarah Dalessi at UAH  <sd0104@uah.edu>

S. Dalessi (UAH) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 14:54:47.43 UT on 28 March 2023, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 230328B (trigger 701708092 / 230328621),
which was also detected by the Swift/BAT (J.D. Gropp et al. 2023, GCN 33527)
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 38 degrees.

The GBM light curve consists of a single burst
with a duration (T90) of about 19 s (50-300 keV).
The time-averaged spectrum from T0-3.5 s to T0+19.1 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -1.16 +/- 0.03 and
the cutoff energy, parameterized as Epeak, is 169.6 +/- 9.9 keV.

The event fluence (10-1000 keV) in this time interval is
(9.4 +/- 0.3)E-06 erg/cm^2. The 1 sec peak photon flux measured
starting from T0+1.4 s in the 10-1000 keV band
is 12.7 +/- 0.3 ph/s/cm^2.

A Band function fits the spectrum equally well with Epeak = 125.0 +/- 11.3 keV,
alpha = -1.03 +/- 0.06, and beta = -2.10+/- 0.09.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB230328B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33532
SUBJECT: GRB 230328B: AstroSat CZTI detection
DATE:    23/03/29 01:58:51 GMT
FROM:    Varun Bhalerao at Indian Inst of Tech  <varunb@iitb.ac.in>

G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of GRB 230328B which was also detected by Fermi-GBM (GCN Circ. 33526), Swift-BAT (Gropp et. al, GCN Circ. 33527). 

The source was clearly detected in the 20-200 keV energy range. The light curve peaks at 2023-03-28 14:54:49.5 UTC. The measured peak count rate associated with the burst is 244.7 (+41.3 -43.3) counts/s above the background in the combined data of all quadrants, with a total of 1090 (+249 -250) counts. The local mean background count rate was 409.1 (+2.4 -3.1) counts/s. Using cumulative rates, we measure a T90 of 11.78 (+4.17 -4.51) s.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2023-03-28 14:54:48.3 UTC. The measured peak count rate is 561.0 (+68.3 -74.6) counts/s above the background in the combined Veto data of all quadrants, with a total of 2819 (+428 -485) counts. The local mean background count rate was 1299.3 (+5.2 -5.5) counts/s. We measure a T90 of 12.86 (+5.41 -4.68) s from the cumulative Veto light curve.

CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at: http://astrosat.iucaa.in/czti/?q=grb 


GRB_name: GRB230328B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33533
SUBJECT: GRB 230328B: Swift-XRT refined Analysis
DATE:    23/03/29 03:11:19 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), A. Melandri
(INAF-OAR), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), J.A. Kennea
(PSU), A. Tohuvavohu (U. Toronto), D.N. Burrows (PSU), J.P. Osborne (U.
Leicester) and J.D. Gropp report on behalf of the Swift-XRT team:

We have analysed 9.2 ks of XRT data for GRB 230328B (Gropp et al. GCN
Circ. 33527), from 94 s to 28.9 ks after the  BAT trigger. The data
comprise 9 s in Windowed Timing (WT) mode (taken while Swift was
slewing), with the remainder in Photon Counting (PC) mode. The enhanced
XRT position for this burst was given by Osborne et al. (GCN Circ.
33529).

The late-time light curve (from T0+4.3 ks) can be modelled with a
power-law decay with a decay index of alpha=1.06 (+/-0.07).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.89 (+/-0.08). The
best-fitting absorption column is  1.37 (+0.26, -0.24) x 10^21 cm^-2,
in excess of the Galactic value of 6.3 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.6 x 10^-11 (4.5 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.37 (+0.26, -0.24) x 10^21 cm^-2
Galactic foreground: 6.3 x 10^20 cm^-2
Excess significance: 5.1 sigma
Photon index:      1.89 (+/-0.08)

If the light curve continues to decay with a power-law decay index of
1.06, the count rate at T+24 hours will be 0.052 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.9 x
10^-12 (2.3 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01162001.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB230328B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33534
SUBJECT: GRB 230328B: Nanshan/NEXT optical upper limit
DATE:    23/03/29 03:45:19 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

T.H. Lu, S.Q. Jiang, S.Y. Fu, X. Liu (NAOC), Z.P. Zhu (NAOC, HUST), D. 
Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:

We observed the field of GRB 230328B detected by Swift (Gropp et al., 
GCN 33527),using the NEXT-0.6m optical telescope located at Nanshan, 
Xinjiang, China. Observations started at 16:39:57 UT on 2023-03-28, 
i.e., 1.75 hr after the Swift/BAT trigger.

The previously reported optical afterglow (e.g., Pankov et al., GCN 
33528; Belkin et al., GCN 33530) is marginally detected in our stacked 
image. Preliminary photometry of the afterglow has r ~ 19.1 mag, 
calibrated by nearby PanSTARRS stars.


GRB_name: GRB230328B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33535
SUBJECT: GRB 230328B: OASDG optical observations
DATE:    23/03/29 08:38:29 GMT
FROM:    Luca Izzo at DARK/NBI  <luca.izzo@gmail.com>

A. Catapano (OASDG), and L. Izzo (DARK/NBI) report:

We observed the field of GRB 230328B (Gropp et al., GCN #33527) with the 0.5m telescope of the Osservatorio Astronomico S. Di Giacomo located in Agerola, Italy ( https://osservatorio.astrocampania.it/ ). We obtained two sets of 8x240s images each in the Rc and in the Ic filter under good weather conditions, with the two sets of observations separated by three hours each.

In the first dataset, we detect a faint source in the stacked Ic images at the enhanced position reported by Swift-XRT (Osborne et al., GCN #33529) and by optical telescopes (Pankov et al., GCN #33528; Belkin et al., GCN #33530, Lu et al., GCN #33534). We measure a preliminary magnitude of ~19.5 mag (AB), at exposure mid-time of MJD 60031.8 (5.1 hours after the GRB detection). We also report an upper limit of ~20.0 mag in the Rc band. In the second set of observations, the source is not detected in both filters, with upper limits of Rc > 20.2, and Ic > 19.8, respectively (MJD 60031.9, 8.1 hours after the GRB). The calibration was performed using nearby stars in the Pan-STARRS PS1 catalog, and using transformation equations to Rc and Ic magnitudes. Further analyses are ongoing.


GRB_name: GRB230328B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33536
SUBJECT: GRB 230328B: GIT optical follow-up
DATE:    23/03/29 14:22:27 GMT
FROM:    Varun Bhalerao at Indian Inst of Tech  <varunb@iitb.ac.in>

A. Suresh (IITB), V. Swain (IITB), H. Kumar (IITB), P. Dorjay (IAO), V. Bhalerao (IITB), G. C. Anupama(IIA), S. Barway (IIA) report on behalf of the GIT team:

We observed GRB 230328B detected by Swift-BAT and optical afterglow discovered by Swift-UVOT (GCN 33527), with the 0.7m GROWTH-India Telescope (GIT). The observations started at 16:51:27.896 UT on 2023-03-28, 116.66 mins after the Swift-BAT trigger. We obtained multiple 300s exposures in the g', r', i', and z' filters. In stacked images for two bands, we clearly detected the afterglow at R.A.= 19h 24m 01.8s, DEC.= 80d 00' 34.5", consistent with the enhanced Swift-XRT position (GCN 33533). The photometric results follow as:
-------------------------------------------------------------------
 JD (mid) | T_mid-T0(hrs) | Filter| Total Exposure (s) | Magnitude (AB) |
-------------------------------------------------------------------
 2460032.22721302 | 2.539 | r'    | 1200 |20.181 +/- 0.054 |
 2460032.23485986 | 2.723 | i'    | 1200 |19.672 +/- 0.078 |
 2460032.23490645 | 2.724 | g'    | 600  |>20.089 |
 2460032.24251012 | 2.906 | z'    | 1200 |>18.503 |
-------------------------------------------------------------------

These magnitudes are consistent with the reported optical afterglow detections (N. Pankov et al., GCN #33528; S. Belkin et al., GCN #33530; T.H. Lu et al., GCN #33534; A. Catapano et al., GCN #33535).

The magnitudes are calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction.

The GROWTH India Telescope (GIT; Kumar et al. 2022) is a 70-cm telescope with a 0.7-degree field of view, set up by the Indian Institute of Astrophysics (IIA) and the Indian Institute of Technology Bombay (IITB) with funding from DST-SERB and IUSSTF. It is located at the Indian  Astronomical Observatory (Hanle), operated by IIA. We acknowledge funding by the IITB alumni batch of 1994, which partially supports operations of the telescope. Telescope technical details are available at https://sites.google.com/view/growthindia/.


GRB_name: GRB230328B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33537
SUBJECT: GRB 230328B: OHP/T120 optical observations
DATE:    23/03/29 14:52:49 GMT
FROM:    Benjamin Schneider at MIT  <bschn@mit.edu>

C. Adami (LAM), B. Schneider (MIT), M. Birlan, T. Hromakina 
(Obs. de Paris), S. Basa (LAM), E. Le Floc'h, D. Turpin, D. GÃ¶tz 
(CEA Paris-Saclay), S. D. Vergani (GEPI, Obs. de Paris), report 
on behalf of a larger collaboration:

We observed the field of GRB 230328B (Gropp et al., GCN 33527; 
Osborne et al., GCN 33529; Dalessi et al., GCN 33531; Waratkar et al.
GCN 33532) using the T120cm telescope at Observatoire de Haute-Provence 
(France). Six exposures were obtained in the Rc band (2x300s + 4x600s) 
from 28 March 2023 18:51:01 UT to 28 March 2023 20:13:46 UT (mid time 
~4.5h after trigger). In the combined frame, we clearly detect the source 
and obtain the following magnitude:

Rc = 20.03 +/- 0.10 mag (AB)

The photometric calibration was performed using nearby stars from 
the PanSTARRS catalog converted in Rc and the magnitude is not 
corrected for Galactic extinction.

The value is consistent with early observations obtained by Pankov et al. 
(GCN 33528), Belkin et al. (GCN 33530) and Lu et al. (GCN 33534), and the 
upper limit reported by Catapano & Izzo (GCN 33535) at a similar epoch.

We acknowledge the excellent support from Observatoire de Haute Provence.


GRB_name: GRB230328B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33538
SUBJECT: GRB 230328B: Liverpool Telescope afterglow detection
DATE:    23/03/29 16:01:52 GMT
FROM:    Ben Gompertz at U of Birmingham  <b.gompertz@bham.ac.uk>

B. P. Gompertz (U. Birmingham), D. B. Malesani (U. Radboud and DAWN/NBI) and A. J. Levan (U. Radboud) report:

We observed GRB 230328B (Fermi GBM Team, GCN 33526; Gropp et al., GCN 33527) with the IO:O optical camera on the 2m robotic Liverpool Telescope. Observations began on March 29, 2023 at 03:20:58 UT (~12.4 hr after the Fermi and Swift triggers) and consist of a series of 15x120 s exposures in each of the SDSS r' and i' filters.

We detect the optical afterglow first reported by Swift-UVOT (Gropp et al. GCN 33527) with the following magnitudes:

r' = 21.16  0.06
i' = 20.75  0.07

Magnitudes are in the AB system, calibrated against nearby PS1 stars (Chambers et al., 2016), and are not corrected for the Galactic reddening of E(B-V) = 0.06 magnitudes along the line of sight (Schlafly & Finkbeiner 2011).


GRB_name: GRB230328B
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33539
SUBJECT: GRB 230328B NUTTelA-TAO / BSTI Early Measurements
DATE:    23/03/29 18:00:30 GMT
FROM:    Toktarkhan Komesh at Nazarbayev University  <toktarkhan.komesh@nu.edu.kz>

T. Komesh (NU), Zh. Maksut (NU), B. Grossan (UCB, NU), Zh. Abdullayev (NU), M. Krugov (FAI), report on behalf of the Energetic Cosmos Laboratory:

The Nazarbayev University Transient Telescope at Assy-Turgen Astrophysical Observatory (NUTTelA-TAO) pointed at GRB230328B on receipt of an automated GCN / BAT position alert, observing in Sloan g', r' and i' bands, with the Burst Simultaneous Three-Channel Imager (BSTI; Grossan, Kumar & Smoot 2019, JHEA, 32, 14).

We started observations at UT 2023-03-28 14:55:23, 41 s after the BAT trigger. Observations were made under clear conditions. A new and changing source consistent with the XRT position (Osborne 2023, GCN 33529) was detected. Note that these observations provide essentially full-time coverage, simultaneous in all three bands. We report the following photometric values for the OT:


tc-t0(s)  g'(mag)   exposure_time (s)                               
--------    -------    --------   
 68       17.1     54
 125     17.1     60       
 185     17.5     60       
 245     17.6     60       
 305     18.0     60       
 365     18.0     60       
 440     18.6     90       
 530     18.8     90       
 620     19.1     90       
 725     19.1     120       
 845     19.8     120       
 965     17.7     120       

 tc-t0(s)    r'(mag)    i'(mag)      exposure_time (s)
------    --------     ------          -------
45       16.5        16.1              7.5
53       16.5        15.9              7.5
60       16.4        16.0              7.5
68       16.8        16.0              7.5
75       16.4        15.9              7.5
83       16.6        16.1              7.5
90       16.5        15.9              7.5
119      16.8        16.1               15
134      16.7        16.2               15
149      16.6        16.2               15
164      17.0        16.3               15
179      16.8        16.3               15
194      17.0        16.3               15
209      16.8        16.6               15
224      17.0        16.8               15
239      17.2        16.7               15
254      17.2        16.8               15
269      17.3        16.7               15
284      17.2        16.8               15
299      17.2        16.9               15
314      17.2        17.1               15
329      17.4        17.1               15
344      17.5        16.9               15
359      17.6        17.3               15
374      17.4        16.9               15
389      17.6        17.6               15
404      17.8        17.1               15
419      17.8        16.9               15
434      17.5        17.1               15
449      17.6        17.3               15
464      17.8        17.4               15
479      17.4        17.0               15
494      18.1        17.1               15
509      17.5        17.3               15
524      17.7        17.1               15
539      18.4        17.5               15
554      17.6        17.2               15
569      17.9        17.7               15
584      18.0        17.2               15
599      17.6        17.6               15
614      17.7        17.4               15
629      17.8        17.5               15
644      17.6        17.2               15
659      17.8        17.5               15
674      17.6        17.6               15
689      18.1        17.3               15
704      18.0        17.5               15
719      17.8        17.5               15
734      17.9        17.5               15
749      18.1        17.3               15
764      18.1        17.3               15
779      18.2        17.8               15
794      18.0        17.6               15
809      18.3        17.5               15
824      18.5        17.5               15
839      18.2        17.4               15
854      18.1        17.4               15
869      18.0        18.4               15
884      17.8        17.8               15
899      18.4        17.8               15
914      18.4        17.1               15
929      17.9        18.1               15
944      17.8        17.3               15
959      18.3        18.3               15
974      18.1        17.1               15
989      18.1        17.9               15
1004     18.3        17.6               15


Uncertainties are estimated at ~ 0.1 mag for all three filters except the latest images of gâ€™ with indications of errors ~ 0.15 mag. tc-t0 = trigger time minus image center time. Calibration was done with 3-4 bright Pan-STARRS catalog stars on our images, and no other analysis or corrections.

We caution the reader that these are preliminary results, without color or other corrections, and will likely change in small measure. Please also note that times are approximate.

----------------------------------
NU = Nazarbayev University, Nur-Sultan, Kazakhstan
UCB = University of California, Berkeley, USA
FAI = Fesenkov Astrophysical Institute, Kazakhstan

This research has been funded by the Science Committee of the Ministry of Science and Higher Education of the Republic of Kazakhstan (Grant No. AP14870504). The NUTTelA-TAO Team acknowledges the support of the staff of the Assy-Turgen Astrophysical Observatory, Almaty, Kazakhstan, and the Fesenkov Astrophysical Institute, Almaty, Kazkhstan.


GRB_name: GRB230328B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33540
SUBJECT: GRB 230328B: Nanshan/NEXT 2nd optical observation
DATE:    23/03/30 01:53:10 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

T.H. Lu, S.Q. Jiang, S.Y. Fu, X. Liu (NAOC), Z.P. Zhu (NAOC, HUST), D. 
Xu (NAOC), X. Gao (Urumqi No.1 Senior High School), J.Z. Liu (XAO) report:

We observed the field of GRB 230328B detected by Swift (Gropp et al., 
GCN 33527) using the NEXT-0.6m telescope located at Nanshan, Xinjiang, 
China. We obtained 12x300 s frames in the Sloan r-band, starting at 
14:49:11 UT on 2023-03-29 (i.e., 23.9 hr after the BAT trigger).

The optical afterglow (e.g., Pankov et al., GCN 33528; Belkin et al., 
GCN 33530; Lu et al., GCN 33534; Catapano et al., GCN 33535; Suresh et 
al., GCN 33536; Adami et al., GCN 33537; Gompertz et al., GCN 33538; 
Komesh et al., GCN 33539) is not detected in our stacked image. 
Preliminary photometric result is as follows:

T_mid-T0 (hr)   Filter   Upper limit(3-sigma)
    24.42             r           >21.0

calibrated with the nearby PanSTARRS field and not corrected for 
Galactic extinction.


GRB_name: GRB230328B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33541
SUBJECT: GRB 230328B: Swift-BAT refined analysis
DATE:    23/03/30 03:44:23 GMT
FROM:    Tyler Parsotan at UMBC/GSFC/CRESST II  <parsotat@umbc.edu>

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), 

H. A. Krimm (NSF), S. Laha (GSFC/UMBC),

A. Y. Lien (U Tampa), D. M. Palmer (LANL),

T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU),

M. Stamatikos (OSU) (i.e. the Swift-BAT team):

 

Using the data set from T-240 to T+963 sec from the recent telemetry downlink,

we report further analysis of BAT GRB 230328B (trigger #1162001)

(Gropp, et al., GCN Circ. 33527).  The BAT ground-calculated position is

RA, Dec = 291.037, 80.013 deg which is 

   RA(J2000)  =  19h 24m 08.8s 

   Dec(J2000) = +80d 00' 45.3" 

with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).

The partial coding was 46%.

 

The mask weighted light curve has a double peaked structure.

The light curve does not show an early afterglow as was stated in the original GCN. 

T90 (15-350 keV) is 19.23 +- 3.82 sec (estimated error including systematics).

 

The time-averaged spectrum from T-7.38 to T+25.49 sec is best fit by a power law

with an exponential cutoff.  This fit gives a photon index 1.22 +- 0.29, 

and Epeak of 99.7 +- 59.7 keV (chi squared 29.53 for 56 d.o.f.).  For this

model the total fluence in the 15-150 keV band is 4.3 +- 0.2 x 10^-06 erg/cm2

and the 1-sec peak flux measured from T+0.26 sec in the 15-150 keV band is

8.4 +- 0.5 ph/cm2/sec.  A fit to a simple power law gives a photon index

of 1.63 +- 0.07 (chi squared 35.85 for 57 d.o.f.).  All the quoted errors

are at the 90% confidence level. 

 

The results of the batgrbproduct analysis are available at

http://gcn.gsfc.nasa.gov/notices_s/1162001/BA/

 

 

 

 


GRB_name: GRB230330A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33542
SUBJECT: GRB 230330A: Fermi GBM Final Real-time Localization
DATE:    23/03/30 04:44:38 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 04:34:29 UT on 30 Mar 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230330A (trigger 701843674.478352 / 230330191).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 282.7, Dec = -12.6 (J2000 degrees, equivalent to J2000 18h 50m, -12d 35'), with a statistical uncertainty of 4.0 degrees.

The angle from the Fermi LAT boresight is 47.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230330191/quicklook/glg_skymap_all_bn230330191.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230330191/quicklook/glg_healpix_all_bn230330191.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230330191/quicklook/glg_lc_medres34_bn230330191.gif


GRB_name: GRB230328B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33543
SUBJECT: GRB 230328B: GRBAlpha detection
DATE:    23/03/30 11:54:37 GMT
FROM:    Marianna Dafcikova at Masaryk University  <500025@mail.muni.cz>

M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), N. Werner
(Masaryk U.), M. Ohno, H. Takahashi (Hiroshima U.), L. Meszaros, B. Csak
(Konkoly Observatory), N. Husarikova, F. Munz , M. Topinka, M. Kolar, J.-P.
Breuer, F. Hroch (Masaryk U.), T. Urbanec, M. Kasal,  A. Povalac (Brno U.
of Technology), J. Hudec, J. Kapus, M. Frajt (Spacemanic s.r.o), R. Laszlo,
M. Koleda (Needronix s.r.o), M. Smelko, P. Hanak, P. Lipovsky (Technical U.
of Kosice), G. Galgoczi (Wigner Research Center/Eotvos U.), Y. Uchida, H.
Poon, H. Matake (Hiroshima U.), N. Uchida (ISAS/JAXA), T. Bozoki (Eotvos
U.), G. Dalya (Eotvos U.), T. Enoto (Kyoto U.), Zs. Frei (Eotvos U.), G.
Friss (Eotvos U.), Y. Fukazawa, K. Hirose (Hiroshima U.), S. Hisadomi
(Nagoya U.), Y. Ichinohe (Rikkyo U.), K. Kapas (Eotvos U.), L. L. Kiss
(Konkoly Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.),
H. Odaka (Univ of Tokyo), J. Takatsy (Eotvos U.), K. Torigoe (Hiroshima
U.), N. Kogiso, M. Yoneyama (Osaka Metropolitan U.), M. Moritaki (U.
Tokyo), T. Kano (U. Michigan) -- the GRBAlpha collaboration.

The long-duration GRB 230328B (Fermi/GBM detection: GCN 33526; Swift/BAT
detection: GCN 33527; AstroSat/CZTI detection: GCN 33532; GECAM-B
detection: trigger no. 165) was observed by the GRBAlpha 1U CubeSat (Pal et
al. 2023; arXiv:2302.10048).


The detection was confirmed at the peak time 2023-03-28 14:54:49 UTC. The
T90 duration measured by GRBAlpha is 8 s and the overall significance
during T90 reaches 13 sigma. GRBAlpha entered the outer Van Allen radiation
belt during the tail part of the burst.


The light curve obtained by GRBAlpha is available here:
https://grbalpha.konkoly.hu/static/share/GRB230328B_GCN.pdf


All GRBAlpha detections are listed at:
https://monoceros.physics.muni.cz/hea/GRBAlpha/

GRBAlpha, launched on 2021 March 22, is a demonstration mission for a
future CubeSat constellation (Werner et al. Proc. SPIE 2018). The detector
of GRBAlpha consists of a 75 x 75 x 5 mm3 CsI scintillator read out by a
SiPM array, covering the energy range from ~50 keV to ~1000 keV. To
increase the duty cycle and the downlink rate, the upgrade of the on-board
data acquisition software stack is in progress. The ground segment is also
supported by the radio amateur community and it takes advantage of the
SatNOGS network for increased data downlink volume.


GRB_name: GRB230328B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33544
SUBJECT: Konus-Wind detection of GRB 230328B
DATE:    23/03/30 14:13:25 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, D. Frederiks, M. Ulanov, A. Tsvetkova,
A. Lysenko, A. Ridnaia, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration GRB 230328B
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 33526;
Swift-BAT detection: Gropp et al., GCN Circ. 33527;
Markwardt et al., GCN Circ. 33541;
AstroSat-CZTI detection: Waratkar et al., GCN Circ. 33532;
GRBAlpha detection: Dafcikova et al., GCN Circ. 33543;)
triggered Konus-Wind at T0=53688.873 s UT (14:54:48.873).

The burst light curve shows a multi-peaked structure
which starts at ~T0-3.3 s and has a total duration of ~12 s.
The emission is seen up to ~2 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB230328_T53688/

As observed by Konus-Wind, the burst
had a fluence of 7.12(-0.51,+0.58)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0+0.430 s,
of 2.87(-0.77,+0.78)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 5 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -1.38(-0.13,+0.14)
and Ep = 151(-21,+29) keV (chi2 = 73/75 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.2
(chi2 = 74/24 dof).

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.


GRB_name: GRB230330B
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33545
SUBJECT: GRB 230330B: Fermi GBM Final Localization
DATE:    23/03/30 16:48:56 GMT
FROM:    Joshua Wood at MSFC/Fermi-GBM  <joshua.r.wood@nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

"At 00:26:04 UT on 30 March 2023, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 230330B (trigger 701828769/230330018).

The on-ground calculated location, using the Fermi GBM trigger data,
is RA = 65.05, Dec = -35.22 (J2000 degrees, equivalent to J2000 4h 20m, -35d 13'),
with a statistical uncertainty of 8.61 degrees.

The angle from the Fermi LAT boresight is 32 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230330018/quicklook/glg_skymap_all_bn230330018.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230330018/quicklook/glg_healpix_all_bn230330018.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230330018/quicklook/glg_lc_medres34_bn230330018.gif"


GRB_name: GRB230328B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33547
SUBJECT: GRB 230328B: 3.6m DOT multiband optical observation
DATE:    23/03/31 07:49:48 GMT
FROM:    Amit Kumar Ror at ARIES  <mitturor77894@gmail.com>

Amit K. Ror, Rahul Gupta, S. B. Pandey, A. Ghosh, A. Aryan, and K. Misra
(ARIES) report:

GRB 230328B was triggered by Swift-BAT at 14:54:48 UT and Fermi-GBM at
14:54:47.43 UT on 28-03-2023 (Gropp et al. 2023 GCN 33527, Dalessi et al.
2023 GCN 33531). The prompt emission was also detected by other space-based
facilities like AstroSat-CZTI (Waratkar et al. 2023, GCN 33532), GRBAlpha
(Dafcikova et al. 2023, GCN 33543), and Konus-Wind (Svinkin et al. 2023,
GCN 33544). We searched for extended GeV emission for a temporal window of
10 ks since the GBM trigger, based on available LAT data. However, we did
not find the detection of any GeV photons, and an upper limit was obtained
for an energy flux < 5.2 x 10^{-10} erg/cm2/s in the energy range 100 MeV -
100 GeV with TS < 20.

We observed the field of GRB 230328B using the 3.6m Devasthal Optical
Telescope located at the Devasthal observatory of the Aryabhatta Research
Institute of Observational Sciences (ARIES), Nainital, India. We have taken
multiple frames with an exposure time of 300 sec each in several optical
passbands. We clearly detect the optical afterglow discovered by Swift-UVOT
in each individual image. The estimated preliminary magnitude is as follows:

Date Start_UT T_start-T0 (days) Filter  Exp time (sec)       magnitude

==============================================================

2023-03-28 21:51:54.44   ~0.29          R         300 sec  20.30 +/- 0.08

The magnitude quoted is not corrected for the galactic and host extinctions
in the direction of the burst. Photometric calibration is performed using
the standard stars from the USNO-B1 catalog.

The detection of the optical afterglow is consistent with the observation
of Gropp et al. 2023 (GCN 33527), Pankov et al. 2023 (GCN 33528), Belkin et
al. 2023 (GCN 33530), Lu et al. 2023 (GCN 33534), Catapano et al. (33535),
Suresh et al. (GCN 33536), Adami et al. (GCN 33537), Gompertz et al. (GCN
33538), Komesh et al. (GCN 33539), Lu et al. 2023 (GCN 33540)

By combining our R-band magnitude with the observations of Pankov et al.
2023 (GCN 33528) and Belkin et al. 2023 (GCN 33530), we have determined the
preliminary flux decay index of 0.55 +/-0.06.

This circular may be cited. The 3.6m Devasthal Optical Telescope (DOT) is a
recently commissioned facility in the Northern Himalayan region of India
(long: 79 41 04E, lat: 29 21 40N, alt: 2540m) owned and operated by
the Aryabhatta
Research Institute of Observational Sciences (ARIES), Nainital (
https://www.aries.res.in). The authors of this GCN circular thankfully
acknowledge the consistent support from the staff members to run and
maintain the 3.6m DOT.


GRB_name: GRB230328B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33549
SUBJECT: GRB 230328B: CAHA 2.2m/CAFOS detection
DATE:    23/03/31 19:29:32 GMT
FROM:    J. F. Agui Fernandez at IAA-CSIC  <feli@iaa.es>

J. F. Agui Fernandez (IAA-CSIC), A. de Ugarte Postigo (OCA/CNRS),
C. C. Thoene (ASU-CAS), M. Blazek (CAHA) , Ana Guijarro (CAHA)
and S. Cikota (CAHA) report:

We observed the afterglow of GR230328B (Fermi/GBM Detection: Fermi GBM
Team GCN 33526, Swift detection: Gropp et al. GCN 33527) with CAFOS
mounted on the 2.2 m telescope at the Calar Alto Observatory (Almeria, 
Spain).
The observations consisted of 5 x 360 s in Rc-band and were obtained at 
mean
epoch of 0.4717 days after the GRB. The afterglow is clearly detected with
Rc = 21.00 Â± 0.06 (AB) mag measured against comparison stars from the
PanSTARRS catalogue.


GRB_name: GRB230328B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33550
SUBJECT: GRB 230328B : GRANDMA/Kilonova-Catcher optical detection
DATE:    23/03/31 20:37:22 GMT
FROM:    Damien Turpin at NAOC (CAS)  <dturpin-astro@hotmail.com>

F. Kugel (KNC), D. Turpin (CEA), S. Karpov (FZU), T. Hussenot-Desenonges 
(IJCLab), S. Antier (OCA/Artemis), P.A. Duverne (APC, U. Paris Cit),
P. Hello (IJCLab), A. Klotz (OMP/IRAP) report on behalf of the 
GRANDMA/Kilonova-Catcher collaboration:

The Kilonova-Catcher telescope network responded to the alert of 
GRB 230328B (Swift detection: Gropp et al., GCN 33527;
Fermi GBM detection: Veres et al., GCN 33526). 

The KNC observations were taken by F. Kugel with an ARTEMIS CCD ATIK-460ex 
camera mounted in the 0.4-m f/2.8 reflector telescope in the Chante-Perdrix 
Observatory (France).
The afterglow is detected in the 36x60s unfiltered coadded images at
about 5.2 hours (midtime of the exposure) after the Swift/BAT trigger time.

Below, we report our photometric measurement in Rc magnitude.
-------------------------------------------------------------
T-T0 (day)  |Exposure| Filter | Mag +/- err |Mag.Lim. (AB)
-------------------------------------------------------------
0.22172 | 36 x 60s | Rc | 20.19 +/- 0.10 | 21.4 (3 sigma)

Our detection is consistent with the detections and limits previously reported
in Pankov et al., GCN 33528.; Belkin, GCN 33530; Lu et al., GCN 33534;
Catapano et al., GCN 33535; Suresh et al., GCN 33536.; Adami et al., 
GCN 33537; Gompertz et al., GCN 33538; Komesh et al., GCN 33539;
Lu et al., GCN 33540; Ror et al., GCN 33547; Agui Fernandez et al., GCN 33549

The GRANDMA/Kilonova-Cacther images have been calibrated using field
stars from the PanSTARRS-DR1 catalog using the STDpipe pipeline
(Karpov 2022) and the ps1/r to Rc mag conversion from (Pancino et al. 2022).

GRANDMA is a worldwide telescope network (grandma.ijclab.in2p3.fr)
devoted to the observation of transients in the context of multi-messenger
astrophysics (Antier et al. 2020 MNRAS 497, 5518). Kilonova-Catcher (KNC) is
the citizen science program of GRANDMA (http://kilonovacatcher.in2p3.fr/).


GRB_name: GRB230307A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33551
SUBJECT: GRB 230307A: Bad Time Intervals for Fermi GBM data
DATE:    23/04/01 01:57:34 GMT
FROM:    Sarah Dalessi at UAH  <sd0104@uah.edu>

S. Dalessi (UAH) reports on behalf of the Fermi GBM Team:

"The Fermi Gamma-ray Burst Monitor data for GRB 230307A has a period
of bad time intervals, affecting all data types. At particularly high
rates the TTE data has data loss due to the bandwidth limit between
the instrument and the spacecraft. CTIME and CSPEC data experience
deadtime but do not experience similar losses due to electronics
bandwidth. However, at particularly high rates both CTIME and CSPEC
are affected by pulse pile-up, which will distort the spectra (see
https://arxiv.org/abs/2303.14172). For CTIME and CSPEC, pulse pile-up
occurs for GRB pulses during the time interval of 2.5-11.0 seconds for
the BGO detector B1 and the interval 2.5-7.5 seconds for the NaI
detector Na, with T0 referenced to the GBM trigger time. The TTE
losses happen within these time intervals, with packet losses for
high-rate GRB pulses between 3 to 7 seconds. We recommend the
exclusion of these time intervals for GBM analysis of this burst, as
well as caution in using bins adjacent to these selections.


Additionally, due to the orientation of the burst, we recommend only
using BGO detector B1 and NaI detector Na for analysis of this burst.
All the other detectors either have >60deg source angles or are
blocked by the spacecraft itself."


GRB_name: GRB230402A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33553
SUBJECT: GRB 230402A: Fermi GBM Final Real-time Localization
DATE:    23/04/02 07:42:54 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 07:32:35 UT on 2 Apr 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230402A (trigger 702113560.95607 / 230402314).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 93.1, Dec = -14.6 (J2000 degrees, equivalent to J2000 06h 12m, -14d 35'), with a statistical uncertainty of 1.0 degrees.

The angle from the Fermi LAT boresight is 18.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230402314/quicklook/glg_skymap_all_bn230402314.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230402314/quicklook/glg_healpix_all_bn230402314.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230402314/quicklook/glg_lc_medres34_bn230402314.gif


GRB_name: GRB230402A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33554
SUBJECT: Fermi GRB 230402A: Global MASTER-Net observations report 
DATE:    23/04/02 16:45:20 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-Kislovodsk robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 230402A ( Fermi GBM team, GCN 33553) errorbox  32029 sec after notice time and 32063 sec after trigger time at 2023-04-02 16:26:59 UT, with upper limit up to  15.8 mag. Observations started at twilight.  The observations began at zenith distance = 61 deg. The sun  altitude  is -9.7 deg. 

The galactic latitude b = -15 deg., longitude l = 222 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2208192

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   32093 | 2023-04-02 16:26:59 |   MASTER-Kislovodsk | (06h 16m 40.71s , -13d 55m 08.5s) |   C |    60 | 15.1 |        
   32093 | 2023-04-02 16:26:59 |   MASTER-Kislovodsk | (06h 12m 36.97s , -13d 34m 24.3s) |   C |    60 | 14.9 |        
   32173 | 2023-04-02 16:28:19 |   MASTER-Kislovodsk | (06h 20m 08.03s , -15d 50m 10.7s) |   C |    60 | 15.3 |        
   32173 | 2023-04-02 16:28:19 |   MASTER-Kislovodsk | (06h 16m 01.99s , -15d 29m 26.3s) |   C |    60 | 15.1 |        
   32254 | 2023-04-02 16:29:39 |   MASTER-Kislovodsk | (06h 04m 14.25s , -15d 51m 29.2s) |   C |    60 | 15.1 |        
   32334 | 2023-04-02 16:30:59 |   MASTER-Kislovodsk | (06h 13m 51.45s , -12d 03m 02.3s) |   C |    60 | 15.4 |        
   32334 | 2023-04-02 16:30:59 |   MASTER-Kislovodsk | (06h 09m 48.34s , -11d 42m 21.4s) |   C |    60 | 15.3 |        
   32414 | 2023-04-02 16:32:19 |   MASTER-Kislovodsk | (06h 01m 04.95s , -13d 55m 45.9s) |   C |    60 | 15.4 |        
   32815 | 2023-04-02 16:39:00 |   MASTER-Kislovodsk | (06h 16m 46.40s , -13d 56m 31.5s) |   C |    60 | 15.8 |        
   32815 | 2023-04-02 16:39:01 |   MASTER-Kislovodsk | (06h 12m 42.92s , -13d 35m 50.8s) |   C |    60 | 15.7 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB230402A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33555
SUBJECT: GRB 230402A: AGILE detection
DATE:    23/04/02 19:27:16 GMT
FROM:    Claudio Casentini at INAF-IAPS  <claudio.casentini@inaf.it>

C. Casentini (INAF/IAPS), C. Pittori (SSDC, and INAF/OAR),
M. Tavani (INAF/IAPS and Uni. Roma Tor Vergata), F. Lucarelli,
F. Verrecchia(SSDC, and INAF/OAR), A. Argan, M. Cardillo, Y. Evangelista,
L. Foffano, G. Piano (INAF/IAPS), A. Addis, L. Baroncelli, A. Bulgarelli,
A. Di Piano, V. Fioretti, G.Panebianco, N. Parmiggiani (INAF/OAS-Bologna),
M. Romani (INAF/OA-Brera), M. Marisaldi (INAF/OAS-Bologna, Bergen
University),
M. Pilia, A. Trois (INAF/OA Cagliari), I. Donnarumma, E. Menegoni, A.Ursi
(ASI),
A. Giuliani (INAF/IASF-Mi) and P. Tempesta (TeleSpazio),
report on behalf of the AGILE Team:

The AGILE satellite detected the GRB 230402A at T0 = 2023-04-02 07:32:35 s
(UTC),
reported by Fermi GBM (GCN #33553).

The burst is clearly visible in the AGILE scientific ratemeters of the
MiniCALorimeter (MCAL; 0.4-100 MeV), and AntiCoincidence (AC; 50-200 keV)
detectors.
The event lasted about 6 s and it released a total number of 5504 counts in
the MCAL
detector (above a background rate of 576 Hz), and 23987 counts in AC
detector
(above a background rate of 2949 Hz). The AGILE ratemeters light curves can
be found
at http://www.agilescienceapp.it/notices/GRB230402A_AGILE_RM_ND.png .

At the T0, the event was 81 deg off-axis.

Additional analysis of AGILE data is in progress. Automatic MCAL GRB alert
Notices
can be found at: https://gcn.gsfc.nasa.gov/agile_mcal.html


GRB_name: GRB230328B
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33556
SUBJECT: GRB 230328B: Swift/UVOT Detection
DATE:    23/04/02 23:10:18 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <mhs18@psu.edu>

M. H. Siegel (PSU) and J. D. Gropp (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 230328B
114 s after the BAT trigger (Gropp et al., GCN Circ. 33527).
A source consistent with the XRT position (Osborne et al. GCN Circ. 33529) is
detected in the initial UVOT exposures, confirming the initial
optical detections (Pankov et al., GCN Circ. 33528; Catapano & Izzo, GCN Circ.
33535; Suresh et al., GCN Circ. 33536; Adami et al., GCN Circ. 33537; Komesh
et al., GCN Circ. 33539).

The preliminary UVOT position is:
    RA  (J2000) =  19:24:01.88 = 291.00783 (deg.)
    Dec (J2000) = +80:00:34.6  =  80.00962 (deg.)
with an estimated uncertainty of 0.44 arc sec. (radius, 90% confidence).

Preliminary detections and 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: 

Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white (fc)         114          264          147         18.38 +/- 0.05
White             5537         5735          196         20.16 +/- 0.14
white            28147        28879          713         21.88 +/- 0.32
v                  655          849           39        >17.6
b                  582          774           39        >18.3
u (fc)             326          576          246         19.20 +/- 0.16
w1                 705          725           19        >18.5
w2                 805          825           19        >18.0

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.070 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB230228A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33557
SUBJECT: GRB 230228A: detection by GTC of the potential host galaxy
DATE:    23/04/03 03:19:37 GMT
FROM:    Youdong HU at IAA-CSIC  <huyoudong072@hotmail.com>

Y.-D. Hu, E. Fernandez-Garcia, A. J. Castro-Tirado, I. Perez-Garcia, M.D. Caballero-Garcia, R. Sanchez-Ramirez (IAA-CSIC), Bin-bin Zhang (NJU) and D. Garcia (GTC, IAC) on behalf of a larger collaboration, report:

Following the detection of short GRB 230228A by Swift (Dichiara et al. GCN 33378), we triggered the 10.4 m Gran Telescopio de Canarias (GTC) in La Palma (Spain) to image the GRB location with the OSIRIS instrument in two epochs (Mar 1 20:16 UT and Mar 3, 20:02 UT, 1.6 and 2.6 days post-burst respectively). Within the XRT error region, a constant brightness (z-band magnitude = 23.6) is found, which we suggest as the potential host galaxy of this burst.

We thank the excellent support from the GTC staff.


GRB_name: GRB230307A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33558
SUBJECT: GRB 230307A: Chandra late-time detection of the X-ray afterglow
DATE:    23/04/03 17:31:15 GMT
FROM:    Wen-fai Fong at Northwestern U  <wfong@northwestern.edu>

A. Rouco Escorial (ESA/ESAC), B. Gompertz (U. Birmingham), W. Fong (Northwestern), A. J. Levan (Radboud), J. Rastinejad (Northwestern), E. Berger (Harvard) report:

"The Chandra X-ray Observatory observed the extremely bright long-duration GRB 230307A (Fermi GBM Team, GCN 33405; Xiong et al., GCN 33406; Dalessi et al., GCN 33407, 33411; Burns et al., GCN 33414) starting on 2023 April 1st 21:30:20 UT, with a median observation time of ~25.4 days post-trigger. We obtained an ACIS-S observation under Directors Discretionary Time (Proposal 24408902, ObsID 27778; PI: Fong), with an effective exposure time of ~16.8 ks.

At the XRT position (Evans et al. GCN 33429), we identify 4 net counts, compared to an expected background of ~0.2 counts. Using the method of Kraft, Burrows & Nousek (1991ApJ 374 444) for the confidence limits in the low counts regime this suggests the detection of a source at >3-sigma confidence. We infer a count rate of ~2.4E-4 counts/seconds. Performing a joint spectral fit with the Swift/XRT data we obtain an X-ray flux of FX ~ 1.1e-14 erg/s/cm2.

Combining this Chandra observation with earlier XRT data, we infer a power-law decline with a decay index (FX~t^alpha) of alpha~-1.3.

We thank Pat Slane, Harvey Tananbaum and the CXO staff for the rapid approval and planning of these observations."


GRB_name: GRB230328B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33559
SUBJECT: GRB 230328B: Multa observatory optical afterglow observation
DATE:    23/04/03 23:51:33 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

N. Pankov (HSE), L. Elenin (KIAM RAS), A. Krylov (KIAM RAS), A. 
Pozanenko (IKI), S. Belkin (IKI) report on behalf of GRB IKI FuN:

We observed  the field of GRB 230328B (Gropp et al. GCN 33527; Veres et 
al., GCN 33526; Dalessi et al., GCN 33531; Waratkar et al., GCN 33532; 
Dafcikova  et al., GCN 33543; Svinkin  et al. GCN  33544) with 
Santel-400 (0.4m) telescope of ISON-Multa observatory (Altay Republic) 
in  Clear filter on 2023-03-28 starting on (UT) 15:16:06. We detect the 
optical afterglow of GRB 230328B (Gropp et al. GCN 33527; Pankov et al. 
GCN 33528; Belkin et al. GCN 33530; Lu et al. GCN 33534; Catapano et al. 
GCN  33535; Suresh et al. GCN 33536; Adami  et al. GCN 33537; Gompertz 
et al. GCN 33538; Komesh  et al. GCN 33539; Lu et al. GCN 33540; Ror et 
al. GCN 33547; Kugel  et al. GCN 33550; Siegel et al. GCN 33556).

Preliminary photometry  of the afterglow source is following

Date        UT start  t-T0    Exp.  Filter   OT    Err.  UL(3sigma)
                    (mid, days) (s)

2023-03-28  15:16:06 0.04603  90*60 Clear    18.9  0.1   20.0

The photometry is based on nearby USNO-B1.0 (R2) stars.


GRB_name: GRB230402A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33562
SUBJECT: GRB 230402A: AstroSat CZTI detection
DATE:    23/04/04 14:11:20 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

P K. Navaneeth (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. 
Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao 
(IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat 
CZTI collaboration:

Analysis of AstroSat CZTI data with the ML pipeline (Abraham et al., 
2021, MNRAS, 504, 3084) and the CIFT framework (Sharma et al., 2021, 
JApA, 42, 73) showed the detection of a bright long GRB 230402A which 
was also detected by Fermi (Fermi GBM Team, GCN 33553), and AGILE 
(Casentini et al., GCN 33555).

The source was clearly detected in the 20-200 keV energy range. The 
light curve peaks at 2023-04-02 07:32:36.5 UTC. The measured peak count 
rate associated with the burst is 517 (+50, -55) counts/s above the 
background in the combined data of all quadrants, with a total of 4283 
(+374, -394) counts. The local mean background count rate was 456 (+3, 
-4) counts/s. Using cumulative rates, we measure a T90 of 37 (+3, -5) s. 
In the preliminary analysis, we find 588 Compton events associated with 
this event.

The source was also clearly detected in the CsI anticoincidence (Veto) 
detector in the 100-500 keV energy range. The light curve peaks at 
2023-04-02 07:32:36.1 UTC. The measured peak count rate associated with 
the burst is 692 (+67, -76) counts/s above the background in the 
combined data of three quadrants (out of four), with a total of 5504 
(+695, -805) counts. The local mean background count rate was 1185 (+2, 
-2) counts/s. We measure a T90 of 37 (+21, -9) s from the cumulative 
Veto light curve.

CZTI is built by a TIFR-led consortium of institutes across India, 
including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research 
Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB230402A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33563
SUBJECT: GRB 230402A: CALET Gamma-Ray Burst Monitor detection
DATE:    23/04/04 15:29:58 GMT
FROM:    Yuta Kawakubo at Louisiana State U./CALET  <kawakubo1@lsu.edu>

M. L. Cherry (LSU), A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka (ICRR), S. Torii, Y. Akaike, K. Kobayashi (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), N. Cannady (GSFC/UMBC),
S. Ricciarini (U of Florence),
P. S. Marrocchesi (U of Siena),
and the CALET collaboration:

The long GRB 230402A (Fermi GBM Final Real-time Localization: 
Fermi GBM team, GCN Circ. 33553; AGILE detection: Casentini et al.,
GCN Circ 33555; AstroSat CZTI detection: Navaneeth et al., GCN Circ. 
33562) triggered the CALET Gamma-ray Burst Monitor (CGBM)at 
07:32:38.72 UTC on 2 April 2023
(http://cgbm.calet.jp/cgbm_trigger/flight/1364455761/).
The burst signal was seen by only the SGM detector.

The burst light curve shows a single pulse that starts
at T-3.2 sec and ends at T+4.8 sec.
The T90 and T50 durations measured by the SGM data are 7.0 +/- 1.0 sec
and 4.0 +/- 1.0 sec (40-1000 keV), respectively.

The ground-processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1364455761/

The CALET data used in this analysis are provided by
the Waseda CALET Operation Center located at Waseda University.


GRB_name: GRB230404A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33564
SUBJECT: GRB 230404A: Fermi GBM Final Real-time Localization
DATE:    23/04/04 23:10:23 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 23:00:07 UT on 4 Apr 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230404A (trigger 702342012.327256 / 230404958).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 139.8, Dec = -3.5 (J2000 degrees, equivalent to J2000 09h 19m, -3d 30'), with a statistical uncertainty of 3.5 degrees.

The angle from the Fermi LAT boresight is 56.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230404958/quicklook/glg_skymap_all_bn230404958.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230404958/quicklook/glg_healpix_all_bn230404958.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230404958/quicklook/glg_lc_medres34_bn230404958.gif


GRB_name: GRB230404A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33565
SUBJECT: GRB 230404A: AstroSat CZTI detection
DATE:    23/04/05 09:28:55 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

P K. Navaneeth (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. 
Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao 
(IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat 
CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 
2021, JApA, 42, 73) showed the detection of a long GRB 230404A which was 
also detected by Fermi (Fermi GBM Team, GCN 33564).

The source was detected in the 20-200 keV energy range. The light curve 
peaks at 2023-04-04 23:00:07.5 UTC. The measured peak count rate 
associated with the burst is 75 (+30, -10) counts/s above the background 
in the combined data of two quadrants (out of four), with a total of 753 
(+275, -296) counts. The local mean background count rate was 224 (+1, 
-2) counts/s. Using cumulative rates, we measure a T90 of 29 (+10, -12) 
s.

The source was also detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range. The light curve peaks at 2023-04-04 
23:00:07.0 UTC. The measured peak count rate associated with the burst 
is 246 (+67, -54) counts/s above the background in the combined data of 
all quadrants, with a total of 3668 (+1002, -1058) counts. The local 
mean background count rate was 1491 (+6, -6) counts/s. We measure a T90 
of 48 (+7, -12) s from the cumulative Veto light curve.

While the two T90 measurements agree within error bars, the difference 
is higher than typical measurements. There are two possibilities for 
this: firstly, there may be an intrinsic energy dependence in T90, with 
it being higher at higher energies. The second is that at the instant of 
this GRB, AstroSat was relatively close to the South Atlantic Anomaly, 
which increased the background and hence the uncertainty in our T90 
measurements.

CZTI is built by a TIFR-led consortium of institutes across India, 
including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research 
Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB230405A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33566
SUBJECT: GRB 230405A: Fermi GBM Final Real-time Localization
DATE:    23/04/05 15:13:37 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 15:03:04 UT on 5 Apr 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230405A (trigger 702399789.583538 / 230405627).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 341.9, Dec = 77.0 (J2000 degrees, equivalent to J2000 22h 47m, 77d 00'), with a statistical uncertainty of 5.6 degrees.

The angle from the Fermi LAT boresight is 138.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230405627/quicklook/glg_skymap_all_bn230405627.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230405627/quicklook/glg_healpix_all_bn230405627.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230405627/quicklook/glg_lc_medres34_bn230405627.gif


GRB_name: GRB230405A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33568
SUBJECT: Fermi GRB 230405A: Global MASTER-Net observations report 
DATE:    23/04/05 15:45:19 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-Amur robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Blagoveshchensk State Pedagogical University) started inspect of the Fermi GRB 230405A ( Fermi GBM team, GCN 33566) errorbox  535 sec after notice time and 568 sec after trigger time at 2023-04-05 15:12:33 UT, with upper limit up to  14.3 mag. The observations began at zenith distance = 53 deg. The sun  altitude  is -33.8 deg. 

The galactic latitude b = 16 deg., longitude l = 116 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2208858

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

     624 | 2023-04-05 15:12:33 |         MASTER-Amur | (23h 39m 32.03s , +76d 55m 04.5s) |   C |   110 | 14.3 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB230307A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33569
SUBJECT: GRB 230307A: JWST observations consistent with the presence of a kilonova
DATE:    23/04/05 19:08:10 GMT
FROM:    Andrew Levan at U.of Leicester  <a.levan@astro.ru.nl>

A. J. Levan (Radboud), B. P. Gompertz (U. Birmingham), D. B. Malesani (Radboud/DAWN NBI), N. R. Tanvir (Leicester), E. Burns (LSU), R. Salvaterra (INAF/IASF-Mi), K. Ackley (U. Warwick), G. P. Lamb (LJMU), J. Fynbo (DAWN NBI), B. Schneider (MIT), P. Jakobsson (U. Iceland), L. Izzo (DARK/NBI), A. Fruchter (STScI), D. Watson (DAWN NBI), M. Kennedy (UCC), J. Hjorth (DARK/NBI), G. Pugliese (API UvA), K. Bhirombhakdi (STScI), V. S. Dhillon (Sheffield/IAC)  report for a larger collaboration.
 
"We obtained observations of the exceptionally bright, long-duration GRB 230307A (Fermi GBM team, GCN 33405; Xiong et al., GCN 33406; Xiao & Krucker, GCN 33410; Cosentini et al., GCN 33412; Navaneeth et al., GCN 33415) with the James Webb Space Telescope on 5 April 2023 (about 28.8 days after the GRB). Observations were obtained with NIRCam in the F070W, F115W, F150W, F277W, F356W and F444W filters.
 
At the location of the optical afterglow (Levan et al., GCN 33439) we find a faint source with F150W(AB) ~ 28.4 +/- 0.3. From our provisional analysis, the source appears point-like, without any evident extension. It is thus unlikely to be due to an underlying host galaxy. The lack of a host galaxy in observations of this depth is unusual for a long GRB, particularly for one as bright as GRB 230307A. 

In addition, observations in the redder bands show a much brighter source, with F444W(AB)~24.5 +/- 0.1, consistent with a power-law slope of approximately nu^-3 through the redder bands. 

We suggest that the very red colour and the absence of a host galaxy make a kilonova the most likely interpretation. In this case the burst may arise from a compact binary ejected from the nearby galaxy at z=0.065, which is ~40 kpc away in projection (Gillanders et al. GCN 33485).3

Further analysis is ongoing.
 
We thank the staff of STScI for their work to get these observations rapidly scheduled, in particular Katey Alatalo, Alaina Henry, Armin Rest and Wilson Skipper."


GRB_name: GRB230405B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33570
SUBJECT: GRB 230405B: Fermi GBM Final Real-time Localization
DATE:    23/04/05 20:08:29 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 19:58:03 UT on 5 Apr 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230405B (trigger 702417488.872428 / 230405832).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 276.9, Dec = -50.3 (J2000 degrees, equivalent to J2000 18h 27m, -50d 17'), with a statistical uncertainty of 1.6 degrees.

The angle from the Fermi LAT boresight is 110.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230405832/quicklook/glg_skymap_all_bn230405832.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230405832/quicklook/glg_healpix_all_bn230405832.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230405832/quicklook/glg_lc_medres34_bn230405832.gif


GRB_name: GRB230405B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33571
SUBJECT: GRB 230405B: Swift detection of a burst
DATE:    23/04/05 20:11:06 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

K. L. Page (U Leicester), C. Gronwall (PSU), J.D. Gropp (PSU),
J. A. Kennea (PSU), M. J. Moss (GWU), D. M. Palmer (LANL),
T. M. Parsotan (GSFC/UMBC/CRESSTII) and M. H. Siegel (PSU) report on
behalf of the Neil Gehrels Swift Observatory Team:

At 19:58:03 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 230405B (trigger=1163119).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 271.467, -47.070 which is 
   RA(J2000) = 18h 05m 52s
   Dec(J2000) = -47d 04' 12"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single-peaked
structure with a duration of about 10 sec.  The peak count rate
was ~16000 counts/sec (15-350 keV), at ~2 sec after the trigger. 

The XRT began observing the field at 19:59:09.2 UT, 65.7 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 271.44108, -47.06898 which
is equivalent to:
   RA(J2000)  = 18h 05m 45.86s
   Dec(J2000) = -47d 04' 08.3"
with an uncertainty of 3.5 arcseconds (radius, 90% containment). This
location is 63 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at https://www.swift.ac.uk/sper.  We
cannot determine whether the source is fading at the present time. No
spectrum from the promptly downlinked event data is yet available to
determine the column density. 

The initial flux in the 2.5 s image was 9.19e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 74 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers 100% of
the XRT error circle. The typical 3-sigma upper limit has been about 19.6 mag. 
The 8'x8' region for the list of sources generated on-board covers 100% of the
XRT error circle. No correction has been made for the expected extinction
corresponding to E(B-V) of 0.166. 

Burst Advocate for this burst is K. L. Page (kimlpage1978 AT gmail.com). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)


GRB_name: GRB230405B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33572
SUBJECT: GRB 230405B: Prompt enhanced Swift-XRT position
DATE:    23/04/05 20:37:19 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P.A. Evans (U. Leicester) reports on behalf of the Swift-XRT team:

Using  promptly downlinked XRT event data for GRB 230405B, we find an
enhanced XRT position of the afterglow: RA, Dec: 271.44100, -47.06977
which is equivalent to:
   RA (J2000)  = 18 05 45.84
   Dec (J2000) = -47 04 11.2
with an uncertainty of 1.9 arcseconds (radius, 90% confidence).
Analysis of the promptly available data is online at
http://www.swift.ac.uk/sper/1163119.

Position enhancement is is described by Goad et al. (2007, A&A, 476,
1401) and Evans et al. (2009, MNRAS, 397, 1177).

This circular is an official product of the Swift-XRT team.


GRB_name: GRB230405B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33573
SUBJECT: Swift GRB 230405B: Global MASTER-Net observations report 
DATE:    23/04/05 21:18:28 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) was pointed to the Swift GRB 230405B ( K. L. Page et al., GCN 33571) errorbox  4283 sec after notice time and 4302 sec after trigger time at 2023-04-05 21:09:46 UT, with upper limit up to  16.0 mag. The observations began at zenith distance = 73 deg. The sun  altitude  is -56.4 deg. 

The galactic latitude b = -13 deg., longitude l = 346 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2208901

We obtain a following upper limits.  

Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

    4393 |         MASTER-SAAO | P\\ |   180 | 16.0 |        
    4393 |         MASTER-SAAO |  P/ |   180 | 16.0 |        


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB230405B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33574
SUBJECT: GRB 230405B: Enhanced Swift-XRT position
DATE:    23/04/06 00:12:52 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A.P. Beardmore, P.A. Evans, M.R. Goad and J.P. Osborne (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 1065 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 230405B, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 271.44062, -47.06983 which is equivalent
to:

RA (J2000): 18h 05m 45.75s
Dec (J2000): -47d 04' 11.4"

with an uncertainty of 2.2 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB230405B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33575
SUBJECT: GRB 230405B: AstroSat CZTI detection
DATE:    23/04/06 07:26:20 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

P K. Navaneeth (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. 
Bhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao 
(IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat 
CZTI collaboration:

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 
2021, JApA, 42, 73) showed the detection of a long GRB 230405B which was 
also detected by Fermi (Fermi GBM Team, GCN 33570), and Swift (Page et 
al., GCN 33571).

The source was clearly detected in the 20-200 keV energy range. The 
light curve peaks at 2023-04-05 19:58:05.65 UTC. The measured peak count 
rate associated with the burst is 894 (+200, -92) counts/s above the 
background in the combined data of three quadrants (out of four), with a 
total of 1098 (+189, -189) counts. The local mean background count rate 
was 336 (+8, -10) counts/s. Using cumulative rates, we measure a T90 of 
4.3 (+1.0, -1.7) s.

The source was also clearly detected in the CsI anticoincidence (Veto) 
detector in the 100-500 keV energy range. The light curve peaks at 
2023-04-05 19:58:05.12 UTC. The measured peak count rate associated with 
the burst is 1564 (+88, -98) counts/s above the background in the 
combined data of all quadrants, with a total of 3078 (+369, -404) 
counts. The local mean background count rate was 1466 (+5, -6) counts/s. 
We measure a T90 of 4.1 (+5.1, -1.5) s from the cumulative Veto light 
curve.

CZTI is built by a TIFR-led consortium of institutes across India, 
including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research 
Organisation funded, managed, and facilitated the project.

CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb


GRB_name: GRB230405B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33576
SUBJECT: GRB 230405B: Swift/UVOT Upper Limits 
DATE:    23/04/06 08:06:53 GMT
FROM:    Samantha Oates at MSSL  <samantha.oates@alumni.ucl.ac.uk>

S. R. Oates (U. Birmingham) and K. L. Page (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 230405B
75 s after the BAT trigger (Page et al., GCN Circ. 33571).
No optical afterglow consistent with the XRT position
(Beardmore et al. GCN Circ. 33574)
is detected in the initial UVOT exposures.
Preliminary 3-sigma upper limits using the UVOT photometric system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the first
finding chart (FC) exposure and subsequent exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)         Mag

white_FC            75          224          147         >20.5
u_FC               287          537          246         >19.7
white               75         1363          373         >20.7
v                  618         4860          274         >19.1
b                  542         1339           78         >19.0
u                  287         1313          304         >19.7
w1                 668         1289           78         >18.5
m2                 642         5065          274         >19.4
w2                 593         1389           97         >18.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.166 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB230307A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33577
SUBJECT: GRB 230307A: short mininum variability timescale compatible with a merger origin
DATE:    23/04/06 11:06:22 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

A.E. Camisasca, C. Guidorzi, M. Bulla (Ferrara U.), L. Amati, A. Rossi 
(INAF-OAS), G. Stratta, P. Singh (Goethe U. Frankfurt) on behalf of a 
larger collaboration report:

"We determined the minimum variability timescale (MVT) of GRB230307A 
(Fermi GBM team, GCN 33405; Xiong et al., GCN 33406; Xiao & Krucker, GCN 
33410; Cosentini et al., GCN 33412; Navaneeth et al., GCN 33415) from 
the Fermi/GBM light curve (NaI detectors 10 and 6) following the 
prescriptions of Camisasca et al. (2023), i.e. as the minimum full width 
half maximum (FWHM_min) of all statistically significant pulses, and 
found FWHM_min = 28 (-7, +10) ms. Combined with the T90=34.56 +- 0.6 s 
(Fermi GBM team, GCN 33405), in the T90-FWHM_min plot GRB230307A (purple 
star in the Figure below) lies in the region populated by other 
long-lasting merger candidates, such as also GRB191019A (green star in 
Figure; Levan et al. 2023; Lazzati et al. 2023). In particular, it lies 
very close to the merger GRB211211A (Gompertz et al. 2023; Mei et al. 
2022; Rastinejad et al. 2022; Troja et al 2022; Yang et al 2022).
Despite its long duration and complex light curve, its short MVT 
therefore supports the merger origin for GRB230307A, as suggested by the 
possible evidence for kilonova emission reported by Levan et al. (GCN 
33569).
In addition, assuming a redshift z=0.065 (Gillanders et al. GCN 33485), 
a fluence of 3.6e-3 erg cm-2 (Svinkin et al. GCN 33427) would correspond 
to Eiso=3.7e52 erg. Combined with Ep~1 MeV (Svinkin et al.), the 
position of GRB230307A in the Ep-Eiso plane seems to be more compatible 
with short rather than long GRBs.

http://www.fe.infn.it/u/guidorzi/T90_vs_FWHMmin_neu.pdf   (Figure 
adapted from Camisasca et al. 2023)

References
- Camisasca et al., 2023, A&A, 671, A112, 
https://doi.org/10.1051/0004-6361/202245657
- Gompertz et al., 2023, Nature Astronomy, 7, 67
- Lazzati et al., 2023, arXiv:2303.12935
- Levan et al., 2023, arXiv:2303.12912
- Mei et al., 2022, Nature, 612, 236
- Rastinejad et al., 2022, Nature, 612, 223
- Troja et al., 2022, Nature, 612, 228
- Yang et al., 2022, Nature, 612, 232


GRB_name: GRB230307A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33578
SUBJECT: GRB 230307A: good match with kilonova models
DATE:    23/04/06 14:41:22 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

M. Bulla, A.E. Camisasca, C. Guidorzi (Ferrara U.), L. Amati, A. Rossi 
(INAF-OAS), G. Stratta, P. Singh (Goethe U. Frankfurt) on behalf of a 
larger collaboration report: We compared kilonova models computed with 
the latest version of the radiative transfer code POSSIS (Bulla 2023, 
MNRAS, 520, 2558) to photometric data of a faint source associated with 
GRB 230307A as reported by Levan et al. (GCN 33569). Assuming a redshift 
z=0.065 (Gillanders et al. GCN 33485) and a Galactic extinction of 
E(B-V)=0.0743 mag (Schlafly & Finkbeiner 2011, ApJ, 737, 103), we find a 
reasonably good match to observations in both the F150W and F444W 
filters for a model viewed along the jet axis (face-on) and with two 
ejecta components: 1) a dynamical ejecta component with a mass of 0.005 
Msun, an average velocity of 0.25c and an average electron fraction 
Ye=0.15; 2) and a disk-wind ejecta component with a mass of 0.05 Msun, 
an average velocity of 0.1c and an average electron fraction Ye=0.3 (see 
figure at the link below). This supports the claim of kilonova emission 
by Levan et al. (GCN 33569) and strengthens the interpretation of GRB 
230307A as a merger event, as also suggested by the properties of the 
gamma-ray prompt emission (Camisasca et al. GCN 33577). Further analysis 
is ongoing. Figure: 
https://drive.google.com/file/d/1XhpfwCXQxWWS_G7WQ1fUSZKSiZXnwXiJ/view?usp=sharing


GRB_name: GRB230307A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33579
SUBJECT: GRB 230307A: further analysis of the Konus-Wind detection and rest-frame energetics
DATE:    23/04/06 16:11:37 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, D. Frederiks, A. Ridnaia, A. Tsvetkova,
and A. Lysenko on behalf of the Konus-Wind team, report:

Following the probable host galaxy identification
(Gillanders et al. GCN Circ. 33485; Levan at al., GCN Circ. 33569),
we present a further analysis of the KW detection
(Svinkin et al., GCN Circ. 33427)
of the extremely bright, long-duration GRB 230307A
(GCNs 33405, 33406, 33407, 33410, 33411, 33412,
33413, 33414, 33415, 33416, 33418, 33424, 33425, 33461).

As measured by KW the burst durations are
T50=9.17+/-0.04 s and T90 = 31.2 +/-0.4 s,
both in the 100-1700 keV energy band.
The refined burst fluence is 4.05(-0.03,+0.03)x10^-3 erg/cm2,
and a 64-ms peak flux, measured from T0+6.224 s,
is 6.85(-0.27,+0.27)x10^-4 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

Assuming the redshift of the host galaxy z=0.065 (GCN 33485)
and a standard cosmology model with H_0 = 67.3 km/s/Mpc,
Omega_M = 0.315, and Omega_Lambda = 0.685 (Planck Collaboration, 2014),
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is (4.21+/-0.03)x10^52 erg,
the peak luminosity L_iso is (7.58 +/-0.33)x10^51 erg/s,
the rest-frame peak energy of the time-integrated spectrum,
Ep,i,z is (933+/-12) keV, and the rest-frame peak energy at the peak 
luminosity Ep,p,z is (1388+/-52) keV.

With these values, GRB 230307A is outside the 90% prediction band of
both 'Amati' and 'Yonetoku' relations built for the sample of >300 long
KW GRBs with known redshifts (Tsvetkova et al., 2017; Tsvetkova et al., 
2021).
In both Eiso-Ep,i,z and Liso-Ep,p,z planes, GRB 230307A is shifted 
towards the short-hard (Type I, merger-origin) GRB population,
see http://www.ioffe.ru/LEA/GRBs/GRB230307_T56645/GRB230307A_rest_frame.pdf

The analysis of KW data is ongoing and its results will be reported 
elsewhere.


GRB_name: GRB230307A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33580
SUBJECT: GRB 230307A: JWST NIRSpec observations, possible higher redshift
DATE:    23/04/06 17:00:47 GMT
FROM:    Andrew Levan at U.of Leicester  <a.levan@astro.ru.nl>

A.J. Levan (Radboud), D. Watson (DAWN/NBI), J. Hjorth (DARK/NBI), N. R. Tanvir (Leicester), D. B. Malesani (Radboud, DAWN/NBI), E. Burns (LSU), B. P. Schneider (MIT), J. P. U. Fynbo (DAWN/NBI), S. D. Vergani (CNRS-Paris Observatory), W. Fong (Northwestern), A. Fruchter (STScI), G. Pugliese (API/UvA), S. Smartt (Oxford) report for a larger collaboration:

â€œIn addition to the JWST/NIRCam observations of GRB 230307A (Fermi GBM team, GCN 33405) reported in GCN 33569, we also obtained observations with NIRSpec on 5 April 2023. The observations were obtained for a total integration time of approximately 1 hour, using the prism to obtain a spectrum in the range 0.5-5.5 um. The trace confirms the spectral shape measured from NIRCam observations. Blueward of 2 um, the source has a flat spectrum, but low signal to noise, and a strong upturn redward of 2 um. 

We note the presence of two weak, narrow emission features in the spectrum, both of which are offset from the trace by approximately 0.1-0.2". These are consistent with the H-alpha and [O III] (5007 AA) emission lines at z = 3.87. Excess flux in the spectrum is also visible at the location of H-beta at this redshift. If the GRB is from a low redshift merger, as suggested by GCN 33569, then this could only be explained by a chance alignment with an unrelated background galaxy. It is hard to quantify this possibility, given that we could be seeing both transient and galaxy light, however the chances are clearly low.

Alternatively, the lines could be from the host galaxy, implying that GRB 230307A lies at z = 3.87. The very red colours of the continuum source would not naturally match the expectations of any afterglow models at z = 3.87, but in fact could be consistent with those of a dusty, red galaxy. Given only one epoch in the mid-IR is available, we cannot rule out this possibility, although such a galaxy would be extremely compact, and the transient would have to decay very steeply since the last ground-based observations. We note that, at this redshift, GRB 230307A would be by far the most energetic burst ever detected, with E_iso ~ 10^56 erg. This would be an order of magnitude more energetic than any of the ~500 GRBs with available isotropic energy releases. This may require a unique progenitor system.â€


GRB_name: GRB230405B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33582
SUBJECT: GRB 230405B: MeerLICHT upper limits
DATE:    23/04/06 19:05:47 GMT
FROM:    Simon de Wet at UCT  <dwtsim002@myuct.ac.za>

S. de Wet (UCT), P.J. Groot (Radboud/UCT/SAAO), P.M. Vreeswijk (Radboud),
D. Pieterse (Radboud) and D.B. Malesani (Radboud and DAWN/NBI) report on
behalf of the MeerLICHT consortium:

Following the detection of GRB 230405B by Swift/BAT along with its X-ray
counterpart (Page et al., GCN 33571), the 0.6 m wide-field MeerLICHT
optical telescope located at Sutherland, South Africa, obtained a repeated
series of 60-s exposures in the q,u,g,r,i,z bands following the sequence
quqgqrqiqz. Observations began 6.38 hours after the Swift trigger at 2023
April 6 02:20:05 UT and continued for a further 1.82 hours.

Our individual 60-s exposures show no new optical source consistent with
the enhanced XRT position (Beardmore et al., GCN 33574) when compared to
archival DECam images of this field. We therefore co-added the images in
each filter in order to obtain deeper limits. We report the following
3-sigma AB magnitude limits at the XRT position at ~7.2 hours post-trigger:

u > 20.5
g > 21.3
q > 22.6
r > 21.2
i > 21.1
z > 20.1

MeerLICHT is built and run by a consortium consisting of Radboud
University, University of Cape Town, the South African Astronomical
Observatory, the University of Oxford, the University of Manchester and the
University of Amsterdam.


GRB_name: GRB230405B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33583
SUBJECT: GRB 230405B: Fermi GBM Observation
DATE:    23/04/06 21:06:17 GMT
FROM:    Joshua Wood at MSFC/Fermi-GBM  <joshua.r.wood@nasa.gov>

J. Wood (NASA/MSFC) and C. Meegan (UAH) report on behalf of
the Fermi Gamma-ray Burst Monitor Team:

"At 19:58:03 UT on 05 April 2023, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 230405B (trigger 702417488/230405832).
which was also detected by the Swift/BAT and Swift/XRT (K. L. Page et al. 2023, GCN 33571).
The Fermi GBM on-ground location is consistent with the Swift XRT position.

The angle from the Fermi LAT boresight is 105 degrees.

The GBM light curve consists of a single pulse with a duration (T90)
of about 4.3 s (50-300 keV). The time-averaged spectrum
from T0+0.0 to T0+5.1 s is best fit by
a Band function with Epeak = 225 +/- 11 keV,
alpha = -0.53 +/- 0.05, and beta = -2.4 +/- 0.1.

The event fluence (10-1000 keV) in this time interval is
(1.2 +/- 0.2)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.5 s in the 10-1000 keV band is 27.5 +/- 0.5 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog:
https://heasarc.gsfc.nasa.gov/W3Browse/fermi/fermigbrst.html

For Fermi GBM data and info, please visit the official Fermi GBM Support Page:
https://fermi.gsfc.nasa.gov/ssc/data/access/gbm/"


GRB_name: GRB230405B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33584
SUBJECT: GRB 230405B: Swift-XRT refined Analysis
DATE:    23/04/07 02:01:14 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P.A. Evans (U. Leicester), T. Sbarrato (INAF-OAB), P. D'Avanzo
(INAF-OAB), M.G. Bernardini (INAF-OAB), A. Tohuvavohu (U. Toronto),
D.N. Burrows (PSU), J. D. Gropp (PSU), J.P. Osborne (U. Leicester) and
K.L. Page report on behalf of the Swift-XRT team:

We have analysed 6.5 ks of XRT data for GRB 230405B (Page et al. GCN
Circ. 33571), from 54 s to 75.0 ks after the  BAT trigger. The data
comprise 246 s in Windowed Timing (WT) mode (the first 10 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. The enhanced XRT position for this burst was given by Beardmore
et al. (GCN Circ. 33572).

The light curve can be modelled with an initial power-law decay with an
index of alpha=0.88 (+/-0.04), followed by a break at T+937 s to an
alpha of 1.14 (+0.16, -0.05).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.10 (+0.12, -0.11). The
best-fitting absorption column is  4.0 (+0.6, -0.5) x 10^21 cm^-2, in
excess of the Galactic value of 1.6 x 10^21 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.95 (+0.17, -0.16)
and a best-fitting absorption column of 5.4 (+1.1, -1.0) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 4.2 x 10^-11 (6.8 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      5.4 (+1.1, -1.0) x 10^21 cm^-2
Galactic foreground: 1.6 x 10^21 cm^-2
Excess significance: 6.2 sigma
Photon index:      1.95 (+0.17, -0.16)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01163119.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB230405B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33585
SUBJECT: GRB 230405B: AGILE detection
DATE:    23/04/07 08:42:42 GMT
FROM:    Claudio Casentini at INAF-IAPS  <claudio.casentini@inaf.it>

C. Casentini, M. Cardillo (INAF/IAPS), C. Pittori (SSDC, and INAF/OAR),
M. Tavani (INAF/IAPS and Uni. Roma Tor Vergata), F. Lucarelli,
F. Verrecchia(SSDC, and INAF/OAR), A. Argan, Y. Evangelista, L. Foffano,
G. Piano (INAF/IAPS), A. Addis, L. Baroncelli, A. Bulgarelli, A. Di Piano,
V. Fioretti, G.Panebianco, N. Parmiggiani (INAF/OAS-Bologna),
M. Romani (INAF/OA-Brera), M. Marisaldi (INAF/OAS-Bologna, Bergen
University),
M. Pilia, A. Trois (INAF/OA Cagliari), I. Donnarumma, E. Menegoni, A.Ursi
(ASI),
A. Giuliani (INAF/IASF-Mi) and P. Tempesta (TeleSpazio),
report on behalf of the AGILE Team:

The AGILE satellite detected the GRB 230405B at T0 = 2023-04-05 19:58:03 s
(UTC),
reported by Fermi (GCNs #33570, #33583), Swift (GCNs #33571, #33572,
#33574, #33576,
#33584), AstroSat CZTI (GCN #33575), MeerLICHT (GCN #33582), and Global
MASTER-Net
(GCN #33573).

The burst is clearly visible in the AGILE scientific ratemeters of the
MiniCALorimeter (MCAL; 0.4-100 MeV), and AntiCoincidence (AC; 50-200 keV)
detectors.
The event lasted about 5 s and it released a total number of 3105 counts in
the MCAL
detector (above a background rate of 539 Hz), and 16691 counts in AC-Top
detector
(above a background rate of 2650 Hz). The AGILE ratemeters light curves can
be found
at http://www.agilescienceapp.it/notices/GRB230405B_AGILE_RM_ND.png .

At the T0, the event was 83 deg off-axis.

Additional analysis of AGILE data is in progress. Automatic MCAL GRB alert
Notices
can be found at: https://gcn.gsfc.nasa.gov/agile_mcal.html

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GRB_name: GRB230405B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33586
SUBJECT: Konus-Wind detection of GRB 230405B
DATE:    23/04/07 11:34:01 GMT
FROM:    Anna Ridnaia at Ioffe Institute  <ridnaia@mail.ioffe.ru>

A.Ridnaia, D. Frederiks, A.Lysenko, D. Svinkin,
A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The long-duration GRB 230405B
(Fermi-GBM detection: The Fermi GBM team, GCN 33570;
Wood & Meegan, GCN 33583;
Swift-BAT detection: Page et al., GCN 33571;
AstroSat CZTI detection: Navaneeth et al., GCN 33575;
AGILE detection: Casentini et al., GCN 33585)
triggered Konus-Wind at T0=71884.77 s UT (19:58:04.770).

The burst light curve shows a single pulse,
which starts at ~T0-6.1 s and has a total duration of ~10.7 s.
The emission is seen up to ~2 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB230405_T71884/

As observed by Konus-Wind, the burst
had a fluence of 2.24(-0.23,+0.27)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+1.088 s,
of 9.76(-1.97,+2.26)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

The time-averaged spectrum of the burst
(measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 10 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.37(-0.26,+0.30),
the high energy photon index beta = -2.75(-0.64,+0.31),
the peak energy Ep = 184(-20,+23) keV
(chi2 = 101/91 dof).

All the quoted errors are at the 90% confidence level.
All the quoted values are preliminary.


GRB_name: GRB230405B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33590
SUBJECT: GRB 230405B: VZLUSAT-2 detection
DATE:    23/04/07 21:07:07 GMT
FROM:    Marianna Dafcikova at Masaryk University  <500025@mail.muni.cz>

M. Dafcikova, J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory),  N.
Werner  (Masaryk U.), M. Ohno (Hiroshima U.),  L. Meszaros, B. Csak
(Konkoly Observatory), H. Takahashi (Hiroshima U.), F. Munz , M. Topinka,
F. Hroch, N. Husarikova, J.-P. Breuer (Masaryk U.), J. Hudec, J. Kapus, M.
Frajt, M. Rezenov (Spacemanic s.r.o), R. Laszlo (Needronix), G. Galgoczi
(Wigner Research Center/Eotvos U.), N. Uchida (ISAS/JAXA), T. Enoto (Kyoto
U.), Zs. Frei (Eotvos U.), Y. Fukazawa, K. Hirose, H. Matake (Hiroshima
U.), S. Hisadomi (Nagoya U.), Y. Ichinohe (Rikkyo U.), L. L. Kiss (Konkoly
Observatory),  T. Mizuno (Hiroshima U.), K. Nakazawa (Nagoya U.), H. Odaka
(Univ of Tokyo), K. Torigoe (Hiroshima U.), P. Svoboda, V. Daniel, J.
Dudas, M. Junas, J. Gromes (VZLU), I. Vertat (FEL ZCU)  -- the
VZLUSAT-2/GRB payload collaboration.

The long duration GRB 230405B (Fermi/GBM detection: GCN 33570; Swift/BAT
detection: GCN 33571; AstroSat detection: GCN 33575; AGILE detection: GCN
33585; Konus/Wind detection: GCN 33586; INTEGRAL/SPI-ACS detection at
2023-04-05 19:58:04) was detected by the GRB detector on board of the
VZLUSAT-2 3U CubeSat (https://www.vzlusat2.cz/en/).

The data acquisition was performed by the GRB detector unit no. 1 and the
detection was confirmed at the peak time 2023-04-05 19:58:04 UTC. The T90
duration was measured to be 3 s with the light curve resolution of 1 s. The
significance during T90 reaches 25 sigma.

The light curve obtained by VZLUSAT-2 is available here:

https://vzlusat2.konkoly.hu/static/share/GRB230405B_GCN_VZLUSAT2.pdf

All VZLUSAT-2 detections are listed at:
https://monoceros.physics.muni.cz/hea/VZLUSAT-2/

The GRB detectors on VZLUSAT-2 are a demonstration payload for a future
CubeSat constellation (Werner et al. Proc. SPIE 2018). Two GRB modules of
VZLUSAT-2 are placed in a perpendicular manner and each consists of a 75 x
75 x 5 mm3 CsI scintillator read out by a SiPM array, covering the energy
range from ~30 keV to ~1000 keV. VZLUSAT-2 was launched on 2022 January 13
from Cape Canaveral.


GRB_name: GRB230409A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33591
SUBJECT: GRB 230409A: Fermi GBM Final Real-time Localization
DATE:    23/04/09 00:58:47 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 00:48:13 UT on 9 Apr 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230409A (trigger 702694098.828404 / 230409033).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 328.4, Dec = 25.1 (J2000 degrees, equivalent to J2000 21h 53m, 25d 06'), with a statistical uncertainty of 4.0 degrees.

The angle from the Fermi LAT boresight is 77.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230409033/quicklook/glg_skymap_all_bn230409033.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230409033/quicklook/glg_healpix_all_bn230409033.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230409033/quicklook/glg_lc_medres34_bn230409033.gif


GRB_name: GRB230409B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33592
SUBJECT: GRB 230409B: Swift detection of a burst
DATE:    23/04/09 05:21:45 GMT
FROM:    Kim Page at U.of Leicester  <kimlpage1978@gmail.com>

A. P. Beardmore (U Leicester), C. Gronwall (PSU),
A. Y. Lien (U Tampa), K. L. Page (U Leicester), T. Sakamoto (AGU),
M. H. Siegel (PSU) and M. A. Williams (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 04:56:57 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 230409B (trigger=1163401). Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 329.530, +52.854 which is 
   RA(J2000) = 21h 58m 07s
   Dec(J2000) = +52d 51' 15"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The immediately available BAT light curve
starts at ~ a few seconds after the BAT trigger time. The light 
curve shows a small hump from ~50 to 100 s, however, further ground 
data will be required to determine whether the hump is due to 
background fluctuation. 

The XRT began observing the field at 04:58:38.0 UT, 101.2 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 329.51486, 52.83228
which is equivalent to:
   RA(J2000)  = 21h 58m 03.57s
   Dec(J2000) = +52d 49' 56.2"
with an uncertainty of 1.9 arcseconds (radius, 90% containment). This
location is 84 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at https://www.swift.ac.uk/sper. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 7.56
x 10^21 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 386 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. The 2.7'x2.7' sub-image covers none of
the XRT error circle. The 8'x8' region for the list of sources generated
on-board covers 100% of the XRT error circle. No correction has been made for
the large, but uncertain, extinction expected. 

Burst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/)


GRB_name: GRB230409B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33594
SUBJECT: GRB 230409B: Enhanced Swift-XRT position
DATE:    23/04/09 11:34:35 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P.A. Evans, M.R. Goad, J.P. Osborne and A.P. Beardmore (U. Leicester) 
report on behalf of the Swift-XRT team.

Using 1709 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 230409B, we find an astrometrically corrected X-ray
position (using the XRT-UVOT alignment and matching UVOT field sources
to the USNO-B1 catalogue): RA, Dec = 329.51474, +52.83212 which is equivalent
to:

RA (J2000): 21h 58m 3.54s
Dec (J2000): +52d 49' 55.6"

with an uncertainty of 2.2 arcsec (radius, 90% confidence).

This position may be improved as more data are received. The latest
position can be viewed at http://www.swift.ac.uk/xrt_positions. Position
enhancement is described by Goad et al. (2007, A&A, 476, 1401) and Evans
et al. (2009, MNRAS, 397, 1177).

This circular was automatically generated, and is an official product of the
Swift-XRT team.


GRB_name: GRB230409B
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33595
SUBJECT: GRB 230409B: Swift/UVOT Detection
DATE:    23/04/09 14:26:27 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

GRB 230409B: Swift/UVOT Detection

N. Paul Kuin (UCL/MSSL) and A. P. Beardmore (U. Leicester) report
on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of
GRB 230409B  386 s after the BAT trigger (Beardmore et al.,
GCN Circ. 33592).  A weak fading source consistent with the
XRT position (Beardmore et al. GCN Circ. 33592) is detected
in the initial UVOT exposures at position RA=329.5158,
Dec=52.8321 deg.

Preliminary detections and 3-sigma upper limits using the
UVOT photometric system (Breeveld et al. 2011, AIP Conf.
Proc. 1358, 373) for the early exposures are:

Filter         T_start(s)   T_stop(s)      Exp(s)           Mag

white              386          536          147         19.35 +/- 0.20
v                  542         1931          156        >18.1
b                  642         2029          156        >19.4
u                  616         2004          156        >19.0
w1                 592         1980          156        >18.8
m2                 567         1955          156        >19.2
w2                 692         1906          136        >20.0

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 1.226 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB230409B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33596
SUBJECT: Swift GRB 230409B: Global MASTER-Net observations report 
DATE:    23/04/09 16:58:40 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-Kislovodsk robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) was pointed to the Swift GRB 230409B ( A. P. Beardmore et al., GCN 33592) errorbox  42781 sec after notice time and 42806 sec after trigger time at 2023-04-09 16:50:23 UT, with upper limit up to  15.5 mag. Observations started at twilight.  The observations began at zenith distance = 83 deg. The sun  altitude  is -12.2 deg. 

The galactic latitude b = -2 deg., longitude l = 99 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2209455

We obtain a following upper limits.  

Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   42897 |   MASTER-Kislovodsk |   C |   180 | 15.5 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB230409B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33598
SUBJECT: GRB 230409B: Swift-BAT refined analysis
DATE:    23/04/09 17:50:01 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),
C. B. Markwardt (GSFC), T. Parsotan (GSFC/UMBC),
T. Sakamoto (AGU), M. Stamatikos (OSU)
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+962 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 230409B (trigger #1163401)
(Beardmore et al., GCN Circ. 33592).  The BAT ground-calculated position
is RA, Dec = 329.516, 52.832 deg which is
   RA(J2000)  =  21h 58m 03.8s
   Dec(J2000) = +52d 49' 55.1"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 32%.

The mask-weighted light curve shows a single-pulse structure
that starts at ~T-1 s, peaks at ~T+1 s, and ends at ~T+12 s.
The hump at ~50 s to 100 s mentioned in the previous circular
(Beardmore et al., GCN Circ. 33592) is due to background fluctuation
and is not part of the burst. T90 (15-350 keV) is 9.79 +- 2.59 sec
(estimated error including systematics).

The time-averaged spectrum from T-0.58 to T+11.78 sec is best fit by a
simple
power-law model.  The power law index of the time-averaged spectrum is
1.86 +- 0.19.  The fluence in the 15-150 keV band is 9.9 +- 1.2 x 10^-7
erg/cm2.
The 1-sec peak photon flux measured from T+0.43 sec in the 15-150 keV band
is 3.7 +- 0.5 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/1163401/BA/


GRB_name: GRB230409B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33599
SUBJECT: GRB 230409B: Swift-XRT refined Analysis
DATE:    23/04/09 21:57:51 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E. Ambrosi 
(INAF-IASFPA) , D.N. Burrows (PSU), J. D. Gropp (PSU), S. Dichiara
(PSU), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester) and A.P.
Beardmore report on behalf of the Swift-XRT team:

We have analysed 6.6 ks of XRT data for GRB 230409B (Beardmore et al.
GCN Circ. 33592), from 338 s to 52.1 ks after the  BAT trigger. The
data comprise 19 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Evans et al. (GCN Circ. 33594).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.87 (+0.04, -0.03).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.97 (+0.22, -0.21). The
best-fitting absorption column is  1.23 (+0.27, -0.24) x 10^22 cm^-2,
in excess of the Galactic value of 7.6 x 10^21 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 5.2 x 10^-11 (9.9 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.23 (+0.27, -0.24) x 10^22 cm^-2
Galactic foreground: 7.6 x 10^21 cm^-2
Excess significance: 3.3 sigma
Photon index:      1.97 (+0.22, -0.21)

If the light curve continues to decay with a power-law decay index of
0.87, the count rate at T+24 hours will be 0.020 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.1 x
10^-12 (2.0 x 10^-12) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01163401.

This circular is an official product of the Swift-XRT team.


GRB_name: GRB230409C
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33600
SUBJECT: GRB 230409C: Fermi GBM Final Real-time Localization
DATE:    23/04/09 22:38:23 GMT
FROM:    Fermi GBM Team at MSFC/Fermi-GBM  <do_not_reply@GIOC.nsstc.nasa.gov>

The Fermi GBM team reports the detection of a likely LONG GRB

At 22:27:45 UT on 9 Apr 2023, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 230409C (trigger 702772070.370746 / 230409936).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 195.9, Dec = -53.4 (J2000 degrees, equivalent to J2000 13h 03m, -53d 23'), with a statistical uncertainty of 10.5 degrees.

The angle from the Fermi LAT boresight is 86.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230409936/quicklook/glg_skymap_all_bn230409936.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230409936/quicklook/glg_healpix_all_bn230409936.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2023/bn230409936/quicklook/glg_lc_medres34_bn230409936.gif


GRB_name: GRB230409A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33601
SUBJECT: Fermi GRB 230409A: Global MASTER-Net observations report 
DATE:    23/04/09 23:30:18 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-Kislovodsk robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Russia (Lomonosov MSU, Kislovodsk Solar Station of Pulkovo observatory) started inspect of the Fermi GRB 230409A ( Fermi GBM team, GCN 33591) errorbox  78316 sec after notice time and 78350 sec after trigger time at 2023-04-09 22:34:04 UT, with upper limit up to  16.4 mag. The observations began at zenith distance = 81 deg. The sun  altitude  is -36.1 deg. 

The galactic latitude b = -23 deg., longitude l = 80 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2209420

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

   78381 | 2023-04-09 22:34:04 |   MASTER-Kislovodsk | (21h 32m 27.85s , +27d 25m 20.5s) |   C |    60 | 15.8 |        
   80688 | 2023-04-09 23:12:31 |   MASTER-Kislovodsk | (22h 01m 31.30s , +25d 32m 16.4s) |   C |    60 | 15.9 |        
   80778 | 2023-04-09 23:14:01 |   MASTER-Kislovodsk | (21h 44m 39.09s , +25d 34m 00.1s) |   C |    60 | 16.2 |        
   80867 | 2023-04-09 23:15:30 |   MASTER-Kislovodsk | (21h 49m 39.80s , +27d 26m 52.0s) |   C |    60 | 15.9 |        
   81377 | 2023-04-09 23:24:00 |   MASTER-Kislovodsk | (21h 32m 28.84s , +27d 28m 26.5s) |   C |    60 | 16.4 |        
   81467 | 2023-04-09 23:25:30 |   MASTER-Kislovodsk | (21h 57m 57.31s , +23d 37m 58.9s) |   C |    60 | 14.4 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


GRB_name: GRB230409C
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  33602
SUBJECT: Fermi GRB 230409C: Global MASTER-Net observations report 
DATE:    23/04/09 23:30:34 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, V.Kornilov, E.Gorbovskoy, K.Zhirkov, N.Tyurina, P.Balanutsa, A.Kuznetsov, D. Vlasenko, 
G.Antipov, D.Zimnukhov, V.Senik, E.Minkina, A.Chasovnikov, V.Topolev, D.Kuvshinov,  D.Cheryasov, Ya.Kechin
(Lomonosov Moscow State University, SAI, Physics Department),

R. Podesta, C.Lopez, F. Podesta, C.Francile 
(Observatorio Astronomico Felix Aguilar OAFA),

R. Rebolo, M. Serra 
(The Instituto de Astrofisica de Canarias),

D. Buckley 
(South African Astronomical Observatory),

O.A. Gres, N.M. Budnev
(Irkutsk State University, API),

L.Carrasco, J.R.Valdes, V.Chavushyan, V.M.Patino Alvarez, J.Martinez, A.R.Corella, L.H.Rodriguez 
(INAOE, Guillermo Haro Astrophysics Observatory),

A. Tlatov, D. Dormidontov 
(Kislovodsk Solar Station of the Pulkovo Observatory),

A. Gabovich, V.Yurkov 
(Blagoveschensk Educational State University)


MASTER-SAAO robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in South Africa (South African Astronomical Observatory) started inspect of the Fermi GRB 230409C ( Fermi GBM team, GCN 33600) errorbox  730 sec after notice time and 764 sec after trigger time at 2023-04-09 22:40:30 UT, with upper limit up to  18.5 mag. The observations began at zenith distance = 20 deg. The sun  altitude  is -65.6 deg. 

The galactic latitude b =  9 deg., longitude l = 305 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=2209581

We obtain a following upper limits.  

Tmid-T0  |      Date Time      |          Site       |             Coord (J2000)          |Filt.| Expt. | Limit| Comment
_________|_____________________|_____________________|____________________________________|_____|_______|_______|________

     795 | 2023-04-09 22:40:30 |         MASTER-SAAO | (13h 00m 51.38s , -51d 57m 13.0s) |   C |    60 | 18.5 |        
     795 | 2023-04-09 22:40:30 |         MASTER-SAAO | (13h 02m 19.20s , -51d 57m 32.2s) |   C |    60 | 18.1 |        
     874 | 2023-04-09 22:41:49 |         MASTER-SAAO | (13h 13m 56.04s , -51d 57m 33.2s) |   C |    60 | 18.5 |        
     874 | 2023-04-09 22:41:49 |         MASTER-SAAO | (13h 15m 24.08s , -51d 57m 53.0s) |   C |    60 | 18.2 |        
     965 | 2023-04-09 22:43:20 |         MASTER-SAAO | (12h 46m 05.45s , -53d 51m 04.3s) |   C |    60 | 18.1 |        
     965 | 2023-04-09 22:43:20 |         MASTER-SAAO | (12h 44m 33.80s , -53d 50m 45.9s) |   C |    60 | 18.4 |        
    1055 | 2023-04-09 22:44:50 |         MASTER-SAAO | (12h 58m 02.95s , -53d 49m 21.9s) |   C |    60 | 18.3 |        
    1055 | 2023-04-09 22:44:50 |         MASTER-SAAO | (12h 59m 34.54s , -53d 49m 40.0s) |   C |    60 | 18.0 |        
    1135 | 2023-04-09 22:46:10 |         MASTER-SAAO | (12h 36m 21.97s , -51d 54m 36.6s) |   C |    60 | 18.5 |        
    1135 | 2023-04-09 22:46:10 |         MASTER-SAAO | (12h 37m 49.51s , -51d 54m 53.1s) |   C |    60 | 18.1 |        
    1225 | 2023-04-09 22:47:40 |         MASTER-SAAO | (12h 49m 21.46s , -51d 55m 58.1s) |   C |    60 | 18.5 |        
    1225 | 2023-04-09 22:47:40 |         MASTER-SAAO | (12h 50m 49.05s , -51d 56m 14.7s) |   C |    60 | 18.0 |        
    1305 | 2023-04-09 22:49:00 |         MASTER-SAAO | (12h 53m 17.46s , -50d 02m 47.1s) |   C |    60 | 18.5 |        
    1305 | 2023-04-09 22:49:00 |         MASTER-SAAO | (12h 54m 41.67s , -50d 03m 03.6s) |   C |    60 | 18.1 |        
    1608 | 2023-04-09 22:54:03 |         MASTER-SAAO | (13h 05m 37.80s , -50d 02m 55.9s) |   C |    60 | 18.5 |        
    1608 | 2023-04-09 22:54:03 |         MASTER-SAAO | (13h 07m 02.06s , -50d 03m 17.0s) |   C |    60 | 18.1 |        
    1698 | 2023-04-09 22:55:33 |         MASTER-SAAO | (12h 54m 22.04s , -55d 43m 47.0s) |   C |    60 | 18.3 |        
Filter C is a clear (unfiltred) band. 


The observation and reduction will continue. 
The message may be cited.


