# GCN_circulars

GRB_name: GRB220403C
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31877
SUBJECT: IPN triangulation of GRB 220403C
DATE:    22/04/11 21:09:21 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, and C. Wilson-Hodge
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 behalf of the GRS-Odyssey GRB team, report:

The bright, long-duration GRB 220403C
(Swift/BAT-GUANO detection: Tohuvavohu et al. GCN Circ. 31824)
was detected by Konus-Wind, Fermi (GBM in the trigger 670673407), INTEGRAL 
(SPI-ACS), BepiColombo (MGNS), Mars-Odyssey (HEND),
Swift (BAT), CALET (CGBM), and ISS (ASIM)
at about 36830 s UT (10:13:50).
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:
    17.570 (01h 10m 17s) -56.225 (-56d 13' 31")
  Corners:
    17.411 (01h 09m 39s) -56.347 (-56d 20' 48")
    17.548 (01h 10m 12s) -56.349 (-56d 20' 56")
    17.728 (01h 10m 55s) -56.104 (-56d 06' 13")
    17.591 (01h 10m 22s) -56.101 (-56d 06' 05")
  ---------------------------------------------
The error box area is 68 sq. arcmin, and its maximum
dimension is 18 arcmin (the minimum one is 4.3 arcmin).
The Sun distance was 62 deg.

This box may be improved.

The box is inconsistent with the GRB 220403A Konus-GBM annulus centered at
RA(2000)=355.082 deg (23h 40m 20s) Dec(2000)=-4.166 deg (-4d 09' 56"),
whose radius is 23.380 +/- 23.380 deg (3 sigma).
Thus GRB 220403C and GRB 220403A (GCN 31818) are unrelated.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB220403_T36829/IPN/

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


GRB_name: GRB220408B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31878
SUBJECT: IPN triangulation of GRB 220408B
DATE:    22/04/11 21:15:27 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 team,

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, and C. Wilson-Hodge
on behalf of the Fermi GBM team, report:

The bright, long-duration GRB 220408B
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 31854;
AstroSat-CZTI detection: Gopalakrishnan et al., GCN Circ. 31863)
was detected by Fermi (GBM trigger 671095689), Konus-Wind,
BepiColombo (MGNS), and AstroSat (CZTI) at about 26884 s UT (07:28:04).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
    92.538 (06h 10m 09s) -49.610 (-49d 36' 36")
  Corners:
    93.180 (06h 12m 43s) -49.644 (-49d 38' 40")
    93.133 (06h 12m 32s) -47.629 (-47d 37' 43")
    91.896 (06h 07m 35s) -49.572 (-49d 34' 20")
    91.889 (06h 07m 33s) -51.597 (-51d 35' 50")
  ---------------------------------------------
The error box area is 1.7 sq. deg, and its maximum
dimension is 4.0 deg (the minimum one is 48 arcmin).
The Sun distance was 86 deg.

This box may be improved.

The IPN localization is consistent with, but reduces the area of, the
Fermi GBM final position (GCN 31854).

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB220408_T26885/IPN/

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


GRB_name: GRB220411A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31879
SUBJECT: GRB 220411A: AstroSat CZTI detection
DATE:    22/04/12 04:22:16 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

R. Gopalakrishnan (IUCAA), V. Prasad (IUCAA), G. Waratkar (IITB), A. 
Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (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 detection of a long GRB 220411A which was 
also detected by Fermi - GBM (Trigger No. 220411306, GCN  31871) with 
BALROG localisation reported (Kunzweiler et al., GCN 31872).

The source was clearly detected in the 20-200 keV energy range in three 
quadrants (out of four). Two quadrants were noisy and we exclude them in 
further analysis. The light curve peaked at 2022-04-11 07:20:02.25 UT. 
The measured peak count rate associated with the burst is 337 (+151, 
-22) counts/s above the background in the combined data of two 
quadrants, with a total of 1155 (+298, -200) counts. The local mean 
background count rate was 254 (+4, -5) counts/s. Using cumulative rates, 
we measure a T90 of  19 (+1, -2) s.

It was also clearly detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range. The light curve showed a single peak of 
emission at 2022-04-11 07:20:01.00 UT. The measured peak count rate is 
499 (+73, -77) counts/s above the background in the combined Veto data 
of four quadrants, with a total of 2897 (+734, -604) counts. The local 
mean background count rate was 1722 (+3, -5) counts/s. We measure a T90 
of 26 (+13, -10) 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 [1]. CZTI is built by a TIFR-led 
consortium of institutes across India, including VSSC, ISAC, 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: GRB220412A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31881
SUBJECT: GRB 220412A: Swift detection of a burst
DATE:    22/04/12 06:53:12 GMT
FROM:    Noel Klingler at NASA-GSFC / UMBC  <njk5441@psu.edu>

N. J. Klingler (GSFC/UMBC/CRESSTII), J.D. Gropp (PSU),
K. L. Page (U Leicester), D. M. Palmer (LANL),
T. M. Parsotan (GSFC/UMBC/CRESSTII), B. Sbarufatti (PSU) and
A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 06:36:50 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 220412A (trigger=1102281).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 123.968, +30.322 which is 
   RA(J2000) = 08h 15m 52s
   Dec(J2000) = +30d 19' 19"
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 20 sec.  The peak count rate
was ~900 counts/sec (15-350 keV), at ~1 sec after the trigger. 

The XRT began observing the field at 06:38:52.9 UT, 122.7 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 123.96470, 30.34319 which is equivalent
to:
   RA(J2000)  = 08h 15m 51.53s
   Dec(J2000) = +30d 20' 35.5"
with an uncertainty of 4.5 arcseconds (radius, 90% containment). This
location is 76 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. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 126 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
0.037. 

Burst Advocate for this burst is N. J. Klingler (noelklin AT umbc.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: GRB220412A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31882
SUBJECT: GRB 220412A: RATIR Afterglow Candidate 
DATE:    22/04/12 07:25:10 GMT
FROM:    Alan M Watson at UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Eleonora Troja (UTV), Nat Butler (ASU), Alexander
Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox
(STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Enrico Ramirez-Ruiz
(UCSC), JesÃºs GonzÃ¡lez (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Harvey Moseley
(GSFC), Rosa L. Becerra (UNAM), Simone Dichiara (PSU), and OcÃ©lotl LÃ³pez (UNAM)
report:

We observed the field of GRB 220412A (Klingler et al. GCN 31881) with the
Reionization and Transients Infrared Camera (RATIR) on the 1.5m Harold Johnson
Telescope at the Observatorio AstronÃ³mico Nacional on Sierra San Pedro MÃ¡rtir
from 2022/04 12.28 to 2022/04 12.29 UTC (0.1 to 0.5 hours after the BAT
trigger), obtaining a total of 0.21 hours exposure in the r and i bands and 0.08
hours exposure in the Z, Y, J, and H bands.

We detect a bright, uncataloged source at RA = 123.967275 and declination =
30.342693 degrees (J2000), about 5.5 arcsec to the east of the current Swift XRT
SPER position. In comparison with the SDSS DR9 and 2MASS catalogs, we obtain the
following magnitudes:

   r = 19.41 +/- 0.12
   i = 19.26 +/- 0.10
   Y = 19.11 +/- 0.23

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.

Despite being slightly outside the current XRT error region, we suggest that
this source is likely to be the afterglow. Observations are continuing.

We thank the staff of the Observatorio AstronÃ³mico Nacional in San Pedro MÃ¡rtir.


GRB_name: GRB220403B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31883
SUBJECT: GRB 220403B: GRANDMA observations
DATE:    22/04/12 08:21:29 GMT
FROM:    Sarah Antier at OCA  <sarah.antier@oca.eu>

X. Song, J. Zhu (BJP), I. Tosta e Melo (INFN-LNS), J.-G. Ducoin (IAP),
N. Guessoum (AUS), W. Corradi (LNA), T. Culino (OCA), E. Gurbanov (ShAO),
E. Hesenov (ShAO), A. de Ugarte Postigo, S. Antier (OCA/Artemis), L. Wang,
A. Iskandar (XAO), X. F. Wang (TSU/BJP), X. Zeng (CTGU), D. Marchais (KNC),
P.A. Duverne, N. Leroy (IJCLAB), D. A. Kann (HETH/IAA-CSIC), A. Simon,
A. Baransky (Kyiv univ), V. Godunova (IC ICAMER),
report on behalf of GRANDMA collaboration:

The GRANDMA telescope network responded to the alert of GRB 220403B
(Klingler et al., GCN 31820). The first observations started 8 min after
the BAT trigger time.

We clearly detect the afterglow within the first hour.
We also report our 3-sigma upper limits. Magnitudes are given in the
AB system.

T-T0 (hr)| MJD   | Obser.   |Exposure| Filter | Mag +/- err  | Upp.Lim. (AB)
___________________________________________________________________________
0.13 |59672.86832| ALi-50   | 5x20s  | Clear  | 18.4 +/- 0.1 | -
0.35 |59672.8775 | ALi-50   | 20x20s | SDSS g'| 19.7 +/- 0.1 | -
0.48 |59672.88298| ALi-50   | 20x20s | SDSS r'| 18.6 +/- 0.1 | -
17.67|59673.59939| SNOVA    | 15x300s| Clear  |       -      | 19.4
24.72|59673.89285| KNC-T-CAT| 240x32s| Blue   |       -      | 20.9
24.72|59673.89285| KNC-T-CAT| 240x32s| Green  |       -      | 20.9
24.72|59673.89285| KNC-T-CAT| 240x32s| Red    |       -      | 19.9

These detections and limits are consistent with the detections and limits
previously reported in Klingler et al. (GCN 31820), Jelinek et al.
(GCN 31821),Nicuesa Guelbenzu et al. (GCN 31822), Zhu et al. (GCN 31823),
Lipunov et al. (GCN 31825),  Rossi et al. (GCN, 31826), Grossan et al.
(GCN 31830), Pankov et al. (GCN 31837, 31844), Hu et al. (GCN 31841),
and Kumar et al. (GCN 31869).

The photometry of Ali-50 was performed using field stars from the
PanSTARRs-DR1 catalog for images with SDSS g' and r' filters, and from the
Gaia gmag catalog for images with no filters. The SNOVA and T-CAT data have
been processed using field stars from the PanSTARRS-DR1 catalog and with 
the
MUPHOTEN pipeline (Duverne et al. 2021).

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: GRB220408A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31884
SUBJECT: GRB 220408A: GRANDMA observations
DATE:    22/04/12 15:20:13 GMT
FROM:    Sarah Antier at OCA  <sarah.antier@oca.eu>

S. Beradze (AbAO), U. Bhardwaj (GRAPPA), T. Culino (ESILV), P. Hello
(IJCLAB), M. Masek (FZU), G. Raaijmakers (GRAPPA), Y. Rajabov (UBAI),
T. Sadibekova (AIM/CEA-UPS), F. Z. Guo (THU), X. F. Wang (THU/BJP), Y.
Zhu (NAOC), J. Zhang (NAOC), D. A. Kann (HETH/IAA-CSIC), K. Noysena
(TRT-SRO), C. Rinner (OUCA), Z. Benkhaldoun (OUCA), J. Zhu (BJP),
X. Song (BJP), S. Antier (OCA/Artemis), P. A. Duverne (IJCLAB), A. Simon
(Kyiv Univ), A. Baransky (Kyiv Univ) and V. Godunova (IC ICAMER)
report on behalf of GRANDMA collaboration:

The GRANDMA telescope network responded to the alert of GRB 220408A
(Caputo et al. GCNC 31848). The first observations started 0.63 h after
the SWIFT BAT trigger time.

We did not detect the optical afterglow within the first 24 h.
Upper limits are given in the AB system, at 3-sigma.


T-T0(hr)| MJD    | Observatory  | Exposure| Filter | Upp. Lim. (AB)
___________________________________________________________________________
0.63 |59677.26659|KNC-T19       |9*300 s  |  V        |   17.7
1.82 |59677.31602|SRO           |7*60 s   |  R        |   19.8
6.27 |59677.50176|Xinglong-2.16m|9*400 s  |  Rc       |   20.3
8.45 |59677.59259|BJP/ALi-50    |21*20 s  |  Clear |   21.4
14.89|59677.86076|MOSS          |45*60 s  |  Clear |   20.3
18.76|59678.02215|KNC-HAO       |23*180 s |  Lumen |   20.6

These upper limits are consistent with previous reports of detections by
UVOT (Caputo et al. GCNC 31848, Oates et al. GCNC 31855), KAIT (Zheng et al.
GCNC 31850), LCO (R. Strausbaugh et al. GCNC 31862), NOT (Zhu et al. GCNC
31864), RATIR (Watson et al. GCNC 31870), and LDT (B. O'Connor et al. GCNC
31875), and the upper limits provided by MASTER (Lipunov et al. GCNC 31849),
Xinglong-2.16m (Jiang et al. GCNC 31853), GIT (Kumar et al. GCNC 31857),
LOAO/SAO/DOAO (Paek et al. GCNC 31867), and 1.3m DFOT (Kumar et al. GCNC
31868).

The SRO, Xinglong-2.16m, and Ali-50 data have been calibrated with four 
stars
from the Pan-STARRS catalog, using the transformations by Lupton (2005) and
using Rc values for the Clear Al-50 observation. The MOSSm KNC-T19 and
KNC-HAO images have been calibrated using field stars from the 
PanSTARRS-DR1
catalog, measured with the MUPHOTEN pipeline (Duverne et al. 2021).

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: GRB220412A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31885
SUBJECT: GRB 220412A: Swift/UVOT Upper Limits
DATE:    22/04/12 16:20:20 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>

A. Breeveld (UCL-MSSL) and N. Klingler (GSFC/UMBC/CRESSTII) report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 220412A 127 s after the BAT trigger 
(Klingler et al., GCN Circ. 31881).
No optical afterglow consistent with the RATIR position (Watson et al., GCN Circ. 31882) 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) exposures and subsequent exposures are:

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

white_FC           127          276          147         >20.5
u_FC               285          479          191         >19.6
white              566          758           34         >19.7
b                  542          734           34         >18.97
v                  616         1059           53         >18.18
uvw1               665          857           34         >18.25
uvw2               592         1039           58         >18.64
uvm2               813          833           20         >17.37


The magnitudes in the table are not corrected for the Galactic extinction due to the reddening of 
E(B-V) = 0.0373 in the direction of the burst (Schlegel et al. 1998).


GRB_name: GRB220412B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31886
SUBJECT: GRB 220412B: Swift detection of a short burst
DATE:    22/04/12 17:26:32 GMT
FROM:    Jeffrey Gropp at PSU  <jdg44@psu.edu>

J.D. Gropp (PSU), S. Dichiara (PSU), J. A. Kennea (PSU),
N. J. Klingler (GSFC/UMBC/CRESSTII), F. E. Marshall (NASA/GSFC),
K. L. Page (U Leicester), T. M. Parsotan (GSFC/UMBC/CRESSTII),
B. Sbarufatti (PSU) and M. H. Siegel (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 17:06:49 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 220412B (trigger=1102329).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 320.794, -0.223 which is 
   RA(J2000) = 21h 23m 11s
   Dec(J2000) = -00d 13' 23"
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 0.5 sec.  The peak count rate
was ~6000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 17:08:13.7 UT, 85.0 seconds after
the BAT trigger. No source was detected in the 2.5-s promptly available
image. We are waiting for the full dataset to detect and localise the
XRT counterpart. 

UVOT took a finding chart exposure of 130 seconds with the White filter
starting 89 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 25% of
the BAT 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
BAT 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
0.060. 

Shortly after the BAT trigger, Swift entered the South Atlantic Anomaly which 
limited data collection for the first orbit. We are awaiting further observations. 

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: GRB220412A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31887
SUBJECT: GRB 220412A: Enhanced Swift-XRT position
DATE:    22/04/12 18:40:00 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 1814 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 220412A, 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 = 123.96809, +30.34259 which is equivalent
to:

RA (J2000): 08h 15m 52.34s
Dec (J2000): +30d 20' 33.3"

with an uncertainty of 3.7 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: GRB220412A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31888
SUBJECT: GRB 220412A: Swift-XRT refined Analysis
DATE:    22/04/13 03:20:26 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. D'Ai (INAF-IASFPA), J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto),
B. Sbarufatti (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U.
Leicester), J.P. Osborne (U. Leicester), A. Melandri (INAF-OAB), T.
Sbarrato (INAF-OAB) and N.J. Klingler report on behalf of the Swift-XRT
team:

We have analysed 8.6 ks of XRT data for GRB 220412A (Klingler et al.
GCN Circ. 31881), from 106 s to 68.7 ks after the  BAT trigger. The
data comprise 158 s in Windowed Timing (WT) mode (the first 9 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 Evans
et al. (GCN Circ. 31887).

The light curve can be modelled with an initial power-law decay with an
index of alpha=2.10 (+0.08, -0.07), followed by a break at T+4017 s to
an alpha of 0.0 (+0.0, -1.1).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.02 (+0.18, -0.09). The
best-fitting absorption column is  consistent with the Galactic value
of 3.7 x 10^20 cm^-2 (Willingale et al. 2013). The PC mode spectrum has
a photon index of 1.68 (+0.22, -0.18) and a best-fitting absorption
column of 5.7 (+5.9, -2.0) x 10^20 cm^-2. The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum  is 3.9 x 10^-11 (4.3 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      5.7 (+5.9, -2.0) x 10^20 cm^-2
Galactic foreground: 3.7 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.68 (+0.22, -0.18)

If the light curve continues to decay with a power-law decay index of
0.0, the count rate at T+24 hours will be 0.011 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.4 x
10^-13 (4.7 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/01102281.

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


GRB_name: GRB220412B
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31889
SUBJECT: GRB 220412B: MITSuME Akeno optical upper limits
DATE:    22/04/13 05:34:06 GMT
FROM:    Katsuhiro L. Murata at Nagoya U  <murata@u.phys.nagoya-u.ac.jp>

K. L. Murata, M. Niwano, Y. Imai, N. Ito, Y. Takamatsu, S. Sato, R.
Hosokawa, M. Sasada, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf
of the MITSuME collaboration:

We observed the field of GRB 220412B (Gropp et al. GCN Circular #31886)
with the optical three color (g', Rc, and Ic) CCD cameras attached to the
MITSuME 50 cm telescope Akeno. The observation with a series of 60 sec
exposures started at 2022-04-12 18:28:16 UT (82 minutes after the Swift/BAT
trigger). We stacked the images with good conditions. We did not detect any
uncatalogued sources within the BAT error region (Gropp et al. GCN Circular
#31886). We obtained the 5-sigma limits of the stacked images as follows.

T0+[min] MID-UT T-EXP[sec] 5-sigma limits
------------------------------------------------------------------------------------------------
82 2022-04-12 18:55:21 2820 g'>17.9, Rc>19.0, Ic>18.5
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used the PS1 catalog for flux calibration. The magnitudes are expressed
in the AB system. The images were processed in real-time through the
MITSuME GPU reduction pipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 1,
Pages 4-24; https://github.com/MNiwano/Eclaire).


GRB_name: GRB220412A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31890
SUBJECT: Correction to GCN 31888: GRB 220412A: Swift-XRT refined Analysis
DATE:    22/04/13 05:34:52 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

K.L. Page (U. Leicester) reports on behalf of the Swift-XRT team:

In GCN 31888, the fit to the XRT light curve was stated incorrectly. There
correct details are as follows:

The light curve can be modelled with an initial power-law decay with an
index of alpha=2.10 (+0.08, -0.07), followed by a break at T+1330 s to
an alpha of 0.98 (+0.13, -0.28).

If the light curve continues to decay with a power-law decay index of
0.98, the count rate at T+24 hours will be 1.9e-03 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.4 x 10^-14
(8.1 x 10^-14) erg cm^-2 s^-1.

The remaining details in GCN 31888 were correct. We apologise for any
inconveniece.

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


GRB_name: GRB220412A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31891
SUBJECT: GRB 220412A: MITSuME Akeno optical upper limits
DATE:    22/04/13 05:35:44 GMT
FROM:    Katsuhiro L. Murata at Nagoya U  <murata@u.phys.nagoya-u.ac.jp>

K. L. Murata, M. Niwano, Y. Imai, N. Ito, Y. Takamatsu, S. Sato, R.
Hosokawa, M. Sasada, Y. Yatsu, and N. Kawai (Tokyo Tech) report on behalf
of the MITSuME collaboration:

We observed the field of GRB 220412A (Klingler et al. GCN Circular #31881,
Watson et al. GCN Circular #31882, Breeveld and Klingler et al. GCN
Circular #31885, Evans et al. GCN Circular #31887, D'Ai et al. GCN Circular
#31888) with the optical three color (g', Rc, and Ic) CCD cameras attached
to the MITSuME 50 cm telescope Akeno. The observation with a series of 60
sec exposures started at 2022-04-12 10:10:00 UT (214 minutes after the
Swift/BAT trigger). We stacked the images with good conditions. We did not
detect any uncatalogued sources within the enhanced XRT error region (Evans
et al. GCN Circular #31887). We obtained the 5-sigma limits of the stacked
images as follows.

T0+[min] MID-UT T-EXP[sec] 5-sigma limits
------------------------------------------------------------------------------------------------
214 2022-04-12 10:53:37 3960 g'>19.0, Rc>19.3, Ic>18.8
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used the PS1 catalog for flux calibration. The magnitudes are expressed
in the AB system. The images were processed in real-time through the
MITSuME GPU reduction pipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 1,
Pages 4-24; https://github.com/MNiwano/Eclaire).


GRB_name: GRB220412B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31892
SUBJECT: GRB 220412B: GIT optical upper limit
DATE:    22/04/13 08:47:40 GMT
FROM:    Harsh Kumar at Indian Inst of Tech,Bombay  <harshkosli13@gmail.com>

H. Kumar (IITB), V. Swain (IITB), R. Norbu (IAO), G. C. Anupama (IIA), V.
Bhalerao (IITB), S. Barway (IIA) report on behalf of the GIT team:

We observed the short GRB 220412B detected by Swift-BAT (J.D. Gropp et al.,
GCN #31886) with the 0.7m *GROWTH-India Telescope* (GIT). We obtained multiple
300-sec exposures in the r' filter. We did not detect any new source in our
stacked image within the BAT uncertainty region of 3 arcmin circle, around
R.A.= 320.794, DEC.= -0.223. The obtained upper limit follows as:

-------------------------------------------------------------------------

 JD (mid) | T_mid-T0(hrs) | Exposure (sec) | Filter | Lim_mag (5-sigma) |

-------------------------------------------------------------------------

2459682.452891 | 5.75 | 300 x 6 (stacked) | r' | > 20.25 |

-------------------------------------------------------------------------

Our upper limit is consistent with results from K. L. Murata et al. (GCN
#31889). The magnitudes are calibrated against Pan-STARRS DR1 (Chambers et
al., 2016) and not corrected for Galactic extinction.

The GROWTH India Telescope (GIT) 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: GRB220408A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31893
SUBJECT: GRB 220408A: HCT optical upper limit
DATE:    22/04/13 08:52:20 GMT
FROM:    Harsh Kumar at Indian Inst of Tech,Bombay  <harshkosli13@gmail.com>

H. Kumar (IITB), V. Swain (IITB), R. Norbu (IAO), G. C. Anupama (IIA), S.
Barway (IIA), V. Bhalerao (IITB), A. Dutta (IIA), R. Gupta (ARIES), K.
Misra (ARIES), D. Panchal (ARIES), S.B. Pandey (ARIES), D.K. Sahu (IIA)
report on behalf of the HCT team:


We observed GRB 220408A detected by the Fermi-GBM (GCN # 31847), Swift-BAT
(R. Caputo et al., GCN #31848) and optical afterglow discovered by Swift-UVOT
(GCN #31848) with the 2.0m Himalayan Chandra Telescope (HCT) of the Indian
Astronomical Observatory (IAO). We obtained multiple exposures in the Rc
and Ic filters. We did not detect any new source in our stacked image at
the afterglow location.

The obtained upper limit follows as:

-------------------------------------------------------------------------

 JD (mid) | T_mid-T0(hrs) | Exposure (sec) | Filter | Lim_mag (5-sigma) |

-------------------------------------------------------------------------

 2459678.203981 | 11.13 | 300 x 3 (stacked) | Rc | > 22.51 |

 2459678.225509 | 11.64 | 300 x 3 (stacked) | Ic | > 22.46 |

-------------------------------------------------------------------------

Our upper limits are consistent with results from R. Caputo et al. (GCN
#31848), W. Zheng and A.V. Filippenko (GCN #31850), S.Q. Jiang et al. (GCN
#3185), S.R. Oates & R. Caputo (GCN #31855), H. Kumar et al. (GCN #31857),
Y.-D. Hu et al. (GCN #31859), R. Strausbaugh et al. (GCN #31862), Z. Zhu et
al. (GCN #31864), G.S.H. Paek et al. (GCN #31867), A. Kumar et al. (GCN
#31868), A.M. Watson et al. (GCN #31870), B. O'Connor et al. (GCN #31875),
S. Beradze et al. (GCN #31884).

The magnitudes are in the AB system of magnitude, calibrated against
PanSTARRS (Flewelling et al., 2018) using Lupton's transformation equations
available at
http://classic.sdss.org/dr4/algorithms/sdssUBVRITransform.html#Lupton2005.
The magnitudes are not corrected for galactic extinction.


These observations were carried out under the ToO program HCT-2022-C1-P14
(PI: Harsh Kumar). We thank the HCT staff for their support during the
observations. The Indian Astronomical Observatory is operated by the Indian
Institute of Astrophysics, Bengaluru, India.


GRB_name: GRB220412B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31894
SUBJECT: Swift GRB 220412B: Global MASTER-Net observations report 
DATE:    22/04/13 10:16:30 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-OAGH robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) was pointed to the Swift GRB 220412B ( J.D. Gropp et al., GCN 31886) errorbox  61446 sec after notice time and 61475 sec after trigger time at 2022-04-13 10:11:24 UT, with upper limit up to  17.5 mag. The observations began at zenith distance = 77 deg. The sun  altitude  is -32.6 deg. 

The galactic latitude b = -34 deg., longitude l = 53 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1940975

We obtain a following upper limits.  

Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   61505 |         MASTER-OAGH |   C |    60 | 17.5 |        
   61505 |         MASTER-OAGH |   C |    60 | 17.3 |        
Filter C is a clear (unfiltred) band. 


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


GRB_name: GRB220406A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31895
SUBJECT: IPN triangulation of short/soft GRB 220406A
DATE:    22/04/13 11:25:59 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 HEND/Mars-Odyssey team,

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

A short-duration, soft GRB 220406A
was detected by Konus-Wind, INTEGRAL (SPI-ACS),
Mars-Odyssey (HEND), and Swift (BAT) at about 1661 s UT (00:27:41).
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:
  324.994 (21h 39m 59s) +64.925 (+64d 55' 31")
 Corners:
  330.496 (22h 01m 59s) +64.859 (+64d 51' 31")
  319.682 (21h 18m 44s) +64.833 (+64d 49' 59")
  319.519 (21h 18m 04s) +64.773 (+64d 46' 21")
  330.308 (22h 01m 14s) +64.812 (+64d 48' 43")
 ---------------------------------------------
The error box area is 882 sq. arcmin, and its maximum
dimension is 4.7 deg (the minimum one is 3 arcmin).
The Sun distance was 66 deg.

This box may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220406_T01660/IPN

The time history and spectrum will be given in forthcoming GCN Circulars.


GRB_name: GRB220408B
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31896
SUBJECT: GRB 220408B: Fermi-LAT detection
DATE:    22/04/13 15:49:24 GMT
FROM:    Elisabetta Bissaldi at INFN,Bari  <elisabetta.bissaldi@ba.infn.it>

E. Bissaldi (Politecnico and INFN Bari), M. Arimoto (Kanazawa Univ.),
S. Ciprini (INFN and ASI), F. Giacchino (INFN Roma Tor Vergata and ASI),
M. Giroletti (INAF/IRA Bologna), and L. Scotton (CNRS/IN2P3/LUPM)
report on behalf of the Fermi-LAT team:


"On April 8, 2022, Fermi-LAT detected high-energy emission from GRB 220408B,
which was also detected by Fermi-GBM (trigger 671095689 / 220408311, GCN 31854),
AstroSat CZTI (Gopalakrishnan et al. 2022, GCN 31863) and was reported by the IPN
(Kozyrev et al. 2022. GCN 31878).

The best LAT on-ground location is found to be

RA, Dec = 92.48, -50.97 (degrees, J2000)

with an error radius of 0.06 deg (90 % containment, statistical error only).
This was 30 deg from the LAT boresight at the time of the GBM trigger:

T0 = 07:28:04.65 UT.

The data from the Fermi-LAT show a significant increase in the event rate
that is spatially and temporally correlated with the GBM emission
with high significance.
The photon flux above 100 MeV in the time interval 0-2500s
after the GBM trigger is (2.0 +/- 0.5)E-06 ph/cm2/s.

The estimated photon index above 100 MeV is -1.9 +/- 0.2.

The highest-energy photon is a 22 GeV event
which is observed 42 seconds after the GBM trigger.


The Fermi-LAT point of contact for this burst is
Elisabetta Bissaldi (elisabetta.bissaldi@ba.infn.it).


The Fermi-LAT is a pair conversion telescope designed to cover the energy band
from 20 MeV to greater than 300 GeV. It is the product of an international
collaboration between NASA and DOE in the U.S. and many scientific institutions
across France, Italy, Japan and Sweden."


GRB_name: GRB220412B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31897
SUBJECT: GRB 220412B: Swift-XRT observations
DATE:    22/04/13 18:27:35 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

V. D'Elia (SSDC & INAF-OAR), A. D'Ai (INAF-IASFPA), J. D. Gropp (PSU),
J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), K.L. Page (U.
Leicester), A.P. Beardmore (U. Leicester), A. Melandri (INAF-OAB) and
J.D. Gropp (PSU) report on behalf of the Swift-XRT team:

We have analysed 7.8 ks of Photon Counting (PC) mode XRT data for the
Swift-BAT-detected burst GRB 220412B (Gropp et al. GCN Circ. 31886),
collected between T0+4.7 ks and T0+29.1 ks. 

No X-ray sources have been detected consistent with being within 296
arcsec of the Swift-BAT position. The 3-sigma upper limit in the field
is 0.001 ct  s^-1, corresponding to a 0.3-10 keV observed flux of
4.2e-14 erg cm^-2 s^-1 (assuming a typical GRB spectrum).

Four uncatalogued sources were 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/01102329.

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


GRB_name: GRB220412A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31898
SUBJECT: GRB 220412A: RATIR Observations of the Fading Afterglow 
DATE:    22/04/13 20:05:34 GMT
FROM:    Alan M Watson at UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Eleonora Troja (UTV), Alexander
Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox
(STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Enrico Ramirez-Ruiz
(UCSC), JesÃºs GonzÃ¡lez (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Harvey Moseley
(GSFC), Rosa L. Becerra (UNAM), Simone Dichiara (PSU), and OcÃ©lotl LÃ³pez (UNAM)
report:

We observed the field of GRB 220412A (Klingler et al. GCN 31881) with the
Reionization and Transients Infrared Camera (RATIR) on the 1.5m Harold Johnson
Telescope at the Observatorio AstronÃ³mico Nacional on Sierra San Pedro MÃ¡rtir
from 2022-04-12 06:39 to 06:56 UTC (0.04 to 0.33 hours after the trigger) and
2022-04-13 03:16 to 04:38 UTC (20.65 to 22.00 hours after the trigger) obtaining
totals of 0.21 and 1.07 hours of exposure in the i band.

In comparison with the SDSS DR9 catalog, the afterglow candidate reported by
Watson et al. (GCN Circ. 31882) has faded from i = 19.27 +/- 0.10 to i = 20.64
+/- 0.08. This photometry for the first night supersedes the preliminary
photometry reported by Watson et al. 

We note that the optical light curve does not seem to show the same steep
decline as the XRT light curve reported by the UKSSDC. From 0.33 to 21 hours,
the XRT light curve falls by a factor of about 50, whereas our photometry only
falls by a factor of about 3.5.

We have checked the SDSS DR9 i image, and there is no apparent host galaxy
present at the position of the afterglow bright enough to explain the
apparent slow decline.

Further observations are planned.

We thank the staff of the Observatorio AstronÃ³mico Nacional in San Pedro MÃ¡rtir.


GRB_name: GRB220412A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31899
SUBJECT: GRB 220412A: Swift-BAT refined analysis
DATE:    22/04/13 21:01:24 GMT
FROM:    Tyler Parsotan at UMBC/GSFC/CRESST II  <parsotat@umbc.edu>

T. Parsotan (GSFC/UMBC), S. D. Barthelmy (GSFC), 

H. A. Krimm (NSF), S. Laha (GSFC/UMBC),

A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),

D. M. Palmer (LANL), 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 220412A (trigger #1102281)

(Klingler et al. GCN Circ. 31881).  The BAT ground-calculated position is

RA, Dec = 123.975, 30.336 deg which is 

   RA(J2000)  =  08h 15m 54.0s 

   Dec(J2000) = +30d 20' 08.5" 

with an uncertainty of 1.9 arcmin, (radius, sys+stat, 90% containment).

The partial coding was 92%.

 

The BAT light curve showed a complex

structure with a duration of about 20 sec.  The peak count rate

was ~900 counts/sec (15-350 keV), at ~1 sec after the trigger.

T90 (15-350 keV) is 41.66 +- 7.00 sec (estimated error including systematics).

 

The time-averaged spectrum from T-11.07 to T+38.00 sec is best fit by a simple

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

1.53 +- 0.21.  The fluence in the 15-150 keV band is 5.9 +- 0.9 x 10^-07 erg/cm2.

The 1-sec peak photon flux measured from T+6.88 sec in the 15-150 keV band

is 0.5 +- 0.1 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/1102281/BA/

 

 


GRB_name: GRB220412B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31900
SUBJECT: GRB 220412B: BOOTES-1 optical upper limit
DATE:    22/04/14 00:04:34 GMT
FROM:    Youdong HU at IAA-CSIC  <huyoudong072@hotmail.com>

Y.-D. Hu, E. Fernandez-Garcia, T.-R. Sun, A. J. Castro-Tirado, M. D. Caballero-Garcia, R. Sanchez-Ramirez (IAA-CSIC),  C. Perez del Pulgar,  A. Castellon, I. Carrasco, A. Reina (Univ. de Malaga) and F. Rendon (IAA-CSIC and INTA-CEDEA) on behalf of a larger collaboration, report:

Following the detection of short GRB 220412B by Swift (Gropp et al., GCNC 31886), the 0.3m BOOTES-1B robotic telescope in Mazagon (Huelva), southern Spain, automatically responded to this burst on Apr 13 at 03:46 UT (~10.7 hours after trigger). In the co-added frame (45 x 60 s, clear filter), no source is detected within the BAT error box (Gropp et al., GCNC 31886) down to 18.8 mag, which is consistent with the non-detections reported by UVOT (Gropp et al., GCNC 31886), MITSuME (Murata et al. GCNC 31889), GIT (Kumar et al. GCNC 31892) and MASTER (Lipunov et al., GCNC 31894).

We thank the staff at INTA-CEDEA for their excellent support.


GRB_name: GRB220412A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31901
SUBJECT: GRB 220412A: BOOTES-network optical upper limits
DATE:    22/04/14 00:05:31 GMT
FROM:    Youdong HU at IAA-CSIC  <huyoudong072@hotmail.com>

Y.-D. Hu, E. Fernandez-Garcia, A. J. Castro-Tirado, T.-R. Sun, M. D. Caballero-Garcia, R. Sanchez-Ramirez (IAA-CSIC),  D. Hiriart and W. H. Lee (UNAM), C. Perez del Pulgar,  A. Castellon, I. Carrasco, A. Reina (Univ. de Malaga), I. H. Park (SKKU) and F. Rendon (IAA-CSIC and INTA-CEDEA) on behalf of a larger collaboration, report:

Following the detection of GRB 220412A by Swift (Klingler et al., GCNC 31881), the 0.3m BOOTES-1B robotic telescope in Mazagon (Huelva), southern Spain, automatically responded to this burst on Apr 12 at 22:41 UT (i.e. ~16.1 hours after trigger). In the co-added frame (52 x 60 s, clear filter), no source is detected within the enhanced XRT position (Evans et al., GCNC 31887) down to 19.2 mag.

Later on, the 60cm BOOTES-5/JGT robotic telescope at Observatorio Astronomico Nacional in San Pedro Martir (Mexico) automatically responded to this burst on Apr 13 at 03:33 UT (i.e. ~ 21 hrs after trigger). In the co-added image (45 x 60 s, clear filter), no optical afterglow is detected within the enhanced XRT position (Evans et al., GCNC 31887) down to 20.3 mag.

Although the candidate reported by RATIR (Watson et al. GCNC 31882, GCNC 31898) is not detected, those non-detections are consistent with the reports from Swift/UVOT (Klingler et al., GCNC 31881, Breeveld et al. GCNC 31885), MITSuME (Murata et al. GCNC 31891) and MASTER-Net (Lipunov et al., GCNC 31880).

We thank the staff at INTA-CEDEA and San Pedro Martir Observatory for their excellent support.


GRB_name: GRB220412A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31902
SUBJECT: GRB 220412A: Continued RATIR Observations and Steepening of the Light Curve 
DATE:    22/04/14 20:00:57 GMT
FROM:    Alan M Watson at UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Eleonora Troja (UTV), Alexander Kutyrev
(GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J.
Xavier Prochaska (UCSC), Josh Bloom (UCB), Enrico Ramirez-Ruiz (UCSC), JesÃºs
GonzÃ¡lez (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Harvey Moseley (GSFC), Rosa L.
Becerra (UNAM), Simone Dichiara (PSU), and OcÃ©lotl LÃ³pez (UNAM) report:

We observed the field of GRB 220412A (Klingler et al. GCN 31881) with the
Reionization and Transients Infrared Camera (RATIR) on the 1.5m Harold Johnson
Telescope at the Observatorio AstronÃ³mico Nacional on Sierra San Pedro MÃ¡rtir
from 2022-04-14 03:28 to 07:30 UTC (44.9 to 48.9 hours after the trigger)
obtaining 2.31 hours of exposure in the i band.

In comparison with the SDSS DR9 catalog, the afterglow candidate reported by
Watson et al. (GCN Circ. 31882, 31898) is detected at i = 21.51 +/- 0.10.

We note that the optical light curve appears to have steepened. The temporal
index between our observations at 21 hours (Watson et al., GCN Circ 31898) and
47 hours is close to -1.0.

Further observations are continuing.

We thank the staff of the Observatorio AstronÃ³mico Nacional in San Pedro MÃ¡rtir.


GRB_name: GRB220412A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31903
SUBJECT: GRB 220412A: GRANDMA observations
DATE:    22/04/15 12:13:31 GMT
FROM:    Patrice Hello at LAL  <hello@lal.in2p3.fr>

Subject Line:
GRB 220412A: GRANDMA observations

Content:

S. Beradze (AbAO), U. Bhardwaj (GRAPPA), T. Culino (ESILV), P. Hello
(IJCLAB), M. Masek (FZU), G. Raaijmakers (GRAPPA), Y. Rajabov (UBAI),
T. Sadibekova (AIM/CEA-UPS), F. Z. Guo (THU), X. F. Wang (THU/BJP), Y.
Zhu (NAOC), J. Zhang (NAOC), D. A. Kann (HETH/IAA-CSIC), K. Noysena
(NARIT), A. Kaouech (OUCA/KNC) C. Rinner (OUCA), Z. Benkhaldoun (OUCA),
S. Antier (OCA/Artemis), P. A. Duverne (IJCLAB), M. Freeberg (KNC),
R. Hainich (UP), F. Runger (UP), S. Karpov (FZU), A. Simon (Kyiv Univ),
A. Baransky (Kyiv Univ) and V. Godunova (IC ICAMER)
report on behalf of GRANDMA collaboration:

The GRANDMA telescope network responded to the alert of GRB 220412A
(N. J. Klingler et al. GCNC 31881, P.A. Evans et al. GCN 31887,
A. D'Ai et al. GCN 31888, K.L. Page et al GCN 31890).
The first observations started ** h after the SWIFT BAT trigger time.

We did not detect the optical afterglow within the first 24 h.
Upper limits are given in the AB system, at 3-sigma.


T-T0(hr)| MJD    | Observatory  | Exposure| Filter | Upp. Lim. (AB)
_____________________________________________________
05.55 |59681.50689|Xinglong-2.16m|12*300s    |  R     |   19.5
14.02 |59681.86193|OST/CDK20     |18*180s    |  R     |   17.8
14.07 |59681.85977|OST/CDK20     |17*180s    |  I     |   17.0
17.36 |59681.99881|KNC-HAO       |5*180s     |  L      |   17.3
21.18 |59682.15807|TRT-SRO       |10*60s     |  V       |   18.1
21.35 |59682.16537|TRT-SRO       |10*60s     |  R       |   17.7
21.53 |59682.17271|TRT-SRO       |10*60s     |  I       |   17.1
21.95 |59682.19014|KNC-T24       |3300s      |  I       |   18.1


The observations were contaminated by the moon.

These upper limits are consistent with previous reports of detections by
RATIR (Alan M. Watson et al., GCN 31882 & GCN 31902) and the upper limits
provided by UVOT (A. Breeveld and N. Klingler, GCN 31885), MITSuME Akeno
(K. L. Murata et al., GCN 31891).


The Xinglong-2.16m and TRT-SRO data have been calibrated using nearby stars
from the Pan-STARRS catalog. The measurements for  Xinglong-2.16m provided
by the STDPipe pipeline (Karpov 2022). The OST data have been using CDK
filter and calibrated with USNO-B1.0 Catalog (Monet+ 2003). The KNC-T24 and
KNC-HAO images have been calibrated using field stars from the 
PanSTARRS-DR1
catalog, measured with the MUPHOTEN pipeline (Duverne et al. 2021).


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: GRB220412B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31904
SUBJECT: GRB 220412B: TNG optical observations
DATE:    22/04/15 17:08:31 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <pda.davanzo@gmail.com>

P. D'Avanzo (INAF-OAB), S. Piranomonte (INAF-OAR), L. Di Fabrizio, H. Stoev (INAF-TNG) on behalf of the CIBO collaboration report:

We observed the field of the short GRB 220412B (Gropp et al. GCN Circ. 31886) with the Italian 3.6m TNG telescope equipped with the 
optical camera DOLORES. A series of images were obtained with the r-sdss filter on 2022-04-13 from 04:42:48 UT to 05:26:37 UT 
(i.e. at a mid time of about 12 hours after the burst).  

No clear afterglow candidate is detected within the BAT error (Gropp et al. GCN Circ. 31886). The typical 3sigma limiting magnitude of 
our co-added image for isolated objects is r ~ 24.2 mag (AB; calibrated against the SDSS catalogue). 


GRB_name: GRB220408B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31905
SUBJECT: Konus-Wind detection of GRB 220408B
DATE:    22/04/15 18:11:24 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

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

The long-duration GRB 220408B
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 31854;
AstroSat-CZTI detection: Gopalakrishnan et al., GCN Circ. 31863;
IPN triangulation: Kozyrev et al., GCN Circ. 31878;
Fermi-LAT detection: Bissaldi et al., GCN Circ. 31896;)
triggered Konus-Wind at T0=26885.231 s UT (07:28:05.231).

The burst light curve shows a multipeaked structure
which starts at ~T0-0.5 s and has a total duration of ~35 s.
The emission is seen up to ~3 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB220408_T26885/

As observed by Konus-Wind, the burst
had a fluence of 4.1(-0.4,+0.5)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+3.760 s,
of 7.26(-1.60,+1.63)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+30.976 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(-0.09,+0.11),
the high energy photon index beta = -2.72(-0.54,+0.29),
the peak energy Ep = 231(-20,+20) keV
(chi2 = 84/81 dof).

The spectrum near the maximum count rate
(measured from T0+0.256 to T0+6.400 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 = -0.27(-0.16,+0.18),
the high energy photon index beta = -2.39(-0.21,+0.15),
the peak energy Ep = 211(-20,+23) keV
(chi2 = 80/82 dof).

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


GRB_name: GRB220408B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31906
SUBJECT: GRB 220408B: Fermi GBM observation
DATE:    22/04/15 19:52:40 GMT
FROM:    Elisabetta Bissaldi at INFN,Bari  <elisabetta.bissaldi@ba.infn.it>

E. Bissaldi (Politecnico and INFN Bari) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:


"At 07:28:04.65 UT on 8 April 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220408B (trigger 671095689 / 220408311),
which was also detected by the AstroSat CZTI (Gopalakrishnan et al. 2022, GCN 31863),
Fermi-LAT (Bissaldi et al. 2022, GCN 31896), and Konus-Wind (Lysenko et al. 2022,
GCN 31905).
The Fermi GBM Final Localization (GCN 31854) is consistent with the LAT position.

The angle from the Fermi LAT boresight at the GBM trigger time is 29 degrees.

The GBM light curve consists of multiple peaks
with a duration (T90) of about 33 s (50-300 keV).
The time-averaged spectrum from T0 to T0+33 s is
best fit by a Band function with Epeak = 214 +/- 8 keV,
alpha = -0.80 +/- 0.02 and beta = -2.33 +/- 0.09.

The event fluence (10-1000 keV) in this time interval is
(3.68 +/-  0.05)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+3.6 s in the 10-1000 keV band
is 17.1 +/- 0.3 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: GRB220403C
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31907
SUBJECT: Konus-Wind detection of GRB 220403C
DATE:    22/04/15 20:20:51 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 bright, long-duration GRB 220403C
(Swift/BAT-GUANO detection: Tohuvavohu et. al, GCN Circ. 31824;
IPN triangulation: Kozyrev et al., GCN Circ. 31877)
triggered Konus-Wind at T0=36829.998 s UT (10:13:49.998).

The burst light curve shows multipeaked structure
which starts at ~T0-3 s and has a total duration of ~66 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/GRB220403_T36829/

As observed by Konus-Wind, the burst
had a fluence of 1.45(-0.20,+0.17)x10^-4 erg/cm2,
and a 64-ms peak flux, measured from T0+3.456 s,
of 2.81(-0.48,+0.47)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+64.512 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 = -1.12(-0.09,+0.10),
the high energy photon index beta = -1.86(-0.25,+0.11),
the peak energy Ep = 540(-130,+254) keV
(chi2 = 86/82 dof).

The spectrum near the maximum count rate
(measured from T0+3.328 to T0+4.096 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 = -0.86(-0.09,+0.11),
the high energy photon index beta = -2.38(-0.97,+0.31),
the peak energy Ep = 835(-200,+240) keV
(chi2 = 60/56 dof).

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


GRB_name: GRB220412B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31908
SUBJECT: GRB 220412B: Fermi GBM observation
DATE:    22/04/15 20:33:00 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

P. Veres and C. Meegan (both UAH)
report on behalf of the Fermi GBM Team:

"At 17:06:49.04 UT on 12 April 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220412B (trigger 671476014 / 220412713)
which was also detected by the Swift/BAT (Gropp et al., GCN 31886).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 20 degrees.


The GBM light curve consists of a single pulse
with a duration (T90) of about 0.16 s (50-300 keV).
The time-averaged spectrum from T0-32 ms to T0+96 ms is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.70 +/-0.14 and
the cutoff energy, parameterized as Epeak, is 499 +/- 116 keV.

The event fluence (10-1000 keV) in this time interval is
(4.44 +/- 0.40)E-7 erg/cm^2. The 64-ms peak photon flux measured
starting from T0 in the 10-1000 keV band
is 17.2 +/- 1.2 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: GRB220412B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31909
SUBJECT: Konus-Wind detection of GRB 220412B
DATE:    22/04/15 22:23:55 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 220412B
(Swift-BAT detection: Gropp et al., GCN Circ. 31886;
Fermi-GBM observation: Veres and Meegan, GCN Circ. 31908)
triggered Konus-Wind at T0=26885.231 s UT (07:28:05.231).

The burst light curve shows a single pulse
with a total duration of ~86 ms.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB220412_T61606/

As observed by Konus-Wind, the burst
had a fluence of 3.2(-0.1,+1.2)x10^-7 erg/cm2,
and a 16-ms peak flux, measured from T0-42 ms,
of 1.1(-0.1,+0.4)x10^-5 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

Since the main fraction of the burst emission was detected
before the trigger, the spectral analysis was performed using
the KW 3-channel light curve data.

Modelling the KW 3-channel time-integrated spectrum
(measured from T0-52 ms to T0+34 ms)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep),
yields alpha = -0.03(-0.47,+0.59) and Ep = 283(-52,+68) keV.

All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.


GRB_name: GRB220412B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31910
SUBJECT: GRB 220412B: Swift-BAT refined analysis
DATE:    22/04/16 12:16:02 GMT
FROM:    Tyler Parsotan at UMBC/GSFC/CRESST II  <parsotat@umbc.edu>

T. Sakamoto (AGU), S. D. Barthelmy (GSFC), 

H. A. Krimm (NSF), S. Laha (GSFC/UMBC),

A. Y. Lien (U Tampa), C. B. Markwardt (GSFC),

D. M. Palmer (LANL), T. Parsotan (GSFC/UMBC),

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

 

Using the data set from T-240 to T+40 sec sec from the recent telemetry downlink,

we report further analysis of BAT GRB 220412B (trigger #1102329)

(Gropp et al. GCN Circ. 31886).  The BAT ground-calculated position is

RA, Dec = 320.758, -0.261 deg which is 

   RA(J2000)  =  21h 23m 01.9s 

   Dec(J2000) = -00d 15' 38.5" 

with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).

The partial coding was 75%.

 

The BAT light curve showed a single-peaked

structure. T90 (15-350 keV) is 0.14 +- 0.04 sec 

(estimated error including systematics).

 

The time-averaged spectrum from T-0.03 to T+0.16 sec is best fit by a simple

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

1.17 +- 0.20.  The fluence in the 15-150 keV band is 8.9 +- 1.2 x 10^-08 erg/cm2.

The 1-sec peak photon flux measured from T-0.44 sec in the 15-150 keV band

is 1.0 +- 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/1102329/BA/

 


GRB_name: GRB220417A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31912
SUBJECT: GRB 220417A: Fermi GBM Final Real-time Localization
DATE:    22/04/17 14:04:01 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 13:52:35 UT on 17 Apr 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220417A (trigger 671896360.964484 / 220417578).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 107.7, Dec = 11.3 (J2000 degrees, equivalent to J2000 07h 10m, 11d 18'), with a statistical uncertainty of 8.2 degrees.

The angle from the Fermi LAT boresight is 99.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220417578/quicklook/glg_skymap_all_bn220417578.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220417578/quicklook/glg_healpix_all_bn220417578.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220417578/quicklook/glg_lc_medres34_bn220417578.gif


GRB_name: GRB220417A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31913
SUBJECT: Fermi GRB 220417A: Global MASTER-Net observations report 
DATE:    22/04/17 17:30:19 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-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 220417A ( Fermi GBM team, GCN 31912) errorbox  10933 sec after notice time and 10962 sec after trigger time at 2022-04-17 16:55:18 UT, with upper limit up to  18.2 mag. Observations started at twilight.  The observations began at zenith distance = 43 deg. The sun  altitude  is -9.1 deg. 

The galactic latitude b = 10 deg., longitude l = 205 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1945725

We obtain a following upper limits.  

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

   10992 | 2022-04-17 16:55:18 |         MASTER-SAAO | (07h 06m 38.28s , +08d 45m 24.4s) |   C |    60 | 15.9 |        
   11072 | 2022-04-17 16:56:38 |         MASTER-SAAO | (07h 14m 48.63s , +08d 45m 35.3s) |   C |    60 | 16.3 |        
   11163 | 2022-04-17 16:58:09 |         MASTER-SAAO | (07h 09m 06.34s , +10d 41m 17.1s) |   C |    60 | 16.4 |        
   11254 | 2022-04-17 16:59:40 |         MASTER-SAAO | (06h 59m 49.61s , +14d 29m 20.8s) |   C |    60 | 16.4 |        
   11334 | 2022-04-17 17:00:59 |         MASTER-SAAO | (07h 07m 58.48s , +14d 28m 42.2s) |   C |    60 | 16.7 |        
   11509 | 2022-04-17 17:03:54 |         MASTER-SAAO | (07h 17m 16.46s , +10d 40m 40.1s) |   C |    60 | 17.0 |        
   11600 | 2022-04-17 17:05:25 |         MASTER-SAAO | (07h 11m 57.99s , +12d 33m 45.2s) |   C |    60 | 17.1 |        
   11679 | 2022-04-17 17:06:45 |         MASTER-SAAO | (07h 20m 15.06s , +12d 34m 06.3s) |   C |    60 | 17.2 |        
   11771 | 2022-04-17 17:08:16 |         MASTER-SAAO | (06h 56m 29.96s , +12d 35m 39.7s) |   C |    60 | 17.2 |        
   11862 | 2022-04-17 17:09:47 |         MASTER-SAAO | (07h 04m 41.19s , +12d 34m 13.1s) |   C |    60 | 17.4 |        
   11942 | 2022-04-17 17:11:07 |         MASTER-SAAO | (07h 06m 46.87s , +08d 47m 40.7s) |   C |    60 | 17.5 |        
   12033 | 2022-04-17 17:12:38 |         MASTER-SAAO | (07h 14m 45.42s , +08d 46m 56.4s) |   C |    60 | 17.6 |        
   12112 | 2022-04-17 17:13:58 |         MASTER-SAAO | (07h 09m 05.17s , +10d 42m 00.2s) |   C |    60 | 17.8 |        
   12204 | 2022-04-17 17:15:29 |         MASTER-SAAO | (06h 59m 51.07s , +14d 29m 07.7s) |   C |    60 | 17.9 |        
   12283 | 2022-04-17 17:16:49 |         MASTER-SAAO | (07h 08m 01.35s , +14d 28m 11.3s) |   C |    60 | 17.9 |        
   12374 | 2022-04-17 17:18:20 |         MASTER-SAAO | (06h 53m 42.16s , +10d 41m 56.9s) |   C |    60 | 18.0 |        
   12465 | 2022-04-17 17:19:50 |         MASTER-SAAO | (07h 01m 50.54s , +10d 40m 34.4s) |   C |    60 | 18.0 |        
   12545 | 2022-04-17 17:21:10 |         MASTER-SAAO | (07h 17m 19.52s , +10d 42m 11.5s) |   C |    60 | 18.2 |        
   12635 | 2022-04-17 17:22:40 |         MASTER-SAAO | (07h 12m 01.86s , +12d 35m 19.6s) |   C |    60 | 18.1 |        
   12714 | 2022-04-17 17:24:00 |         MASTER-SAAO | (07h 20m 13.43s , +12d 36m 22.8s) |   C |    60 | 18.2 |        
Filter C is a clear (unfiltred) band. 


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


GRB_name: GRB220418A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31914
SUBJECT: GRB 220418A: Fermi GBM Final Real-time Localization
DATE:    22/04/18 16:03:22 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 15:51:58 UT on 18 Apr 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220418A (trigger 671989923.878466 / 220418661).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 334.3, Dec = 62.0 (J2000 degrees, equivalent to J2000 22h 17m, 62d 00'), with a statistical uncertainty of 7.8 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/2022/bn220418661/quicklook/glg_skymap_all_bn220418661.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220418661/quicklook/glg_healpix_all_bn220418661.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220418661/quicklook/glg_lc_medres34_bn220418661.gif


GRB_name: GRB220418B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31915
SUBJECT: GRB 220418B: Fermi GBM Final Real-time Localization
DATE:    22/04/18 17:26:38 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 SHORT GRB

At 17:16:21 UT on 18 Apr 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220418B (trigger 671994986.650868 / 220418720).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 216.5, Dec = -26.6 (J2000 degrees, equivalent to J2000 14h 26m, -26d 36'), with a statistical uncertainty of 29.8 degrees.

The angle from the Fermi LAT boresight is 90.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220418720/quicklook/glg_skymap_all_bn220418720.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220418720/quicklook/glg_healpix_all_bn220418720.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220418720/quicklook/glg_lc_medres34_bn220418720.gif


GRB_name: GRB220418A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31916
SUBJECT: Fermi GRB 220418A: Global MASTER-Net observations report 
DATE:    22/04/18 18:15:38 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 220418A ( Fermi GBM team, GCN 31914) errorbox  7665 sec after notice time and 7697 sec after trigger time at 2022-04-18 18:00:16 UT, with upper limit up to  13.9 mag. The observations began at zenith distance = 75 deg. The sun  altitude  is -20.9 deg. 

The galactic latitude b =  4 deg., longitude l = 106 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1946689

We obtain a following upper limits.  

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

    7727 | 2022-04-18 18:00:16 |   MASTER-Kislovodsk | (22h 05m 59.24s , +61d 57m 24.4s) |   C |    60 | 13.9 |        
Filter C is a clear (unfiltred) band. 


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


GRB_name: GRB220412B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31917
SUBJECT: GRB 220412B: Swift/UVOT Upper Limits
DATE:    22/04/19 01:41:07 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <mhs18@psu.edu>

M. H. Siegel and J. D. Gropp (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 220412B
89 s after the BAT trigger (Gropp et al., GCN Circ. 31886).
No optical afterglow consistent with the BAT position
(Sakamoto et al., GCN Circ. 31910) 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

white (fc)          89          217          128         >20.0
white             4378         4577          197         >20.3
b                 4173         4373          197         >19.8
u                 3968         4167          197         >19.4
w2                4584         4663           78         >19.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.060 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB220417A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31918
SUBJECT: GRB 220417A: Swift/BAT-GUANO detection outside the coded FOV
DATE:    22/04/19 05:16:43 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>

Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), James DeLaunay
(UAlabama), Jamie A. Kennea (PSU), report:

Swift/BAT did not localize GRB 220417A onboard (T0:
2022-04-17T13:52:35 UTC, Fermi/GBM trig #671896360).

The Fermi notice, 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,
arXiv:2111.01769), detects the burst with a sqrt(TS) of 12.8 in a
8.192 s analysis time bin.
The burst episode as seen by BAT is ~8s long.

NITRATES results are consistent with a burst coming from outside the
coded FoV, as indicated by the Fermi/GBM localization (GCN 31912).

See Section 9.1 and Figure 20 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: GRB220418B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31919
SUBJECT: GRB 220418B: Swift/BAT-GUANO candidate arcminute localization of a short burst
DATE:    22/04/19 05:52:20 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>

Aaron Tohuvavohu (U Toronto), James DeLaunay (UAlabama), Gayathri
Raman (PSU), Jamie A. Kennea (PSU), report:

Swift/BAT did not localize GRB 220418B onboard (T0:
2022-04-18T17:16:21 UTC, Fermi/GBM trig #671994986).

The Fermi notice, 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,
arXiv:2111.01769), detects the burst in a 2.048 s analysis time bin
with a sqrt(TS) of 10.4.

A candidate arcminute localization is found with DeltaLLHPeak of 11.8.

See Section 9.1 and Figure 20 in the NITRATES paper for brief
descriptions and interpretations of sqrt(TS), DeltaLLHPeak, and
DeltaLLHOut.

The BAT position is
RA, Dec = 224.329, -17.514 deg which is
   RA(J2000)  = 14h 57m 18.96s
   Dec(J2000) = -17d 30â€² 15.4â€³
with an estimated uncertainty of 5 arcmin.

This position is consistent with the Fermi/GBM localization (GCN 31915).

XRT and UVOT follow-up has been requested, but will be delayed due to
the position's proximity to the Moon.
We encourage prompt followup from other facilities.

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: GRB220411A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31920
SUBJECT: IPN triangulation of GRB 220411A
DATE:    22/04/19 10:07:29 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 HEND/Mars-Odyssey team,

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

A. Goldstein, M. S. Briggs, and C. Wilson-Hodge
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 220411A
(Fermi-GBM detection: The Fermi GBM team, GCN Circ. 31871;
BALROG localization: Kunzweiler et al., GCN Circ. 31872;
AstroSat CZTI detection: Gopalakrishnan et al., GCN Circ. 31879)
was detected by Fermi (GBM trigger 671354405), INTEGRAL (SPI-ACS),
Konus-Wind, Mars-Odyssey (HEND), and AstroSat (CZTI)
at about 26401 s UT (07:20:01).

We have triangulated it to a SPI-ACS-HEND annulus centered at
RA(2000)=149.487 deg (09h 57m 57s)  Dec(2000)=+13.850 deg (+13d 50' 59"),
whose radius is 30.455 +/- 0.229 deg (3 sigma).

The Fermi GBM Final Real-time (GCN Circ. 31871) and
BALROG (GCN Circ. 31872) localizations are consistent with the annulus.
The annulus combined with the BALROG localization
gives the following error box:
------------------------------------------------------------
   RA(2000), deg                 Dec(2000), deg
------------------------------------------------------------
  Center:
   179.643 (11h 58m 34s) +25.001 (+25d 00' 04")
  Corners:
   176.853 (11h 47m 25s) +31.565 (+31d 33' 54")
   176.353 (11h 45m 25s) +31.390 (+31d 23' 26")
   180.657 (12h 02m 38s) +18.050 (+18d 03' 01")
   181.134 (12h 04m 32s) +18.133 (+18d 07' 57")
------------------------------------------------------------
The error box area is 6.4 sq. deg, and its maximum
dimension is 14 deg (the minimum one is 27 arcmin).
The Sun distance was 134 deg.

This box may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220411_T26405/IPN

The time history and spectrum will be given in forthcoming GCN Circulars.


GRB_name: GRB220418B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31921
SUBJECT: GRB 220418B: Swift/BAT-GUANO refined location of a short burst
DATE:    22/04/19 13:26:14 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>

James DeLaunay (UAlabama), Aaron Tohuvavohu (U Toronto), Gayathri
Raman (PSU), Jamie A. Kennea (PSU), report:

Further analysis has improved the location of the short GRB reported
in GCN 31919, and its confidence.
This new position is fully consistent with the originally reported
position, with a smaller uncertainty region.

The BAT position is
RA, Dec = 224.344 -17.539 deg which is
   RA(J2000)  = 14h 57m 22.56s
   Dec(J2000) = -17d 32â€² 20.4â€³
with an estimated uncertainty of 3 arcmin.

We encourage followup from other instruments.


GRB_name: GRB220417A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31922
SUBJECT: GRB 220417A: Fermi GBM detection
DATE:    22/04/19 18:56:31 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

R. Hamburg (UAH) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 13:52:35.96 UT on 17 April 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220417A (trigger 671896360 / 220417578),
which was also detected by the Swift/BAT-GUANO (Raman et al. 2022,
GCN 31918).

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

The GBM light curve shows a single peak with a duration (T90) of
about 17 s (50-300 keV). The time-averaged spectrum from T0-5.1 s
to T0+5.1 s is adequately fit by a power law function with an
exponential high-energy cutoff.  The power law index is
0.51 +/- 0.57 and the cutoff energy, parameterized as Epeak,
is 431 +/- 97 keV.

The event fluence (10-1000 keV) in this time interval is
(2.5 +/- 0.4)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.3 s in the 10-1000 keV band is 1.3 +/- 0.2
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: GRB220418B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31923
SUBJECT: GRB 220418B: Swift ToO observations
DATE:    22/04/20 00:54:19 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 ToO observation of the Swift/BAT-GUANO GRB 220418B. 
Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021486

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Swift/BAT-GUANO event. 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: GRB220403C
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31924
SUBJECT: GRB 220403C: Further Swift-XRT observations
DATE:    22/04/20 08:07:27 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), D.N. Burrows (PSU),
J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A. Melandri
(INAF-OAB), T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB) and P.A.
Evans (U. Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed a second follow-up observation of GRB 220403C,
detected outside the BAT coded FOV by GUANO NITRATES (Aaron Tohuvavohu
et al. GCN Circ. 31824), and later triangulated by IPN (GCN Circ.
31877). This time the XRT pointed at the centre of the IPN error
region, collecting 2.5 ks of Photon Counting (PC) mode data between
T0+1311.3 ks and T0+1324.1 ks. 

Two uncatalogued X-ray sources have been detected, however neither of
them is above the RASS limit or shows definitive signs of fading.
Therefore, at the present time we cannot identify which, if either, is
the afterglow. Details of these sources are given below:

Source 1:
  RA (J2000):  17.5547  =  01:10:13.12
  Dec (J2000): -56.2345  =  -56:14:04.2
  Error: 5.5 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (5.7 [+2.0, -1.6])e-3 ct s^-1   
  Distance: 46 arcsec from IPN position.
  Flux: (6.8 [+2.4, -2.0])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 2:
  RA (J2000):  17.9074  =  01:11:37.77
  Dec (J2000): -56.1775  =  -56:10:38.9
  Error: 9.7 arcsec (radius, 90% conf.)
  Count-rate: (5.0 [+3.2, -2.3])e-3 ct s^-1   
  Distance: 695 arcsec from IPN position.

We note that neither of these sources is consistent with the location
of the galaxy LEDA 3080270 which lies within the IPN error box.

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/00021485.

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


GRB_name: GRB220420A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31925
SUBJECT: GRB 220420A: Swift/BAT-GUANO detection outside the coded FOV
DATE:    22/04/20 15:26:11 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>

Jamie A. Kennea (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U
Toronto), James DeLaunay (UAlabama) report:

Swift/BAT did not localize GRB 220420A onboard (T0:
2022-04-20T03:54:31.9 UTC, CALET trig #1334461972, INTEGRAL/SPI-ACS
trig #9861).

The CALET and INTEGRAL 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 108 seconds of BAT event-mode data from
[-45,+63] 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,
arXiv:2111.01769), detects the burst with a sqrt(TS) of 65.8 in a
16.384 s analysis time bin.
The burst episode as seen by BAT is ~60s long.

NITRATES results strongly indicate a burst coming from outside the
coded FoV, with DeltaLLHOut of -489.

See Section 9.1 and Figure 20 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: GRB220418B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31928
SUBJECT: GRB 220418B Fermi GBM observation
DATE:    22/04/21 01:25:04 GMT
FROM:    Cori Fletcher at USRA  <cfletcher@usra.edu>

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

"At 17:16:21.65 UT on 18 April 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220418B (trigger 671994986 / 220418720).
which was also detected by the Swift-BAT/GUANO (GCN 31919, 31921)
The Fermi GBM Final Real-time Localization (GCN 31915) is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 80 degrees.

The GBM light curve shows a single peak
with a duration (T90) of about 1.7 s (50-300 keV).
The time-averaged spectrum from T0-1.024 s to T0+1.024 s is
best fit a simple power law function with index -1.6 +/- 0.1.

The event fluence (10-1000 keV) in this time interval is
(3.8 +/- 0.6)E-07 erg/cm^2. The 64-ms peak photon flux measured
starting from T0-0.57 s in the 10-1000 keV band
is 121 +/- 76 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: GRB220418B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31930
SUBJECT: GRB 220418B: Swift-XRT observations
DATE:    22/04/21 09:32:41 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

B. Sbarufatti (PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester),
K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), T. Sbarrato
(INAF-OAB), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), J. D.
Gropp (PSU) and P.A. Evans (U. Leicester) report on behalf of the
Swift-XRT team:

Swift-XRT has performed follow-up observations of the
Swift/BAT-GUANO-detected burst GRB 220418B, collecting 4.8 ks of Photon
Counting (PC) mode data between T0+113.8 ks and T0+148.8 ks. These
observations were delayed due to the Moon observing constraint.

Due to a high XRT temperature and consequent high background, the data
contain many low significance detections (ranked as "poor") which are
likely to be spurious, but no objects are detected within the BAT/GUANO
error region. We therefore conclude that no XRT afterglow to this
object has been found.

The 3-sigma upper limit is 2.3e-3 ct/sec, which, assuming a typical GRB
spectral, equates to an observed 0.3-10 keV flux of ~9e-14 erg/cm^2/s.

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/00021486.

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


GRB_name: GRB220421A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31934
SUBJECT: GRB 220421A: Swift/BAT-GUANO detection outside the coded FOV
DATE:    22/04/21 21:25:41 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>

Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), James DeLaunay
(UAlabama), Jamie A. Kennea (PSU), report:

Swift/BAT did not localize GRB 220421A onboard (T0:
2022-04-21T08:17:54.5 UTC, CALET trig #1334564169, Fermi/GBM trig
#672221879).

The CALET and Fermi 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,
arXiv:2111.01769), detects the burst with a sqrt(TS) of 34.7 in a
4.096 s analysis time bin.
The burst episode as seen by BAT is ~10s long.

NITRATES results indicate a burst coming from outside the coded FoV,
with DeltaLLHOut of -25. An out of FOV origin is consistent with the
Fermi/GBM localization.

See Section 9.1 and Figure 20 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: GRB220421A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31936
SUBJECT: GRB 220421A: Fermi GBM observation
DATE:    22/04/23 15:07:33 GMT
FROM:    Andreas von Kienlin at MPE  <azk@mpe.mpg.de>

A. von Kienlin (MPE) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 08:17:54.53 UT on 21 April 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220421A (trigger 672221879/220421346), which was
also 
detected by the Swift/BAT-GUANO (Raman et al. 2022, GCN 31934)

The on-ground calculated location, using the GBM trigger
data, is RA = 74.4, DEC = 23.1 (J2000 degrees,
equivalent to 04 h 57 m, 23 d 06 '), with a statistical uncertainty
of 2.1 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 59
degrees.

The GBM light curve shows a single pulse with a duration (T90) of about 6.4
s (50-300 keV).
The time-averaged spectrum from T0+0.002 s to T0+7.008 s is best fit by a
Band function 
with Epeak = 133.20 +/- 5.40 keV, alpha = -0.41 +/- 0.05, and beta = -2.48
+/- 0.11

The event fluence (10-1000 keV) in this time interval is
(7.2 +/- 0.2)E-06. The 1.024-sec peak photon flux measured
starting from T0+1.056 s in the 10-1000 keV band
is 13.2 +/- 0.3 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: GRB220421B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31937
SUBJECT: GRB 220421B: Detection by VZLUSAT-2
DATE:    22/04/23 15:55:15 GMT
FROM:    Jakub Ripa at Masaryk University  <ripa.jakub@mail.muni.cz>

J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), M. Ohno (Eotvos 
U./Hiroshima U.),  N. Werner  (Masaryk U.),  L. Meszaros (Konkoly 
Observatory), H. Takahashi (Hiroshima U.), B. Csak (Konkoly 
Observatory), M. Topinka, F. Munz, F. Hroch (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.

A GRB detected by GECAM (trigger at 2022-04-21 21:03:20.6 observation ID 
00035461090, https://www.swift.psu.edu/guano/) was also detected by both 
GRB detector units on board of the VZLUSAT-2 3U CubeSat 
(https://www.vzlusat2.cz/en/). Note that the reported GECAM trigger is 
~15s earlier than the onset of the GRB seen by VZLUSAT-2.

The data acquisition was performed by GRB detector units no. 0 and no. 
1. The 38 sigma detection significance was confirmed at 2022-04-21 
21:03:47 UTC. The long-duration GRB has the T90 duration of 62 s.

The light curve obtained by VZLUSAT-2 is available here:
https://vzlusat2.konkoly.hu/static/share/GRB220421B_GCN_VZLUSAT2.pdf

GRB detectors on VZLUSAT-2 are a demonstration payload for a future 
CubeSats 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: GRB220423A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31938
SUBJECT: GRB 220423A: AGILE detection
DATE:    22/04/23 16:27:04 GMT
FROM:    Alessandro Ursi at INAF/IAPS  <alessandro.ursi@gmail.com>

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

On its 15th birthday, the AGILE satellite detected the long GRB 220423A at
T0 = 2022-04-23 14:14:14 (UTC), reported by INTEGRAL SPI-ACS (trigger
no.9870) and CALET (trigger no.1334758343).

The burst is clearly visible in the AGILE scientific ratemeters of the
SuperAGILE (SA; 20-60 keV), MiniCALorimeter (MCAL; 0.4-100 MeV), and
AntiCoincidence (AC; 50-200 keV) detectors. The event lasted about 20 s and
it released a total number of 2150 counts in the SA detector (above a
background rate of 75 Hz), 36645 counts in the MCAL detector (above a
background rate of 1410 Hz), and 81820 counts in the AC detector (above a
background rate of 3220 Hz). The AGILE ratemeter light curves can be found
at http://www.agilescienceapp.it/notices/GRB220423A_AGILE_RM.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: GRB220423A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31939
SUBJECT: On the AGILE detection of GRB 220423A
DATE:    22/04/23 16:40:14 GMT
FROM:    Alessandro Ursi at INAF/IAPS  <alessandro.ursi@gmail.com>

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

We notice that today, April 23rd 2022, is the 15th anniversary of the AGILE
launch. The AGILE instrument has been flawlessly operating in orbit since
then. We take this opportunity to thank ASI, the AGILE scientific Team and
the ground segment team for their committment to the excellence of the
mission.


GRB_name: GRB220423A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31943
SUBJECT: GRB 220423A: Swift/BAT-GUANO detection outside the coded FOV
DATE:    22/04/24 02:21:14 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>

Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto), James DeLaunay
(UAlabama), Jamie A. Kennea (PSU), report:

Swift/BAT did not localize GRB 220423A onboard (T0: 2022-04-23T14:14:10
UTC, CALET trig #1334758343, INTEGRAL/SPI-ACS trig #9870, AGILE GCN 31938).

Happy Birthday AGILE!

The CALET and INTEGRAL 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 92 seconds of BAT event-mode data from [-46,+46]
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,
arXiv:2111.01769), detects the burst with a sqrt(TS) of 139 in a 8.192 s
analysis time bin.

The burst episode as seen by BAT is ~20s long.

NITRATES results strongly indicate a burst coming from outside the coded
FoV, with DeltaLLHOut of -734.

See Section 9.1 and Figure 20 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: GRB220421B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31949
SUBJECT: Correction to 31937: GRB 220421B: Detection by VZLUSAT-2
DATE:    22/04/25 16:52:18 GMT
FROM:    Jakub Ripa at Masaryk University  <ripa.jakub@mail.muni.cz>

J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), M. Ohno (Eotvos 
U./Hiroshima U.),  N. Werner  (Masaryk U.),  L. Meszaros (Konkoly 
Observatory), H. Takahashi (Hiroshima U.), B. Csak (Konkoly 
Observatory), M. Topinka, F. Munz, F. Hroch (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.

In Ripa et al. GCN 31937 we reported a detection of the GRB 220421B. 
Based on the GOES-16 and GOES-17 X-ray data the reported burst is 
probably not a GRB but a solar flare. The GOES X-ray light curves show a 
peak at 2022-04-21 21:04:00 UT which coincides with the peak in the rate 
curves from the GRB detectors on board the VZLUSAT-2 nanosatellite. The 
Sun was in the field of view of the VZLUSAT-2/GRB detectors.

We apologize for any inconvenience.


GRB_name: GRB220426A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31950
SUBJECT: GRB 220426A: BALROG localization (Fermi Trigger  672648596/ GRB 220426285)
DATE:    22/04/26 07:14:08 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 672648596
 at 06:49:51 on 26 April 2022 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) = 339.6+/-0.3 deg
Decl.(2000.0) = -24.0+/-0.3 deg
We estimate an additional systematic error of 2 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB220426285/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB220426285/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB220426285/json

                        


GRB_name: GRB220426B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31951
SUBJECT: GRB 220426B: Fermi GBM Final Real-time Localization
DATE:    22/04/26 07:20:50 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 07:10:36 UT on 26 Apr 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220426B (trigger 672649841.18156 / 220426299).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 138.4, Dec = -13.8 (J2000 degrees, equivalent to J2000 09h 13m, -13d 48'), with a statistical uncertainty of 5.2 degrees.

The angle from the Fermi LAT boresight is 55.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220426299/quicklook/glg_skymap_all_bn220426299.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220426299/quicklook/glg_healpix_all_bn220426299.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220426299/quicklook/glg_lc_medres34_bn220426299.gif


GRB_name: GRB220426B
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31952
SUBJECT: Fermi GRB 220426B: Global MASTER-Net observations report 
DATE:    22/04/26 07:30:38 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-OAGH robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) started inspect of the Fermi GRB 220426B ( Fermi GBM team, GCN 31951) errorbox  57 sec after notice time and 86 sec after trigger time at 2022-04-26 07:12:02 UT, with upper limit up to  17.6 mag. The observations began at zenith distance = 85 deg. The sun  altitude  is -45.5 deg. 

The galactic latitude b = 24 deg., longitude l = 244 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1954626

We obtain a following upper limits.  

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

      97 | 2022-04-26 07:12:02 |         MASTER-OAGH | (09h 02m 58.79s , -12d 12m 15.5s) |   C |    20 | 16.2 |        
      97 | 2022-04-26 07:12:02 |         MASTER-OAGH | (09h 02m 14.28s , -11d 43m 39.5s) |   C |    20 | 16.8 |        
     138 | 2022-04-26 07:12:43 |         MASTER-OAGH | (09h 02m 51.98s , -12d 13m 13.9s) |   C |    20 | 16.1 |        
     138 | 2022-04-26 07:12:43 |         MASTER-OAGH | (09h 02m 07.29s , -11d 44m 42.8s) |   C |    20 | 16.9 |        
     184 | 2022-04-26 07:13:24 |         MASTER-OAGH | (09h 02m 58.07s , -12d 12m 47.9s) |   C |    30 | 16.3 |        
     184 | 2022-04-26 07:13:24 |         MASTER-OAGH | (09h 02m 13.27s , -11d 44m 16.4s) |   C |    30 | 17.0 |        
     240 | 2022-04-26 07:14:16 |         MASTER-OAGH | (09h 02m 55.13s , -12d 11m 21.0s) |   C |    40 | 16.5 |        
     240 | 2022-04-26 07:14:16 |         MASTER-OAGH | (09h 02m 10.21s , -11d 42m 49.2s) |   C |    40 | 17.3 |        
     306 | 2022-04-26 07:15:17 |         MASTER-OAGH | (09h 02m 55.31s , -12d 13m 04.4s) |   C |    50 | 16.6 |        
     306 | 2022-04-26 07:15:17 |         MASTER-OAGH | (09h 02m 10.34s , -11d 44m 31.5s) |   C |    50 | 17.3 |        
     387 | 2022-04-26 07:16:28 |         MASTER-OAGH | (09h 02m 58.55s , -12d 11m 44.0s) |   C |    70 | 16.7 |        
     387 | 2022-04-26 07:16:28 |         MASTER-OAGH | (09h 02m 13.45s , -11d 43m 10.6s) |   C |    70 | 17.4 |        
     642 | 2022-04-26 07:20:18 |         MASTER-OAGH | (09h 14m 16.17s , -13d 48m 19.4s) |   C |   120 | 16.9 |        
     642 | 2022-04-26 07:20:18 |         MASTER-OAGH | (09h 13m 31.04s , -13d 19m 47.7s) |   C |   120 | 17.5 |        
     793 | 2022-04-26 07:22:39 |         MASTER-OAGH | (09h 13m 24.36s , -13d 20m 51.6s) |   C |   140 | 17.6 |        
     793 | 2022-04-26 07:22:39 |         MASTER-OAGH | (09h 14m 09.78s , -13d 49m 20.3s) |   C |   140 | 16.8 |        
Filter C is a clear (unfiltred) band. 


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


GRB_name: GRB220426A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31954
SUBJECT: GRB 220426A: Swift/BAT-GUANO detection outside the coded FOV
DATE:    22/04/26 19:00:41 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>

Aaron Tohuvavohu (U Toronto), Gayathri Raman (PSU),  James DeLaunay
(UAlabama), Jamie A. Kennea (PSU), report:

Swift/BAT did not localize GRB 220426A onboard (T0:
2022-04-26T06:49:51 UTC, Fermi/GBM trig #672648596, INTEGRAL/SPI-ACS
trig #9876).

The Fermi and INTEGRAL 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,
arXiv:2111.01769), detects the burst with a sqrt(TS) of 169 in a 4.096
s analysis time bin.
The burst episode as seen by BAT is ~6s long.

NITRATES results strongly indicate a burst coming from outside the
coded FoV, with DeltaLLHOut of -1550, consistent with the Fermi/GBM
BALROG localization (GCN 31950).

See Section 9.1 and Figure 20 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: GRB220426A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31955
SUBJECT: GRB 220426A: Fermi GBM detection
DATE:    22/04/26 19:42:53 GMT
FROM:    Christian Malacaria at NASA-MSFC/USRA  <cmalacaria@usra.edu>

C. Malacaria (USRA) and C. Meegan (UAH) report on behalf of the Fermi GBM Team:

At 06:49:51.23 UT on 26 April 2022, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 220426A (trigger 672648596 / 220426285).

The on-ground calculated location, using the GBM trigger data,
is RA = 335.8, DEC = -20.5 (J2000 degrees, equivalent
to 22h 23m, -20d 30'), with an uncertainty of 1.0 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 76 degrees.

The GBM light curve consists of a double pulse on top of a broader peak
with a duration (T90) of about 6 s (50-300 keV).
The time-averaged spectrum from T0+0.002 s to T0+9.856 s is
best fit by a Band function with Epeak = 146.3 +/- 0.9 keV,
alpha = -0.05 +/- 0.01, and beta = -3.08 +/- 0.04 .

The event fluence (10-1000 keV) in this time interval is
(1.084+/-0.005)E-04 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+3.9 s in the 10-1000 keV band
is 180.7 +/- 0.9 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: GRB220426A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31956
SUBJECT: Fermi GRB 220426A: Global MASTER-Net observations report 
DATE:    22/04/27 04:30:33 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-OAGH robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) started inspect of the Fermi GRB 220426A ( C. Malacaria et al., GCN 31955) errorbox  13914 sec after notice time and 13944 sec after trigger time at 2022-04-26 10:42:15 UT, with upper limit up to  18.2 mag. The observations began at zenith distance = 87 deg. The sun  altitude  is -23.6 deg. 

The galactic latitude b = -57 deg., longitude l = 33 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1954577

We obtain a following upper limits.  

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

   13974 | 2022-04-26 10:42:15 |         MASTER-OAGH | (22h 26m 58.35s , -22d 47m 13.6s) |   C |    60 | 14.0 |        
   13974 | 2022-04-26 10:42:15 |         MASTER-OAGH | (22h 18m 46.43s , -23d 14m 51.0s) |   C |    60 | 14.2 |        
   14195 | 2022-04-26 10:45:55 |         MASTER-OAGH | (22h 27m 04.78s , -22d 46m 50.5s) |   C |    60 | 14.4 |        
   14195 | 2022-04-26 10:45:55 |         MASTER-OAGH | (22h 18m 53.88s , -23d 14m 54.4s) |   C |    60 | 14.3 |        
   14416 | 2022-04-26 10:49:36 |         MASTER-OAGH | (22h 27m 01.55s , -22d 45m 08.6s) |   C |    60 | 14.7 |        
   14416 | 2022-04-26 10:49:36 |         MASTER-OAGH | (22h 18m 52.02s , -23d 13m 27.6s) |   C |    60 | 14.4 |        
   14638 | 2022-04-26 10:53:19 |         MASTER-OAGH | (22h 27m 01.61s , -22d 46m 16.7s) |   C |    60 | 15.0 |        
   14638 | 2022-04-26 10:53:19 |         MASTER-OAGH | (22h 18m 53.98s , -23d 13m 57.4s) |   C |    60 | 14.4 |        
   15069 | 2022-04-26 11:00:29 |         MASTER-OAGH | (22h 26m 59.82s , -22d 44m 34.8s) |   C |    60 | 13.5 |        
   15069 | 2022-04-26 11:00:29 |         MASTER-OAGH | (22h 18m 47.92s , -23d 13m 32.3s) |   C |    60 | 15.3 |        
   15399 | 2022-04-26 11:05:59 |         MASTER-OAGH | (22h 26m 59.62s , -22d 44m 54.8s) |   C |    60 | 16.0 |        
   15399 | 2022-04-26 11:05:59 |         MASTER-OAGH | (22h 18m 51.90s , -23d 13m 10.4s) |   C |    60 | 15.5 |        
   15621 | 2022-04-26 11:09:42 |         MASTER-OAGH | (22h 27m 05.08s , -22d 45m 53.1s) |   C |    60 | 15.9 |        
   15621 | 2022-04-26 11:09:42 |         MASTER-OAGH | (22h 18m 57.09s , -23d 14m 19.4s) |   C |    60 | 15.3 |        
   15843 | 2022-04-26 11:13:23 |         MASTER-OAGH | (22h 27m 00.35s , -22d 46m 49.8s) |   C |    60 | 16.0 |        
   15843 | 2022-04-26 11:13:23 |         MASTER-OAGH | (22h 18m 53.16s , -23d 14m 44.6s) |   C |    60 | 15.2 |        
   16335 | 2022-04-26 11:20:36 |         MASTER-OAGH | (22h 27m 03.19s , -22d 44m 58.7s) |   C |   180 | 16.9 |        
   16335 | 2022-04-26 11:20:36 |         MASTER-OAGH | (22h 18m 54.54s , -23d 13m 07.3s) |   C |   180 | 16.1 |        
   16677 | 2022-04-26 11:26:18 |         MASTER-OAGH | (22h 27m 03.75s , -22d 46m 34.8s) |   C |   180 | 18.1 |        
   16677 | 2022-04-26 11:26:18 |         MASTER-OAGH | (22h 18m 54.96s , -23d 14m 42.0s) |   C |   180 | 18.0 |        
   17018 | 2022-04-26 11:31:59 |         MASTER-OAGH | (22h 27m 07.01s , -22d 45m 21.0s) |   C |   180 | 18.2 |        
   17018 | 2022-04-26 11:31:59 |         MASTER-OAGH | (22h 18m 58.09s , -23d 13m 28.3s) |   C |   180 | 18.1 |        
   17360 | 2022-04-26 11:37:41 |         MASTER-OAGH | (22h 27m 01.27s , -22d 45m 58.8s) |   C |   180 | 18.2 |        
   17360 | 2022-04-26 11:37:41 |         MASTER-OAGH | (22h 18m 52.06s , -23d 14m 06.9s) |   C |   180 | 18.0 |        
   17703 | 2022-04-26 11:43:23 |         MASTER-OAGH | (22h 27m 02.75s , -22d 44m 59.6s) |   C |   180 | 17.6 |        
   17703 | 2022-04-26 11:43:23 |         MASTER-OAGH | (22h 18m 53.37s , -23d 13m 07.8s) |   C |   180 | 17.6 |        
   18045 | 2022-04-26 11:49:05 |         MASTER-OAGH | (22h 27m 08.28s , -22d 46m 00.6s) |   C |   180 | 16.9 |        
   18045 | 2022-04-26 11:49:05 |         MASTER-OAGH | (22h 18m 58.55s , -23d 14m 08.2s) |   C |   180 | 16.8 |        
Filter C is a clear (unfiltred) band. 


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


GRB_name: GRB220426C
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31957
SUBJECT: GRB 220426C: Swift/BAT-GUANO detection outside the coded FOV (short)
DATE:    22/04/27 14:10:41 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>

Jamie A. Kennea (PSU), Gayathri Raman (PSU), Aaron Tohuvavohu (U
Toronto), James DeLaunay (UAlabama), report:

Swift/BAT did not localize GRB 220426C onboard (T0:
2022-04-26T07:41:28.5 UTC, GECAM trig #utn220426_074128_GECAMb).

The GECAM notice, 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,
arXiv:2111.01769), detects the burst with a sqrt(TS) of 25.5 in a
1.024 s analysis time bin.
The burst episode as seen by BAT is ~1 s long.

NITRATES results indicate a burst coming from outside the coded FoV,
with DeltaLLHOut of -9.5.

See Section 9.1 and Figure 20 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: GRB220426A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31958
SUBJECT: IPN triangulation of GRB 220426A
DATE:    22/04/27 19:30:24 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, and C. Wilson-Hodge
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 220426A
(BALROG localization: Biltzinger et al., GCN Circ. 31950;
Swift/BAT-GUANO detection: Tohuvavohu et al., GCN Circ. 31954;
Fermi-GBM detection: Malacaria and Meegan, GCN Circ. 31955)
has been detected by Fermi (GBM trigger 672648596), INTEGRAL (SPI-ACS),
Swift (BAT), Konus-Wind, and Mars-Odyssey (HEND), so far,
at about 24591 s UT (06:49:51).
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:
   338.692 (22h 34m 46s) -22.994 (-22d 59' 38")
  Corners:
   337.871 (22h 31m 29s) -22.760 (-22d 45' 38")
   337.994 (22h 31m 59s) -23.010 (-23d 00' 37")
   339.494 (22h 37m 59s) -23.176 (-23d 10' 35")
   339.374 (22h 37m 30s) -22.943 (-22d 56' 35")
  ---------------------------------------------
The error box area is 1131 sq. arcmin, and its maximum
dimension is 1.6 deg (the minimum one is 13.6 arcmin).
The Sun distance was 64 deg.

This box may be improved.

The IPN localization is consistent with, but reduces the area of, the
Fermi GBM Final Real-time position (GCN Circ. 31955) and BALROG
(GCN 31950) localizations.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220426_T24589/IPN/

Swift ToO has been approved.

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


GRB_name: GRB220426A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31959
SUBJECT: Konus-Wind detection of GRB 220426A
DATE:    22/04/27 20:15:34 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The long GRB 220426A (BALROG localization: Biltzinger et al., GCN Circ. 
31950;
Swift/BAT-GUANO detection outside the coded FOV: Tohuvavohu et al.,
GCN Circ. 31954;
Fermi-GBM detection: Malacaria & Meegan, GCN Circ. 31955;
IPN localization: Kozyrev et al., GCN 31958)
triggered Konus-Wind (KW) at T0=24589.598 s UT (06:49:49.598).

The burst light curve shows a bright, double-peaked pulse
which starts at ~T0-0.5 s and has a total duration of ~11 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/GRB220426_T24589/

As observed by Konus-Wind, the burst had
a fluence of (9.2 Â± 0.2)x10^-5 erg/cm^2 and
a 64-ms peak energy flux, measured from T0 + 2.432 s,
of (2.9 Â± 0.2)x10^-5 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+13.312 s)
is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.29 (-0.07,+0.07),
the high energy photon index beta = -4.00 (-0.71,+0.32),
the peak energy Ep = 158 (-3,+4) keV,
chi2 = 112/97 dof.

The spectrum near the peak count rate (measured from T0+2.304 s
to T0+2.560 s) is best fit in the 20 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = 0.10 (-0.17,+0.21),
the high energy photon index beta = -5.6 (-4.3,+1.7),
the peak energy Ep = 227 (-15,+13) keV,
chi2 = 47/38 dof.

All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.


GRB_name: GRB220427A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31960
SUBJECT: GRB 220427A: Swift detection of a burst with an optical counterpart
DATE:    22/04/27 21:26:22 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

A. D'Ai (INAF-IASFPA), E. Ambrosi (INAF-IASFPA),
V. D'Elia (SSDC & INAF-OAR), C. Gronwall (PSU), J.D. Gropp (PSU),
J. A. Kennea (PSU), S. Laha (GSFC/UMBC), D. M. Palmer (LANL) and
A. Tohuvavohu (U Toronto) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 21:00:34 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 220427A (trigger=1104343).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 275.869, -56.253 which is 
   RA(J2000) = 18h 23m 29s
   Dec(J2000) = -56d 15' 09"
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 80 sec.  The peak count rate
was ~4000 counts/sec (15-350 keV), at ~10 sec after the trigger. 

The XRT began observing the field at 21:03:33.0 UT, 178.1 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 275.88860, -56.25508 which is
equivalent to:
   RA(J2000)  = 18h 23m 33.26s
   Dec(J2000) = -56d 15' 18.3"
with an uncertainty of 3.5 arcseconds (radius, 90% containment). This
location is 39 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 (1.02 x
10^21 cm^-2, Willingale et al. 2013), with an excess column of 2.9
(+3.18/-2.73) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White 
filter  starting 181 seconds after the BAT trigger. There is a 
candidate afterglow in  the rapidly available 2.7'x2.7' sub-image at  
RA(J2000) = 18:23:33.32 = 275.88882    
DEC(J2000) = -56:15:18.3 = -56.25507    
with a 90%-confidence error radius of about 0.61 arc sec. 
This position is 1.4  arc sec. from the center of the XRT error
circle. The estimated magnitude is  17.23 with a 1-sigma error of
about 0.14. No correction has been made for the  expected extinction
corresponding to E(B-V) of 0.097. 

The original BAT Position Notice found an approximate coincidence
(~10 arcmin) with the position of IGR J18244-5622 (which in turn 
is coincident with the Sey2 galaxy IC 4709 at z=0.017). 
However, the position of the X-ray and Optical counterpart 
excludes this source and galaxy, indicating that this is a new GRB. 

Burst Advocate for this burst is A. D'Ai (antonino.dai AT inaf.it). 
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: GRB220426A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31961
SUBJECT: GRB 220426A: Tiled Swift observations
DATE:    22/04/28 03:40:03 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
IPN GRB 220426A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00104

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 IPN 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: GRB220427A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31962
SUBJECT: GRB 220427A: Enhanced Swift-XRT position
DATE:    22/04/28 05:33:04 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 1603 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 220427A, 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 = 275.88811, -56.25541 which is equivalent
to:

RA (J2000): 18h 23m 33.15s
Dec (J2000): -56d 15' 19.5"

with an uncertainty of 2.5 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: GRB220427A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31963
SUBJECT: GRB 220427A: Swift-XRT refined Analysis
DATE:    22/04/28 07:12:52 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester), J.P. Osborne
(U. Leicester), M.G. Bernardini (INAF-OAB), E. Ambrosi (INAF-IASFPA) ,
M. Capalbi (INAF-IASFPA), J. D. Gropp (PSU), J.A. Kennea (PSU), A.
Tohuvavohu (U. Toronto) and A. D'Ai report on behalf of the Swift-XRT
team:

We have analysed 6.1 ks of XRT data for GRB 220427A (D'Ai et al. GCN
Circ. 31960), from 162 s to 30.4 ks after the  BAT trigger. The data
comprise 37 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. 31962).

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.05 (+0.05, -0.04).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.01 (+/-0.15). The
best-fitting absorption column is  1.6 (+0.5, -0.4) x 10^21 cm^-2, in
excess of the Galactic value of 1.0 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 3.4 x 10^-11 (4.5 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.6 (+0.5, -0.4) x 10^21 cm^-2
Galactic foreground: 1.0 x 10^21 cm^-2
Excess significance: 2.1 sigma
Photon index:      2.01 (+/-0.15)

If the light curve continues to decay with a power-law decay index of
1.05, the count rate at T+24 hours will be 6.1 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.1 x
10^-13 (2.8 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/01104343.

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


GRB_name: GRB220427A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31964
SUBJECT: Konus-Wind detection of GRB 220427A
DATE:    22/04/28 14:20:52 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The long GRB 220427A (Swift detection: D'Ai et al., GCN Circ. 31960)
triggered Konus-Wind (KW) at T0=75645.009 s UT (21:00:45.009).

The burst light curve shows a single pulse,
which starts at ~T0-3 s and has a total duration of ~15 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/GRB220427_T75645/

As observed by Konus-Wind, the burst had
a fluence of (1.0 Â± 0.3)x10^-5 erg/cm^2 and
a 64-ms peak energy flux, measured from T0 + 0.256 s,
of (2.5 Â± 0.7)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).

A time-averaged spectrum of the burst (measured from T0 to T0+8.448 s)
is well fit in the 20 keV - 15 MeV range
by a power law with exponential cutoff (CPL) model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -1.04(-0.30,+0.43) and Ep = 503(-204,+757) keV (chi2 = 77/97 dof).
A fit to this spectrum by the Band GRB function is poorly constrained,
it results in the best fit values of alpha~-0.6, Ep~260 keV, and
the high energy photon index beta ~ -2.0 (chi2 = 77/96 dof).

All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.


GRB_name: GRB220423A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31965
SUBJECT: GRB 220423A: Detection by VZLUSAT-2
DATE:    22/04/28 16:36:12 GMT
FROM:    Jakub Ripa at Masaryk University  <ripa.jakub@mail.muni.cz>

J. Ripa (Masaryk U.), A. Pal (Konkoly Observatory), M. Ohno (Hiroshima 
U.),  N. Werner  (Masaryk U.),  L. Meszaros (Konkoly Observatory), H. 
Takahashi (Hiroshima U.), B. Csak (Konkoly Observatory), M. Topinka, F. 
Munz, F. Hroch (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.

A long-duration GRB 220423A (AGILE/MCAL detection: Ursi et al., GCN 
Circ. 31938, Happy Birthday to AGILE!; Swift/BAT detection: Raman et 
al., GCN Circ. 31943; CALET/CGMB detection: trig. #1334758343; 
INTEGRAL/SPI-ACS detection: trig. #9870; KONUS-Wind detection: trig. 
time 2022-04-23 14:14:07.818 UT) was detected by both GRB detector units 
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 28 sigma detection significance was confirmed at each detector at 
2022-04-23 14:14:14 UTC. The GRB has the T90 duration of 37 s.

The light curve obtained by VZLUSAT-2 is available here:
https://vzlusat2.konkoly.hu/static/share/GRB220423A_GCN_VZLUSAT2.pdf

GRB detectors on VZLUSAT-2 are a demonstration payload for a future 
CubeSats 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: GRB220426A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31966
SUBJECT: GRB 220426A: Swift-XRT and UVOT observations
DATE:    22/04/28 17:31:31 GMT
FROM:    Valerio D'Elia at ASDC  <valerio.delia@ssdc.asi.it>

V. Dâ€™Elia (ASI-SSDC & INAF-OAR) and M. H. Siegel (PSU)
report on behalf of the Swift team:

Swift has performed follow-up observations of the Fermi/GBM-detected burst GRB 220426A (GCN Circ. 31950, 31955), which was also detected by Swift/BAT-GUANO (GCN Circ. 31954), Konus-Wind (GCN Circ. 31959), INTEGRAL/SPI-ACS, and HEND/Mars-Odyssey (GCN Circ. 31958).

The XRT observations consist of three tiles of 1 ks each, to cover the GRB error region. The data were acquired between 45 and 47 hours after the burst and are entirely in PC mode.

One bright, uncatalogued X-ray source has been detected:

Source 1:
  RA (J2000): 22h 32m 34.33s
  Dec (J2000): -22Â° 57â€² 01.0â€³
  Error: 3.7 arcsec (radius, 90% conf.)
  Count-rate: (1.4 +/- 0.5)e-2 ct s^-1
  Distance: 3.2 arcmin from the IPN position
  Flux: (4.1 +/- 1.4)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Nevertheless, we note that at the XRT position the RASS PSPC 3 sigma upper limit is 0.05 cts/s (XRT equivalent count-rate).

The UVOT took images of 616s each on the three XRT tiles with the white filter 160-170 ks after the trigger. We identify one source at 1.9â€ from the XRT coordinates of Source 1,  with a white magnitude of 18.01.

The UVOT position is:
   RA  (J2000) =  22:32:34.39 = 338.14330 (deg.)
   Dec (J2000) = -22:57:02.7  =  22.95074 (deg.)

with an estimated uncertainty of 0.5 arc sec. (radius, 90% confidence).

However, we note that this is a known source in the DSS and is therefore unlikely to be the afterglow. No other sources are detected to a limiting magnitude in the white filter of 20.8.

More Swift observations are planned in the next days to assess for variability

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/xrt_products/TILED_GRB00104/<https://eur02.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.swift.ac.uk%2Fxrt_products%2FTILED_GRB00104%2F&data=05%7C01%7Cvalerio.delia%40ssdc.asi.it%7Cbbf1b046abbf47f102b008da29348927%7Ccbfc58d4e60f468d8fe490676de085f7%7C0%7C0%7C637867602862749464%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=rivAVi0hBq7OV9vDQ4K1Xb1mbfcuxK9etLjffE3p1UI%3D&reserved=0>.

This circular is an official product of the Swift team.


GRB_name: GRB220427A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31967
SUBJECT: GRB 220427A: VLT/X-shooter photometry
DATE:    22/04/29 10:10:21 GMT
FROM:    Antonio de Ugarte Postigo at OCA  <deugarte@oca.eu>

A. de Ugarte Postigo (Artemis/OCA), H. Fausey (George Washington
University), D. A. Kann (HETH/IAA-CSIC), D. B. Malesani (Radboud
Univ. and DAWN/NBI), P. Jakobsson (U. of Iceland), A. Saccardi
(GEPI, Observatoire de Paris) and B. Schneider (CEA Paris-Saclay),
report on behalf of the Stargate Consortium:

We observed the field of GRB 220427A (D'Ai et al., GCN 31960)
using the ESO VLT UT3 (Melipal) equipped with the X-shooter
spectrograph. In images taken with the acquisition camera 7.9 hr
after the GRB we measure for the optical afterglow the following
AB magnitudes (calibrated against 2 field stars from the SkyMapper
catalogue):

g' = 22.40 +/- 0.09 mag
r' = 22.04 +/- 0.08 mag
z' = 20.81 +/- 0.08 mag

No useful spectroscopy could be secured.

We acknowledge excellent support from the ESO observing staff in
Paranal, in particular Jonathan Smoker and Rob van Holstein.


GRB_name: GRB220427A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31968
SUBJECT: GRB 220427A: Swift-BAT refined analysis
DATE:    22/04/29 13:45:22 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

M. Stamatikos (OSU) S. D. Barthelmy (GSFC),
A. D'Ai (INAF-IASFPA), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), A. Y. Lien (U Tampa),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Parsotan (GSFC/UMBC), T. Sakamoto (AGU)
(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 220427A (trigger #1104343)
(D'Ai et al., GCN Circ. 31960).  The BAT ground-calculated position is
RA, Dec = 275.922, -56.257 deg which is
   RA(J2000)  =  18h 23m 41.2s
   Dec(J2000) = -56d 15' 23.7"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 62%.

The mask-weighted light curve shows a single-peaked structure that
starts at ~T+3 s and peaks at ~T+8 s, and followed by a long tail
emission that ends at ~T+70 s. T90 (15-350 keV) is 57.2 +- 12.2 sec
(estimated error including systematics).

The time-averaged spectrum from T+3.09 to T+68.06 sec is best fit
by a simple power-law model.  The power law index of the time-averaged
spectrum is 1.23 +- 0.13.  The fluence in the 15-150 keV band is
2.1 +- 0.2 x 10^-6 erg/cm2. The 1-sec peak photon flux measured from
T+7.83 sec in the 15-150 keV band is 3.0 +- 0.3 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/1104343/BA/


GRB_name: GRB220430A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31972
SUBJECT: GRB 220430A: Swift detection of a burst or Swift J0630.4+0932
DATE:    22/04/30 14:22:26 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

E. Ambrosi (INAF-IASFPA), A. D'Ai (INAF-IASFPA),
V. D'Elia (SSDC & INAF-OAR), C. Gronwall (PSU), J.D. Gropp (PSU),
J. A. Kennea (PSU), A. Y. Lien (U Tampa), 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 13:53:15 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 220430A (trigger=1104692).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 97.611, +9.510 which is 
   RA(J2000) = 06h 30m 27s
   Dec(J2000) = +09d 30' 36"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve appears to show a
double-peaked structure with the second peak larger, and a total
duration of about 70 sec. The peak count rate was ~35000 counts/sec
(15-350 keV), at ~38 sec after the trigger. 

However, near the time of the GRB the Sun also produced an X-class 
solar flare which may be the cause of some or all of the apparent
lightcurve activity.  The GRB emission will be independently
determined once the mask-tagged BAT data has been received. 

The XRT began observing the field at 13:54:07.7 UT, 51.7 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source with an enhanced position: RA, Dec 97.61267,
9.54730 which is equivalent to:
   RA(J2000)  = 06h 30m 27.04s
   Dec(J2000) = +09d 32' 50.3"
with an uncertainty of 1.9 arcseconds (radius, 90% containment). This
location is 134 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 (6.47 x
10^21 cm^-2, Willingale et al. 2013), with an excess column of 1.1
(+0.75/-0.59) x 10^22 cm^-2 (90% confidence). 

The initial flux in the 0.1 s image was 4.31e-08 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 60 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 large, but uncertain, extinction expected. 

Although this looks like a GRB both in terms of its lightcurve and
the presence of strong flux above 100 keV, its location near the
Galactic plane (lon=202.05, lat=-0.26) raises the possibility of it
being a Galactic transient.  In addition, as noted above, the
apparent lightcurve may be due to solar activity. If further 
analysis shows that it is a Galactic transient, we will use the 
name Swift J0630.4+0932. 

Burst Advocate for this burst is E. Ambrosi (elena.ambrosi AT inaf.it). 
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: GRB220430A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31973
SUBJECT: GRB 220430A: Enhanced Swift-XRT position
DATE:    22/04/30 18:35:16 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 1120 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 220430A, 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 = 97.61218, +9.54754 which is equivalent
to:

RA (J2000): 06h 30m 26.92s
Dec (J2000): +09d 32' 51.1"

with an uncertainty of 2.0 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: GRB220430A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31974
SUBJECT: GRB 220430A: MeerLICHT optical upper limits
DATE:    22/04/30 19:04:51 GMT
FROM:    Paul Groot at Radboud University Nijmegen  <p.groot@astro.ru.nl>

P.J. Groot (Radboud/UCT/SAAO), S.de Wet (UCT), D.B. Malesani
(Radboud, DAWN/NBI), A.J. Levan (Radboud), P.M. Vreeswijk (Radboud),
report on behalf of the MeerLICHT consortium:

GRB220430A (Ambrosi et al., GCN 31972) triggered automatic observations
with the 0.6m wide-field MeerLICHT telescope, located at Sutherland,
South Africa. Observations started at 2022-04-30, 17:10:19 UT in a
series of 60s integrations in an alternating sequence of the
u,g,q,r,i,z bands. Observations were stopped after 2022-04-30,
17:27:48 UT due to the visibility of the source location. 

A preliminary analysis of the u, q and i-band images shows no new
optical transient in these bands within the Swift-BAT error circle,
including the position of the new X-ray source detected in the Swift-XRT
observations. 

Five-sigma limiting magnitudes for an optical transient located at the
Swift-XRT position are: 
u > 19.0 at 17:11:46 UT, 
q > 20.4 at 17:13:14 UT, 
i > 18.6 at 17:20:32 UT. 

Further analysis is ongoing

MeerLICHT is built and run by a consortium consisting of Radboud
University, the University of Cape Town, the South African Astronomical
Observatory, the University of Oxford, the University of Manchester
and the University of Amsterdam.


GRB_name: GRB220430A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31975
SUBJECT: GRB 220430A: AGILE detection
DATE:    22/04/30 19:06:05 GMT
FROM:    Alessandro Ursi at INAF/IAPS  <alessandro.ursi@gmail.com>

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

The AGILE satellite detected the GRB 220430A at T0 = 2022-04-30 13:53:45
(UTC), reported by Swift (GCNs #31972 and #31973).

The burst is clearly visible in the AGILE scientific ratemeters of the
SuperAGILE detector (SA; 20-60 keV) and in all the five panels of the
AntiCoincidence system (AC Top, 50-200 keV; AC Lat, 80-200 keV). The event
lasted about 25 s and it released a total number of 2685 counts in the SA
detector (above a background rate of 100 Hz), 25765 counts in the MCAL
detector (above a background rate of 1070 Hz), and 67565 counts in the AC
detector (above a background rate of 2710 Hz). The AGILE ratemeter light
curves can be found at
http://www.agilescienceapp.it/notices/GRB220430A_AGILE_RM.png .

As pointed out in GCN #31972, we notice that this event took place at the
end of an intense X-class solar flare, clearly detected by all the AGILE
scientific ratemeters. A more extended light curve can be found at
http://www.agilescienceapp.it/notices/GRB220430A_AGILE_RM_all.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: GRB220430A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31976
SUBJECT: GRB 220430A: Mondy and AbAO optical upper limits
DATE:    22/04/30 21:25:52 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

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

We observed the field of Swift GRB 220430A (Ambrosi et al., GCN 31972) 
also detected by AGILE (Ursi  et al., GCN 31975) with AZT-33 telescope 
of Mondy observatory starting on April, 30  (UT) 14:20:53 and AS-32 
telescope of Abastumani observatory starting on April, 30  (UT) 
16:59:12.   We do not detect any sources in the enhanced position of 
Swift-XRT (Osborne et al., GCN 31973) consistent with the observations 
of Swit/UVOT (Ambrosi et al., GCN 31972) and MeerLICHT (Groot et al., 
GCN 31974).
Preliminary photometry of the  combined images is following

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

2022-04-30  14:20:53 0.01953    1*60   R      n/d    n/d    19.5
2022-04-30  14:20:53 0.02613   20*60   R      n/d    n/d    20.5
2022-04-30  16:59:12 0.14962   59*60   R      n/d    n/d    21.0

The photometry is based on nearby USNO-B1.0 stars, R2 magnitude
USNO-B1.0_id R2
0995-0113632 16.50
0995-0113723 15.94


GRB_name: GRB220430A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31977
SUBJECT: GRB 220430A: GRANDMA observations
DATE:    22/05/01 00:24:17 GMT
FROM:    Alain Klotz at IRAP-CNRS-OMP  <Alain.Klotz@free.fr>

D. Dornic (CPPM), A. Klotz (CNRS-OMP-IRAP), A. Sabahaddin (ShaO),
T. Midavaine (KNC), V. Rupchandani (AUS), P. A. Duverne (IJCLAB),
Y. Rajabov (UBAI), X. Song (BJP), X. F. Wang (THU/BJP), J. Zhu (BJP),
L. Wang,  X. Zeng, A. Iskandar (XAO), P. Thierry (AGORA),
A. Kaeouach (Tanger), Z. Benkhaldoun (OUCA),
S. Antier, A. de Ugarte Postigo (CNRS-OCA-ARTEMIS)
report on behalf of GRANDMA collaboration:

The GRANDMA telescope network responded to the alert of GRB 220430A
(Ambrosi et al. GCN 31972, Osborne et al., GCN 31973,
Groot et al., GCN 31974, Ursi  et al., GCN 31975,
Pozanenko et al. GCN 31976). The first observations
started 34 min after the SWIFT BAT trigger time.

We did not detect any optical transient within the XRT error box
during the first 2.9 hours. We report our 3-sigma upper limits.
Magnitudes are given in the AB system.

T-T0 (hr)| MJD       | Obser.   |Exposure| Filter| Upp.Lim. (AB)
0.56111  |59699.60204| SNOVA      | 4x300s | Clear | 19.0
2.59194  |59699.68666| Makes-T60| 10x120s| Clear | 19.5
6.24347  |59699.83880| HAO      | 20x120s| L     | 20.6
6.33472  |59699.84260| MOSS     | 30x60s | Clear | 21.0

The images have been calibrated with SDSS DR7.
T-T0 is the started date.

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: GRB220430A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31978
SUBJECT: Swift GRB 220430A: Global MASTER-Net observations report 
DATE:    22/05/01 03:04:33 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-OAGH robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) was pointed to the Swift GRB 220430A ( E. Ambrosi et al., GCN 31972) errorbox  46599 sec after notice time and 46878 sec after trigger time at 2022-05-01 02:54:34 UT, with upper limit up to  15.0 mag. Observations started at twilight.  The observations began at zenith distance = 56 deg. The sun  altitude  is -12.3 deg. 

The galactic latitude b =  0 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=1959132

We obtain a following upper limits.  

Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

   46968 |         MASTER-OAGH |   C |   180 | 15.0 |        
   46968 |         MASTER-OAGH |   C |   180 | 14.9 |        
Filter C is a clear (unfiltred) band. 


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


GRB_name: GRB220430A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31979
SUBJECT: GRB 220430A: Swift-XRT refined Analysis
DATE:    22/05/01 03:34:28 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester), M. Capalbi
(INAF-IASFPA), M. Perri (SSDC & INAF-OAR), J.A. Kennea (PSU), A.
Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), K.L. Page (U. Leicester)
and E. Ambrosi report on behalf of the Swift-XRT team:

We have analysed 7.6 ks of XRT data for GRB 220430A (Ambrosi et al. GCN
Circ. 31972), from 39 s to 39.2 ks after the  BAT trigger. The data
comprise 539 s in Windowed Timing (WT) mode (the first 11 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 Osborne et
al. (GCN Circ. 31973).

The late-time light curve (from T0+4.2 ks) can be modelled with a
power-law decay with a decay index of alpha=1.35 (+/-0.09).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.65 (+/-0.05). The
best-fitting absorption column is  1.05 (+0.07, -0.06) x 10^22 cm^-2,
in excess of the Galactic value of 6.5 x 10^21 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.85 (+0.17, -0.16)
and a best-fitting absorption column of 1.03 (+0.19, -0.17) x 10^22
cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 5.3 x 10^-11 (8.9 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.03 (+0.19, -0.17) x 10^22 cm^-2
Galactic foreground: 6.5 x 10^21 cm^-2
Excess significance: 3.8 sigma
Photon index:      1.85 (+0.17, -0.16)

If the light curve continues to decay with a power-law decay index of
1.35, 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 8.0 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/01104692.

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


GRB_name: GRB220430A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31980
SUBJECT: GRB 220430A: CAHA 2.2m telescope optical limit
DATE:    22/05/01 09:53:15 GMT
FROM:    Youdong HU at IAA-CSIC  <huyoudong072@hotmail.com>

Y.-D. Hu, T.-R. Sun, M. D. Caballero-Garcia, R. Sanchez-Ramirez, I. Perez-Garcia and A. J. Castro-Tirado (IAA-CSIC), R. Minguez and I. Vico (CAHA) on behalf of a larger collaboration, report:

Following the detection of GRB 220430A by Swift (Ambrosi et al. GCNC 31972) and AGILE (Ursi et al. GCNC 31975), we triggered the 2.2m CAHA telescope (+ CAFOS) at the Calar Alto Observatory (Almeria, Spain). Images were gathered after the twilight starting on Apr. 30 20:15 UT (i.e. 6.4 hrs post trigger) in Sloan-gri at high airmass. On the co-added Sloan-i band image (8x60s), no optical transient down to 22.1 mag is detected at the X-ray afterglow candidate position reported by Swift/XRT (Ambrosi et al. GCNC 31972, J.P. Osborne et al. GCNC 31973). This non-detection is consistent with the report from Groot et al. (GCNC 31974), Pankov et al.(GCNC 31976), Dornic et al. (GCNC 31977) and V. Lipunov et al.(GCNC 31978).

We thank the staff at Calar Alto observatory for their excellent support.


GRB_name: GRB220430A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31981
SUBJECT: GRB 220430A: Swift-BAT refined analysis
DATE:    22/05/01 15:16:28 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

S. D. Barthelmy (GSFC), E. Ambrosi (INAF-IASFPA),
H. A. Krimm (NSF), 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-204 to T+843 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 220430A (trigger #1104692)
(Ambrosi et al., GCN Circ. 31972).  The BAT ground-calculated position is
RA, Dec = 97.616, 9.547 deg which is
   RA(J2000)  =  06h 30m 27.9s
   Dec(J2000) = +09d 32' 50.1"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve shows two major pulse emissions. The first
one starts at ~T-7 s, peaks at ~T+20 s, and ends at ~T+30 s. It is
followed by another larger pulse with several peaks. The largest peak
occurs at ~T+42 s. The burst emission ends at ~T+100 s. T90 (15-350 keV)
is 43.10 +- 0.57 sec (estimated error including systematics).

The time-averaged spectrum from T-6.53 to T+94.36 sec is best fit by
a simple power-law model.  The power law index of the time-averaged
spectrum is 1.24 +- 0.02.  The fluence in the 15-150 keV band is
4.4 +- 0.05 x 10^-5 erg/cm2. The 1-sec peak photon flux measured from
T+42.00 sec in the 15-150 keV band is 29.6 +- 0.6 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/1104692/BA/


GRB_name: GRB220501A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31982
SUBJECT: GRB 220501A: Swift detection of a burst
DATE:    22/05/01 20:00:43 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

A. D'Ai (INAF-IASFPA), E. Ambrosi (INAF-IASFPA),
V. D'Elia (SSDC & INAF-OAR), C. Gronwall (PSU), A. Y. Lien (U Tampa),
K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of
the Neil Gehrels Swift Observatory Team:

At 19:51:51 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 220501A (trigger=1104842).  Swift did not slew to the
burst location due to an observing constraint. 
The BAT on-board calculated location is 
RA, Dec 85.577, +14.033 which is 
   RA(J2000) = 05h 42m 18s
   Dec(J2000) = +14d 02' 00"
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 60 sec.  The peak count rate
was ~2500 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to a Sun observing constraint, Swift cannot slew to the BAT
position until 07:38 UT on 2022 August 04. There will thus be no XRT or
UVOT data for this trigger before this time. 

Burst Advocate for this burst is A. D'Ai (antonino.dai AT inaf.it). 
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: GRB220501A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31983
SUBJECT: GRB 220501A: Fermi GBM Final Real-time Localization
DATE:    22/05/01 20:02:07 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 19:51:50 UT on 1 May 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220501A (trigger 673127515.736396 / 220501828).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 71.8, Dec = 11.5 (J2000 degrees, equivalent to J2000 04h 47m, 11d 30'), with a statistical uncertainty of 6.3 degrees.

The angle from the Fermi LAT boresight is 89.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220501828/quicklook/glg_skymap_all_bn220501828.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220501828/quicklook/glg_healpix_all_bn220501828.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220501828/quicklook/glg_lc_medres34_bn220501828.gif


GRB_name: GRB220501A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31984
SUBJECT: GRB 220501A: GRANDMA/TJML Optical Observations
DATE:    22/05/01 22:56:07 GMT
FROM:    Alexander Kann at IAA-CSIC  <kann@iaa.es>

A. Klotz (CNRS-OMP-IRAP), A. de Ugarte Postigo, S. Antier (both 
CNRS-OCA-ARTEMIS), D. Dornic (CPPM), A. Sabahaddin (ShaO),T. Midavaine 
(KNC), V. Rupchandani (AUS), P. A. Duverne (IJCLAB), Y. Rajabov (UBAI), 
X. Song (BJP), X. F. Wang (THU/BJP), J. Zhu (BJP), L. Wang,  X. Zeng, A. 
Iskandar (XAO), and D. A. Kann (IAA-CSIC) report on behalf of the 
GRANDMA collaboration:

We observed the BAT error circle of GRB 220501A (D'Ai et al., GCN 31982; 
Fermi GBM Team, GCN 31983) with the TJML 11" Celestron telescope 
installed at Guitalens observatory. We recorded a stack of 8 x 60 s 
unfiltered images in the range from 28.8 to 38.9 minutes after the 
trigger.

We did not detect any optical counterpart of GRB 220501A in the BAT 
error circle to a limiting magnitude r(AB) > 16.0 mag. Photometry was 
calibrated against the Pan-STARRS catalog.

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: GRB220430A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31987
SUBJECT: GRB 220430A: AstroSat CZTI detection
DATE:    22/05/02 07:40:42 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

R. Gopalakrishnan (IUCAA), V. Prasad (IUCAA), G. Waratkar (IITB), A. 
Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (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 detection of a long GRB 220430A which was 
also reported by Swift (Ambrosi et al., GCN 31972; Osborne et al., GCN 
31973; Barthelmy et al., GCN 31981), and AGILE (Ursi et al., GCN 31975).

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 
2022-04-30 13:53:58.50 UT. The measured peak count rate associated with 
the burst is 892 (+60, -62) counts/s above the background in the 
combined data of all the quadrants, with a total of 11896 (+669, -639) 
counts. The local mean background count rate was 484 (+2, -2) counts/s. 
Using cumulative rates, we measure a T90 of  40 (+4, -2) s.

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 2022-04-30 13:53:58.52 UT. The 
measured peak count rate is 3131 (+109, -98) counts/s above the 
background in the combined Veto data of four quadrants, with a total of 
48203 (+1134, -1252) counts. The local mean background count rate was 
1614 (+3, -5) counts/s. We measure a T90 of 41 (+1, -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 [1]. CZTI is built by a TIFR-led 
consortium of institutes across India, including VSSC, ISAC, 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: GRB220501A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31988
SUBJECT: GRB 220501A: Fermi GBM observation
DATE:    22/05/02 13:53:38 GMT
FROM:    Oliver J Roberts at USRA/NASA  <oliver.roberts@nasa.gov>

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

"At 19:51:50.74 UT on 01 May 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220501A (trigger 673127515 / 220501828), which
was also detected by Swift/BAT (A. D'Ai et al. 2022, GCN 31982). The
Fermi GBM Final Real-time Localization (GCN 31983) is consistent with the
Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 94 degrees.

The GBM light curve shows a FRED-like burst
with a duration (T90) of about 51 s (50-300 keV).
The time-averaged spectrum from T0-3.6 s to T0+47.6 s is
best fit by a power law function with an exponential
high-energy cutoff. The power law index is -0.49 +/- 0.18 and
the cutoff energy, parameterized as Epeak, is 114 +/- 11 keV

The event fluence (10-1000 keV) in this time interval is
(3.53 +/- 0.24)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+2.0 s in the 10-1000 keV band
is 2.5 +/- 0.2 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: GRB220501A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31990
SUBJECT: GRB 220501A: BOOTES-1 optical upper limit
DATE:    22/05/02 18:47:52 GMT
FROM:    Youdong HU at IAA-CSIC  <huyoudong072@hotmail.com>

Y.-D. Hu, E. Fernandez-Garcia, T.-R. Sun, A. J. Castro-Tirado, M. D. Caballero-Garcia, R. Sanchez-Ramirez, I. Perez-Garcia (IAA-CSIC),  C. Perez del Pulgar,  A. Castellon, I. Carrasco, A. Reina (Univ. de Malaga) and F. Rendon (IAA-CSIC and INTA-CEDEA) on behalf of a larger collaboration, report:

Following the detection of GRB 220501A by Swift (D'Ai et al., GCNC 31982) and Fermi (Fermi GBM team, GCNC 31983, Roberts et al. GCNC 31988), the 0.3m BOOTES-1B robotic telescope in Mazagon (Huelva), southern Spain, automatically responded to this burst on May 1 at 20:14 UT (~22.3 min after trigger), right after the twilight and at high airmass. In the co-added frame (38 x 10 s, clear filter), no source is detected within the BAT error position (D'Ai et al., GCNC 31982) down to 17.5 mag, which is consistent with the non-detection reported by Klotz et al. (GCNC 31984).

We thank the staff at INTA-CEDEA for their excellent support.


GRB_name: GRB220427A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31991
SUBJECT: GRB 220427A: GRANDMA Early Optical Afterglow Detection
DATE:    22/05/02 19:34:07 GMT
FROM:    Alexander Kann at IAA-CSIC  <kann@iaa.es>

A. Klotz (CNRS-OMP-IRAP), M. Blazek (FZU), N. Christensen (OCA/Artemis), 
D. Datashvili (AbAO), P. A. Duverne (IJCLAB), F. Z. Guo (THU), N. 
Kochiashvili (AbAO), M. Lamoureux (UCLouvain), N. Leroy (IJCLAB), T. 
Sadibekova (AIM/CEA-UPS), P. Thierry (AGORA), A. Simon (Kyiv Univ), L. 
Eymar, S. Antier, M. Boer, A. de Ugarte Postigo (all CNRS-OCA-ARTEMIS), 
D. A. Kann (IAA-CSIC), A. Iskandar (XAO), A. Baransky (Kyiv Univ),
N. Sasaki (NEPA/UEA), W. Corradi (LNA), I. Tosta e Melo (INFN-LNS), J. 
P. Vignes (KNC), V. Godunova (IC ICAMER) report on behalf of GRANDMA 
collaboration:

The GRANDMA telescope network responded promptly to the alert of GRB 
220427A (A. D'Ai et al. GCN 31960, M. R. Goad et al. GCN 31962, A. P. 
Beardmore et al. GCN 31963, M. Stamatikos et al. GCN 31968).

The first observations with TAROT La Reunion started 2.35 min after the 
Swift/BAT trigger time, and were followed by observations with the Les 
Makes T60. Later observations were obtained by the CDK40 0.4m telescope 
that is part of the Kilonova-Cather citizen science programme. The light 
curve peaked around 4.5 min after the burst and then decayed steadily 
with a decay slope of alpha ~ 1.3, where F ~ t^-alpha.

The following table displays part of our photometry with magnitudes 
given in the AB system and calibrated with respect to field stars from 
the SkyMapper catalogue, using the MUPHOTEN pipeline (Duverne et al. 
2021).


T-T0 (hr)| MJD   | Obser.     |Exposure| Filter| Mag +/- err (AB)
_________________________________________________________________
0.04 |59696.878276| TRE       |     60s| Clear | 15.7 +/- 0.2
1.38 |59696.932836| Makes-T60 | 15x120s| Clear | 20.1 +/- 0.1
1.65 |59696.944294| Makes-T60 | 15x120s| Clear | 20.4 +/- 0.2
11.37|59697.3491  | KNC-CDK400| 10x300s| R     | > 21.0

T-T0 is the mid-time of observations related to the BAT trigger time.

These detections are consistent with the previous report of detections 
by the VLT (A. de Ugarte Postigo et al. GCN 31967).

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: GRB220501A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31993
SUBJECT: GRB 220501A: Swift-BAT refined analysis
DATE:    22/05/02 22:12:43 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

H. A. Krimm (NSF),S. D. Barthelmy (GSFC),
A. D'Ai (INAF-IASFPA), 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+816 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 220501A (trigger #1104842)
(D'Ai et al., GCN Circ. 31982).  The BAT ground-calculated position is
RA, Dec = 85.583, 14.010 deg which is
   RA(J2000)  =  05h 42m 20.0s
   Dec(J2000) = +14d 00' 36.5"
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 92%.

The mask-weighted light curve shows a FRED-like pulse that starts
at ~T-1 s and peaks at ~T+5 s. It is followed by a second weak pulse
at ~T+200 s. T90 (15-350 keV) is 202.24 +- 20.60 sec (estimated error
including systematics).

The time-averaged spectrum from T-1.21 to T+224.20 sec is best fit
by a power law with an exponential cutoff.  This fit gives a photon
index 0.64 +- 0.62, and Epeak of 72.3 +- 28.6 keV (chi squared 44.65
for 56 d.o.f.).  For this model the total fluence in the 15-150 keV
band is 2.2 +- 0.2 x 10^-6 erg/cm2 and the 1-sec peak flux measured
from T+4.28 sec in the 15-150 keV band is 1.2 +- 0.2 ph/cm2/sec.
 A fit to a simple power law gives a photon index of 1.54 +- 0.13
(chi squared 52.35 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/1104842/BA/


GRB_name: GRB220427A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31995
SUBJECT: GRB 220427A: LCO Optical Observations
DATE:    22/05/03 18:41:20 GMT
FROM:    Robert Strausbaugh at U. of the Virgin Islands  <robert.strausbaugh@uvi.edu>

R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (College of Marin) report on behalf of a larger collaboration:

We observed Swift GRB220427A (D'Ai et al. GCN 31960) with the LCO 1-m Sinistro instrument at the South African Astronomical Observatory site, on April 27, from 22:57 to 23:24 UT (corresponding to 1.95 to 2.40 hours from the GRB trigger time) with the Bessel R and I filters.

We performed a series of 3x300s exposures in I and R bands. We detect an optical counterpart at the location of the Swift optical counterpart that is consistent with other optical detections (Ugarte Postigo, et al., GCN 31967; Klotz, et al., GCN 31991). The following magnitudes are calculated using the USNO-B.1 catalog as reference:

R=20.35+/-0.12
I=20.15+/-0.30

These magnitudes are not corrected for galactic extinction.

R.S. is funded by NSF AST grant #1831682


GRB_name: GRB220423A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31996
SUBJECT: IPN triangulation of GRB 220423A
DATE:    22/05/04 20:35:15 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 team,

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,

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

and

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

The long-duration GRB 220423A
(AGILE detection: Ursi et al., GCN Circ. 31938;
Swift/BAT-GUANO detection: Raman et al., GCN Circ. 31943;
VZLUSAT-2 detection: Ripa et al., GCN Circ. 31965)
was detected by CALET (CGBM), INTEGRAL (SPI-ACS), Konus-Wind,
Swift (BAT), AGILE (MCAL, SA, AC), BepiColombo (MGNS), and VZLUSAT-2
at about 51251 s UT (14:14:11).
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:
    20.784 (01h 23m 08s) +22.205 (+22d 12' 18")
  Corners:
    19.674 (01h 18m 42s) +21.578 (+21d 34' 40")
    21.136 (01h 24m 33s) +22.784 (+22d 47' 02")
    21.890 (01h 27m 34s) +22.712 (+22d 42' 43")
    20.459 (01h 21m 50s) +21.615 (+21d 36' 56")
  ---------------------------------------------
The error box area is 3047 sq. arcmin, and its maximum
dimension is 2.3 deg (the minimum one is 29 arcmin).
The Sun distance was 13 deg.

This box may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220423_T51247/IPN

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


GRB_name: GRB220430A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31997
SUBJECT: GRB 220430A: GIT optical upper limits
DATE:    22/05/05 00:54:08 GMT
FROM:    Varun Bhalerao at Indian Inst of Tech  <varunb@iitb.ac.in>

V. Swain (IITB), H. Kumar (IITB), K. Angail (IAO), V. Bhalerao (IITB), G. C. Anupama (IIA), S. Barway (IIA) report on behalf of the GIT team:

We observed GRB 220430A detected by Swift (Ambrosi et al. GCN #31972) and AGILE (Ursi et al. GCN #31975), with a 0.7m GROWTH-India Telescope (GIT). The observation started on 2022-04-30 at 14:23:56 UT, 30.65 min after the SWIFT BAT trigger. We obtained multiple 100-sec exposures in the r' and i' filters. The images were shallower than usual due to poor observing conditions. We did not detect any new source in our stacked image within the 2.0" circle around R.A.= 06h 30m 26.92s, Dec.= +09d 32' 51.1" (J.P. Osborne et al. GCN #31973). The obtained upper limits follow as:

-------------------------------------------------------------------
JD (mid) | T_mid-T0(hrs) | Exposure (sec) | Filter | Lim_mag (5-sigma) |
-------------------------------------------------------------------
2459700.10382 | 0.60 | 300 (stacked) | r' | > 19.26 | 
2459700.10763 | 0.69 | 300 (stacked) | i' | > 18.68 | 
-------------------------------------------------------------------

The upper limits are consistent with the Ambrosi et al., (GCN #31972), Groot et al. (GCN #31974), Pankov et al.(GCNC #31976), Dornic et al. (GCN #31977), V. Lipunov et al.(GCN #31978) and Y.-D. Hu et al. (GCN #31980). The magnitudes are calibrated against PanSTARRS DR1 (Chambers et al., 2016) and not corrected for Galactic extinction.

The GROWTH India Telescope (GIT) 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: GRB220430A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31998
SUBJECT: GRB 220430A: Nanshan/HMT optical upper limit
DATE:    22/05/06 04:52:43 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

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

We observed the field of GRB 220430A detected by Swift (Ambrosi et al., 
GCN 31972) and AGILE (Ursi et al., GCN 31975) using the HMT-0.5m 
telescope located at Nanshan, Xinjiang, China. Observations started at 
13:58:51 UT on 2022-04-30 (i.e., 5.6 min after the BAT trigger), and 
3x20, 3x40, 4x60, 12x90 s unfiltered frames were obtained.

No optical source is detected in our stacked image at the XRT position 
(Osborne et al., GCN 31973), down to a limiting magnitude of ~19.2, 
calibrated with the Gaia DR2 stars.


GRB_name: GRB220430A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  31999
SUBJECT: GRB 220430A: Nanshan/NEXT optical upper limit
DATE:    22/05/06 04:58:07 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

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

We observed the field of GRB 220430A detected by Swift (Ambrosi et al., 
GCN 31972) and AGILE (Ursi et al., GCN 31975) using the NEXT-0.6m 
telescope located at Nanshan, Xinjiang, China. Observations started at 
14:13:38 UT on 2022-04-30 (i.e., 20.39 min after the BAT trigger). We 
obtained 3x40, 6x60, 3x90, 6x200 s frames in the Sloan r-band and 
3x60,3x90,6x200 s frames in Sloan z-band.

No optical source is detected in our stacked image at the XRT enhanced 
position (Osborne et al., GCN 31973), with upper limits as follows

Tmid-T0 (hr) Filter   UpperLimit (3sigma)
    0.953           r         >20.7
    0.923           z         >19.0

calibrated with the nearby PanSTARRS field.


GRB_name: GRB220506A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32005
SUBJECT: GRB 220506A: Tiled Swift observations
DATE:    22/05/06 16:54:11 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
MAXI GRB 220506A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00105

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 MAXI 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: GRB220506A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32006
SUBJECT: GRB 220506A: Swift-XRT afterglow detection
DATE:    22/05/07 09:10:00 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift-XRT has performed follow-up observations of the MAXI-detected
burst GRB 220506A (Urabe et al. GCN Circ. 32001) in a series of
observations tiled on the sky. The total exposure time is 1.2 ks,
distributed over 6 tiles; the maximum exposure at a single sky location
was 463 s. The data were collected between T0+38.2 ks and T0+55.6 ks,
and are entirely in Photon Counting (PC) mode. 

An uncatalogued X-ray source is detected and is above the RASS 3-sigma
upper limit at this position, and is therefore likely the GRB
afterglow.  The position of this source is RA, Dec=239.7257, -26.4186
which is equivalent to:

RA (J2000): 15:58:54.18
Dec(J2000): -26:25:06.9

with an uncertainty of 7.2 arcsec (radius, 90% confidence).  This
position is 15.0 arcmin from the MAXI position.  We cannot determine at
the present time whether the source is fading.

The results of the XRT-team automatic analysis of the likely afterglow
are at https://www.swift.ac.uk/xrt_products/TILED_GRB00105/Source1.php.

The results of the full analysis of the tiled XRT observations are
available at https://www.swift.ac.uk/xrt_products/TILED_GRB00105.

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


GRB_name: GRB220506A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32008
SUBJECT: GRB 220506A: BOOTES-5/JGT optical upper limit
DATE:    22/05/07 16:44:31 GMT
FROM:    Youdong HU at IAA-CSIC  <huyoudong072@hotmail.com>

Y.-D. Hu, E. Fernandez-Garcia, I. Perez-Garcia, T.-R. Sun, A. J. Castro-Tirado, M.D. Caballero-Garcia, R. Sanchez-Ramirez (IAA-CSIC), D. Hiriart and W. H. Lee (UNAM), C. J. Perez del Pulgar and I. Carrasco (UMA), I. H. Park (SKKU) on behalf of a larger collaboration, report:

Following the detection of GRB 220506A by MAXI/GSC (Urabe et al. GCNC 32001) and Swift (Evans et al. GCNC 32005), the BOOTES-5/JGT 0.6m robotic telescope at Observatorio Astronomico Nacional in San Pedro Martir (Mexico) observed the GRB location starting on May 7, 10:36 UT (~1.2 days after trigger) at high airmass. In the co-added image (15 x 60 s exposures in the clear filter), no optical afterglow is detected within the Swift/XRT error region (Osborne et al. GCNC 32006) down to 19.0 mag.

We thank the staff at Observatorio Astronomico Nacional in San Pedro Martir for their excellent support.


GRB_name: GRB220507A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32009
SUBJECT: GRB 220507A: Fermi GBM Final Localization
DATE:    22/05/07 17:57:30 GMT
FROM:    Christian Malacaria at NASA-MSFC/USRA  <cmalacaria@usra.edu>

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

At 10:09:05.75 UT on 7 May 2022, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 220507A (trigger 673610950 / 220507423).

The on-ground calculated location, using the Fermi GBM trigger data, is 
RA = 222.1, Dec = 53.2 (J2000 degrees, equivalent to J2000 14h 48m, 53d 13'),
with a statistical uncertainty of 3.7 degrees.

The angle from the Fermi LAT boresight is 54 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220507423/quicklook/glg_skymap_all_bn220507423.png

The HEALPix FITS file, including the estimated localization systematic, can
be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220507423/quicklook/glg_healpix_all_bn220507423.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220507423/quicklook/glg_lc_medres34_bn220507423.gif


GRB_name: GRB220508A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32010
SUBJECT: GRB 220508A: Fermi GBM Final Real-time Localization
DATE:    22/05/08 22:43:05 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 22:32:49 UT on 8 May 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220508A (trigger 673741974.516028 / 220508939).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 344.4, Dec = -3.2 (J2000 degrees, equivalent to J2000 22h 57m, -3d 12'), with a statistical uncertainty of 3.0 degrees.

The angle from the Fermi LAT boresight is 69.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220508939/quicklook/glg_skymap_all_bn220508939.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220508939/quicklook/glg_healpix_all_bn220508939.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220508939/quicklook/glg_lc_medres34_bn220508939.gif


GRB_name: GRB220506A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32012
SUBJECT: GRB 220506A: GIT optical upper limit.
DATE:    22/05/09 19:01:11 GMT
FROM:    Harsh Kumar at Indian Inst of Tech,Bombay  <harshkosli13@gmail.com>

V. Swain (IITB), H. Kumar (IITB), K. Angail (IAO), V. Bhalerao (IITB), G.
C. Anupama (IIA), S. Barway (IIA) report on behalf of the GIT team:

We observed GRB 220506A detected by MAXI/GSC (Urabe et al. GCN #32001) and
Swift (Phil Evans et al. GCN #32005), with a 0.7m GROWTH-India Telescope
(GIT). The observation started at 19:08:47 UT on 2022-05-06, 12.68 hours
after the MAXI/GSC trigger. We obtained multiple 300-sec exposures in the
r' filter. We did not detect any new source in our stacked image within the
7.2 arcsec radius circle around R.A.= 15h 58m 54.18s, Dec.= -26d 25' 06.9"
(Phil Evans et al. GCN #32006). The obtained upper limit follows as:
----------------------------------------------------------------------------------
 JD (mid) | T_mid-T0(hrs) | Exposure (sec) | Filter | Lim_mag (5-sigma) |
----------------------------------------------------------------------------------
 2459706.327602595 | 13.39 | 7 x 300 (stacked) | r' | >20.38 |
----------------------------------------------------------------------------------

The magnitudes are calibrated against PanSTARRS DR1 (Chambers et al., 2016)
and not corrected for Galactic extinction.


The GROWTH India Telescope (GIT) 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: GRB220506A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32014
SUBJECT: GRB 220506A: MITSuME Akeno optical upper limits
DATE:    22/05/10 06:41:09 GMT
FROM:    Naohiro Ito at Tokyo Tech  <n.ito@hp.phys.titech.ac.jp>

N. Ito, M. Sasada, Y. Imai, K. L. Murata, M. Niwano, Y. Takamatsu, S.
Sato, M. Tateda, T. Hattori, R. Hosokawa, Y. Yatsu, and N. Kawai
(Tokyo Tech) report on behalf of the MITSuME collaboration:

We observed the field of GRB 220506A (Urabe et al. GCN Circular
#32001, Evans et al. GCN Circular #32005, Osborne et al. GCN Circular
#32006, Hu et al. GCN Circular #32008, Swain et al. GCN Circular
#32012) with the optical three color (g', Rc, and Ic) CCD cameras
attached to the MITSuME 50 cm telescope Akeno.

The observation with a series of 60 sec exposures started at
2022-05-06 13:00:47 UT (6.5 hours after the MAXI/GSC trigger). We
stacked the images with good conditions. Additionally, we performed
the other follow-up observation starting at 2022-05-09 16:12:56 UT. We
did not detect any uncatalogued sources within the XRT error region
(Osborne et al. GCN Circular #32006). We obtained the 5-sigma limits
of the stacked images as follows.

T0+[hour] MID-UT T-EXP[sec] 5-sigma limits
------------------------------------------------------------------------------------------------
8.2 2022-05-06 14:42:28 240 g'>16.9, Rc>17.0, Ic>16.6
34.2 2022-05-07 16:37:41 8580 g'>18.9, Rc>19.5, Ic>18.8
82.9 2022-05-09 17:21:47 6660 g'>19.0, Rc>19.4, Ic>19.0
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time

We used PS1 catalog for flux calibration.
The magnitudes are expressed in the AB system.
The images were processed in real-time through the MITSuME GPU
reduction pipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 1, Pages
4-24; https://github.com/MNiwano/Eclaire).


GRB_name: GRB220507A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32017
SUBJECT: GRB 220507A: AstroSat CZTI detection
DATE:    22/05/11 03:23:31 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

R. Gopalakrishnan (IUCAA), V. Prasad (IUCAA), G. Waratkar (IITB), A. 
Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (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 220507A which was 
also detected by Fermi-GBM (GCN #32009).

The source was clearly detected in the 20-200 keV energy range. The 
light curve peaked at 2022-05-07 10:09:07.35 UT. The measured peak count 
rate associated with the burst is 466 (+188, -32) counts/s above the 
background in the combined data of three quadrants, with a total of 527 
(+145, -147) counts. The local mean background count rate was 366 (+7, 
-10) counts/s. Using cumulative rates, we measure a T90 of 5 (+1, -1) s.

It was also clearly detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range. The light curve peaked at 2022-05-07 
10:09:07.21 UT. The measured peak count rate is 647 (+73, -81) counts/s 
above the background in the combined Veto data of four quadrants, with a 
total of 1796 (+412, -458) counts. The local mean background count rate 
was 1500 (+5, -6) counts/s. We measure a T90 of 6 (+11, -3) 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, ISAC, IUCAA, SAC, 
and PRL. The Indian Space Research Organisation funded, managed, and 
facilitated the project.


GRB_name: GRB220511A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32018
SUBJECT: GRB 220511A: Fermi GBM Final Real-time Localization
DATE:    22/05/11 13:52:24 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 13:41:56 UT on 11 May 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220511A (trigger 673969321.870432 / 220511571).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 285.4, Dec = 17.5 (J2000 degrees, equivalent to J2000 19h 01m, 17d 30'), with a statistical uncertainty of 1.0 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/2022/bn220511571/quicklook/glg_skymap_all_bn220511571.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220511571/quicklook/glg_healpix_all_bn220511571.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220511571/quicklook/glg_lc_medres34_bn220511571.gif


GRB_name: GRB220511A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32019
SUBJECT: GRB 220511A: BALROG localization (Fermi Trigger  673969321/ GRB 220511571)
DATE:    22/05/11 14:03:45 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 673969321
 at 13:41:56 on 11 May 2022 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) = 291.9+/-1.4 deg
Decl.(2000.0) = 19.7+/-1.0 deg
We estimate an additional systematic error of 1 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB220511571/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB220511571/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB220511571/json

                        


GRB_name: GRB220511A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32021
SUBJECT: GRB 220511A: AGILE detection
DATE:    22/05/11 16:54:58 GMT
FROM:    Alessandro Ursi at INAF/IAPS  <alessandro.ursi@gmail.com>

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

The AGILE satellite detected the GRB 220511A at T0 = 2022-05-11 13:41:57
(UTC), reported by Fermi GBM (GCN #32018).

The burst is clearly visible in the AGILE scientific ratemeters of the
SuperAGILE (SA; 20-60 keV), MiniCALorimeter (MCAL; 0.4-100 MeV), and
AntiCoincidence (AC; 50-200 keV) detectors. The event lasted about 3 s and
it released a total number of 410 counts in the SA detector (above a
background rate of 70 Hz), 5150 counts in the MCAL detector (above a
background rate of 1230 Hz), and 15270 counts in the AC detector (above a
background rate of 3500 Hz). The AGILE ratemeter light curves can be found
at http://www.agilescienceapp.it/notices/GRB220511A_AGILE_RM.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: GRB220511A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32022
SUBJECT: Fermi GRB 220511A: Global MASTER-Net observations report 
DATE:    22/05/11 17:15:24 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 220511A ( Fermi GBM team, GCN 32018) errorbox  11983 sec after notice time and 12018 sec after trigger time at 2022-05-11 17:02:15 UT, with upper limit up to  13.3 mag. The observations began at zenith distance = 42 deg. The sun  altitude  is -18.9 deg. 

The galactic latitude b =  5 deg., longitude l = 50 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1969847

We obtain a following upper limits.  

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

   12109 | 2022-05-11 17:02:15 |         MASTER-Amur | (19h 05m 21.07s , +17d 46m 28.2s) |   C |   180 | 12.1 |        
   12455 | 2022-05-11 17:08:01 |         MASTER-Amur | (19h 05m 20.14s , +17d 47m 39.0s) |   C |   180 | 13.3 |        
Filter C is a clear (unfiltred) band. 


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


GRB_name: GRB220511A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32023
SUBJECT: GRB 220511A: Swift/BAT-GUANO arcminute localization
DATE:    22/05/11 22:15:07 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>

James DeLaunay (U Alabama), Aaron Tohuvavohu (U Toronto), Jamie A.
Kennea (PSU), Gayathri Raman (PSU) report:

Swift/BAT did not trigger on GRB 220511A (T0: 2022-05-11T13:47:57
UTC, Fermi/GBM GCN 32018, INTEGRAL/SPI-ACS trig#9912, GECAM trig #
utn220511_134156_GECAMb, AGILE GCN 32021).

The GECAM and INTEGRAL 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 burst is detected in BAT with a duration of ~5 seconds.
The burst occurred during a Swift slew.
The burst location was found in a mosaiced slew image with an SNR of ~10.

The BAT position is
RA, Dec = 287.446, 17.739 deg which is
   RA(J2000)  = 19h 09m 47.04s
   Dec(J2000) =  17d 44â€² 20.4â€³
with an estimated uncertainty of 7 arcmin.

This position is consistent with the Ferm/GBM localization (GCN 32018).

XRT and UVOT follow-up has been requested. Results of follow-up
observations will be reported in future circulars.

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 b
found at: https://www.swift.psu.edu/guano/


GRB_name: GRB220511A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32024
SUBJECT: GRB 220511A: Swift ToO observations
DATE:    22/05/11 23:29:11 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 ToO observation of the Swift/BAT-GUANO GRB 220511A. 
Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021498

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Swift/BAT-GUANO event. 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: GRB220512A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32025
SUBJECT: GRB 220512A: Fermi GBM Final Real-time Localization
DATE:    22/05/12 05:14:12 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 05:03:55 UT on 12 May 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220512A (trigger 674024640.16888 / 220512211).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 128.6, Dec = 84.0 (J2000 degrees, equivalent to J2000 08h 34m, 84d 00'), with a statistical uncertainty of 1.7 degrees.

The angle from the Fermi LAT boresight is 118.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220512211/quicklook/glg_skymap_all_bn220512211.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220512211/quicklook/glg_healpix_all_bn220512211.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220512211/quicklook/glg_lc_medres34_bn220512211.gif


GRB_name: GRB220512A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32026
SUBJECT: Fermi GRB 220512A: Global MASTER-Net observations report 
DATE:    22/05/12 05:30:34 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-OAGH robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) started inspect of the Fermi GRB 220512A ( Fermi GBM team, GCN 32025) errorbox  470 sec after notice time and 509 sec after trigger time at 2022-05-12 05:12:24 UT, with upper limit up to  19.2 mag. The observations began at zenith distance = 55 deg. The sun  altitude  is -32.8 deg. 

The galactic latitude b = 30 deg., longitude l = 129 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1970452

We obtain a following upper limits.  

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

     540 | 2022-05-12 05:12:24 |         MASTER-OAGH | (10h 24m 51.71s , +84d 48m 08.6s) |   C |    60 | 18.2 |        
     540 | 2022-05-12 05:12:24 |         MASTER-OAGH | (10h 19m 25.52s , +85d 11m 06.3s) |   C |    60 | 18.5 |        
     651 | 2022-05-12 05:13:46 |         MASTER-OAGH | (08h 33m 00.84s , +84d 00m 48.6s) |   C |   120 | 19.1 |        
     651 | 2022-05-12 05:13:46 |         MASTER-OAGH | (08h 27m 58.70s , +84d 25m 22.4s) |   C |   120 | 19.0 |        
     803 | 2022-05-12 05:16:07 |         MASTER-OAGH | (08h 28m 04.69s , +84d 25m 48.8s) |   C |   140 | 18.8 |        
     803 | 2022-05-12 05:16:07 |         MASTER-OAGH | (08h 33m 07.25s , +84d 01m 13.8s) |   C |   140 | 18.8 |        
     984 | 2022-05-12 05:18:48 |         MASTER-OAGH | (08h 33m 02.46s , +84d 02m 18.4s) |   C |   180 | 18.9 |        
     984 | 2022-05-12 05:18:48 |         MASTER-OAGH | (08h 27m 58.84s , +84d 26m 56.3s) |   C |   180 | 19.0 |        
    1185 | 2022-05-12 05:22:10 |         MASTER-OAGH | (08h 33m 02.68s , +84d 01m 00.5s) |   C |   180 | 19.2 |        
    1185 | 2022-05-12 05:22:10 |         MASTER-OAGH | (08h 27m 59.98s , +84d 25m 41.9s) |   C |   180 | 19.2 |        
Filter C is a clear (unfiltred) band. 


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


GRB_name: GRB220511A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32027
SUBJECT: GRB 220511A: BOOTES-2/TELMA optical upper limit
DATE:    22/05/12 09:07:40 GMT
FROM:    Youdong HU at IAA-CSIC  <huyoudong072@hotmail.com>

Y.-D. Hu, E. Fernandez-Garcia, T.-R. Sun, A. J. Castro-Tirado, M.D. Caballero-Garcia, R. Sanchez-Ramirez, I. Perez-Garcia (IAA-CSIC), C. Perez del Pulgar, A. Castellon, M. A. Castro Tirado (Univ. de Malaga), R. Fernandez-Munoz (IHSM/UMA-CSIC) and M. Jelinek (ASU-CAS), on behalf of a larger collaboration, report:

Following the detection of GRB 220511A by Fermi (GBM team GCNC 32018), AGILE (Ursi et al. CNCN 32021) and Swift (DeLaunay et al. GCNC 32023), the 0.6m BOOTES-2/TELMA robotic telescope in Algarrobo Costa (Malaga, Spain) pointed to the Swift/BAT-GUANO position on May. 11 at 22:48:06 UT (~9.1 hrs after trigger). No new source is detected in a 11' x 11' FOV within the BAT-GUANO error region in the co-added image (60 x 10 s, clear filter) down to 18.7 mag. This non-detection is consistent with the MASTER results (Lipunov et al. GCNC 32022).

We thank the staff at IHSM/UMA-CSIC La Mayora for its excellent support.


GRB_name: GRB220511A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32028
SUBJECT: GRB 220511A: AstroSat CZTI detection
DATE:    22/05/12 11:33:37 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

R. Gopalakrishnan (IUCAA), V. Prasad (IUCAA), G. Waratkar (IITB), A. 
Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (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 detection of GRB 220511A which was also 
reported by Fermi GBM (GCN #32018), AGILE (Ursi et al., GCN #32021), and 
Swift/BAT-GUANO (DeLaunay et al., GCN #32023).

The source was clearly detected in the 20-200 keV energy range. The 
light curve peaked at 2022-05-11 13:41:57.45 UT. The measured peak count 
rate associated with the burst is  802 (+197, -74) counts/s above the 
background in the combined data of four quadrants, with a total of 1126 
(+156, -184) counts. The local mean background count rate was 525 (+9, 
-9) counts/s. Using cumulative rates, we measure a T90 of 1.8 (+0.8, 
-0.4) 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, ISAC, IUCAA, SAC, 
and PRL. The Indian Space Research Organisation funded, managed, and 
facilitated the project.


GRB_name: GRB220511A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32029
SUBJECT: GRB 220511A: Swift-XRT observations
DATE:    22/05/12 13:22:28 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

V. D'Elia (SSDC & INAF-OAR), A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU),
J. D. Gropp (PSU), J.A. Kennea (PSU), A.P. Beardmore (U. Leicester),
J.P. Osborne (U. Leicester), A. Melandri (INAF-OAB) and P.A. Evans (U.
Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the
Swift/BAT-GUANO-detected burst GRB 220511A (DeLaunay et al. GCN Circ.
32023), collecting 5.0 ks of Photon Counting (PC) mode data between
T0+37.4 ks and T0+49.1 ks. The burst was also detected by Fermi-GBM
(GCN Circ. 32018), AGILE (Ursi et al., GCN 32021) and AstroSat CZTI
(Gopalakrishnan et al., GCN 32028). 

Two uncatalogued X-ray sources have been detected, 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 1:
  RA (J2000):  287.4316  =  19:09:43.59
  Dec (J2000): +17.7297  =  +17:43:46.9
  Error: 5.4 arcsec (radius, 90% conf.)
  Count-rate: (4.7 +/- 1.2)e-3 ct s^-1  
  Distance: 59 arcsec from Swift/BAT-GUANO position.
  Flux: (1.94 +/- 0.51)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 3:
  RA (J2000):  287.5100  =  19:10:2.41
  Dec (J2000): +17.7394  =  +17:44:21.8
  Error: 4.0 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (3.9 [+1.2, -1.0])e-3 ct s^-1   
  Distance: 219 arcsec from Swift/BAT-GUANO position.
  Flux: (7.9 [+2.5, -2.1])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

A catalogued source was also detected.

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/00021498.

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


GRB_name: GRB220511A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32030
SUBJECT: GRB 220511A: Fermi GBM observation
DATE:    22/05/12 16:33:33 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

P. Veres and C. Meegan (both UAH)
report on behalf of the Fermi GBM Team:

"At 13:41:56.87 UT on 11 May 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220511A (trigger 673969321 / 220511571)
which was also detected by Swift/BAT-GUANO (DeLaunay et al., GCN 32023).
The Fermi GBM Final Real-time Localization (GCN 32018) is consistent
with the Swift position.


The angle from the Fermi LAT boresight at the GBM trigger time is 112 degrees.

The GBM light curve consists of a single FRED-like pulse
with a duration (T90) of about 4.2 s (50-300 keV).
The time-averaged spectrum from T0 to T0+5.7 s is best fit by
a power law function with an exponential
high-energy cutoff.  The power law index is -0.85 +/- 0.05 and
the cutoff energy, parameterized as Epeak, is 199 +/- 11 keV.

The event fluence (10-1000 keV) in this time interval is
(7.62 +/- 0.23)E-6 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+0.58 s in the 10-1000 keV band
is 20.3 +/- 0.5 ph/s/cm^2.

A Band function fits the spectrum equally well
with Epeak= 155 +/- 14 keV, alpha = -0.70 +/- 0.08 and beta = 2.18 +/- 0.12.

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: GRB220427A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32032
SUBJECT: GRB 220427A: MeerLICHT afterglow observations
DATE:    22/05/13 08:01:30 GMT
FROM:    Simon de Wet at UCT  <dwtsim002@myuct.ac.za>

S. de Wet (UCT), D.B. Malesani (Radboud), P.M. Vreeswijk (Radboud)
and P.J. Groot (Radboud/UCT/SAAO) report on behalf of the MeerLICHT
consortium:

Following the detection of GRB 220427A by Swift and its X-ray counterpart
(D'Ai et al., GCN 31960), the 0.6m MeerLICHT telescope, located at
Sutherland, South Africa obtained a repeating series of 60 s images in the
q,u,q,g,q,r,q,i,q,z bands. Observations began at 2022-04-27, 23:41:48 UT,
2 hours 41 minutes after the Swift detection, and continued for a further
4.5 hours. The median seeing was 2" under clear skies.

No source is detected at the optical transient position (D'Ai et al., GCN
31960)
in any individual 60 s exposure, hence we co-added all the images in each
filter and performed forced photometry at the transient position. The
afterglow
is detected with a SNR of at least 7 in the g,r,i,z and q bands. We
report the following upper limit and AB magnitudes, at 3 hours 50 minutes
post-trigger:

u > 21.83
g = 21.26 +/- 0.11
q = 21.14 +/- 0.09
r = 20.88 +/- 0.12
i = 20.49 +/- 0.13
z = 19.59 +/- 0.15

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: GRB220511A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32033
SUBJECT: Konus-Wind detection of GRB 220511A
DATE:    22/05/13 13:04:48 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The long GRB 220511A (AGILE detection: Ursi et al., GCN 32021;
AstroSat CZTI detection: Gopalakrishnan  et al., GCN 32028;
Fermi-GBM observation: Veres & Meegan, GCN 32030)
triggered Konus-Wind (KW) at T0=49319.624 s UT (13:41:59.624).

The burst light curve shows a single emission pulse,
which starts at ~T0-1 s and has a total duration of ~6 s.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB220511_T49319/

As observed by Konus-Wind, the burst had
a fluence of (7.8 Â± 1.5)x10^-6 erg/cm^2 and
a 64-ms peak energy flux, measured from T0 + 0.832 s,
of (4.2 Â± 0.7)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 1.5 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -0.75 (-0.19,+0.42),
the high energy photon index beta = -3.1 (-6.9,+0.8),
the peak energy Ep = 159 (-34,+21) keV,
chi2 = 57/59 dof.

All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.


GRB_name: GRB220513A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32034
SUBJECT: GRB 220513A: Fermi GBM Final Real-time Localization
DATE:    22/05/13 20:56:25 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 20:46:08 UT on 13 May 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220513A (trigger 674167573.559368 / 220513865).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 83.9, Dec = -29.2 (J2000 degrees, equivalent to J2000 05h 35m, -29d 11'), with a statistical uncertainty of 12.1 degrees.

The angle from the Fermi LAT boresight is 97.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220513865/quicklook/glg_skymap_all_bn220513865.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220513865/quicklook/glg_healpix_all_bn220513865.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220513865/quicklook/glg_lc_medres34_bn220513865.gif


GRB_name: GRB220513A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32035
SUBJECT: Fermi GRB 220513A: Global MASTER-Net observations report 
DATE:    22/05/13 23:15:19 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-OAFA robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 220513A ( Fermi GBM team, GCN 32034) errorbox  6723 sec after notice time and 6759 sec after trigger time at 2022-05-13 22:38:47 UT, with upper limit up to  17.5 mag. Observations started at twilight.  The observations began at zenith distance = 50 deg. The sun  altitude  is -11.0 deg. 

The galactic latitude b = -28 deg., longitude l = 233 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1972358

We obtain a following upper limits.  

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

    6789 | 2022-05-13 22:38:47 |         MASTER-OAFA | (05h 34m 12.19s , -29d 55m 22.2s) |   C |    60 | 15.6 |        
    7011 | 2022-05-13 22:42:29 |         MASTER-OAFA | (05h 40m 43.43s , -31d 47m 40.1s) |   C |    60 | 16.0 |        
    7236 | 2022-05-13 22:46:14 |         MASTER-OAFA | (05h 45m 21.08s , -28d 00m 23.9s) |   C |    60 | 16.5 |        
    7327 | 2022-05-13 22:47:45 |         MASTER-OAFA | (05h 42m 26.71s , -29d 55m 17.7s) |   C |    60 | 16.4 |        
    7419 | 2022-05-13 22:49:17 |         MASTER-OAFA | (05h 51m 33.06s , -29d 53m 26.4s) |   C |    60 | 16.7 |        
    7510 | 2022-05-13 22:50:48 |         MASTER-OAFA | (05h 19m 13.98s , -28d 00m 30.7s) |   C |    60 | 16.5 |        
    7919 | 2022-05-13 22:57:37 |         MASTER-OAFA | (05h 28m 07.17s , -27d 59m 43.2s) |   C |    60 | 16.9 |        
    8010 | 2022-05-13 22:59:09 |         MASTER-OAFA | (05h 25m 00.33s , -29d 54m 49.0s) |   C |    60 | 17.0 |        
    8102 | 2022-05-13 23:00:40 |         MASTER-OAFA | (05h 34m 04.50s , -29d 55m 35.4s) |   C |    60 | 17.1 |        
    8193 | 2022-05-13 23:02:11 |         MASTER-OAFA | (05h 31m 22.89s , -31d 49m 21.3s) |   C |    60 | 17.1 |        
    8284 | 2022-05-13 23:03:42 |         MASTER-OAFA | (05h 40m 40.43s , -31d 47m 52.9s) |   C |    60 | 16.2 |        
    8376 | 2022-05-13 23:05:14 |         MASTER-OAFA | (05h 36m 16.95s , -28d 01m 11.5s) |   C |    60 | 17.2 |        
    8467 | 2022-05-13 23:06:45 |         MASTER-OAFA | (05h 45m 19.42s , -27d 59m 16.5s) |   C |    60 | 17.5 |        
    8559 | 2022-05-13 23:08:17 |         MASTER-OAFA | (05h 42m 18.77s , -29d 54m 20.1s) |   C |    60 | 17.3 |        
    8650 | 2022-05-13 23:09:48 |         MASTER-OAFA | (05h 51m 28.86s , -29d 53m 05.5s) |   C |    60 | 17.3 |        
Filter C is a clear (unfiltred) band. 


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


GRB_name: GRB220514A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32038
SUBJECT: GRB 220514A: Fermi GBM Final Real-time Localization
DATE:    22/05/14 12:34:56 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 12:24:32 UT on 14 May 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220514A (trigger 674223877.638218 / 220514517).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 145.6, Dec = 13.6 (J2000 degrees, equivalent to J2000 09h 42m, 13d 35'), with a statistical uncertainty of 1.8 degrees.

The angle from the Fermi LAT boresight is 102.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220514517/quicklook/glg_skymap_all_bn220514517.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220514517/quicklook/glg_healpix_all_bn220514517.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220514517/quicklook/glg_lc_medres34_bn220514517.gif


GRB_name: GRB220514A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32039
SUBJECT: GRB 220514A: BALROG localization (Fermi Trigger 674223877 / GRB 220514517)
DATE:    22/05/14 12:48:32 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
674223877 at 12:24:32 on 14 May 2022 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) = 145.7+/-0.8 deg
Decl.(2000.0) = 11.6+/-1.6 deg
We estimate an additional systematic error of 2 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB220514517/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB220514517/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB220514517/json

                        


GRB_name: GRB220514A
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32041
SUBJECT: GRB 220514A: a long GRB detected by INTEGRAL
DATE:    22/05/14 14:11:38 GMT
FROM:    Sandro Mereghetti at IASF-Milano/INAF  <sandro.mereghetti@inaf.it>

S.Mereghetti (INAF, IASF-Milano), D.Gotz (CEA, Saclay), C.Ferrigno,
E.Bozzo, V.Savchenko (ISDC, Versoix), L.Ducci (IAAT, Germany and ISDC,
Versoix) and J.Borkowski (CAMK, Torun) report:

a gamma-ray burst lasting about 70 s has been detected by IBAS in the
IBIS/ISGRI data at 12:24:25  UT of 2022 May 14.

The refined coordinates (J2000) are:
R.A. =   147.6670 deg
DEC. =   +13.1472 deg
with an uncertainty of  1.5   arcmin (90% c.l.).

Due to telemetry saturation, we can estimate only a lower limit of about
4e-6 erg/cm2 on the 20-200 keV fluence.  The burst was detected also by the
Fermi/GBM instrument (GCN Circ. 32038).

A plot of the light curve will  be posted at
http://ibas.iasf-milano.inaf.it/IBAS_Results.html


GRB_name: GRB220514A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32042
SUBJECT: Fermi GRB 220514A: Global MASTER-Net observations report 
DATE:    22/05/14 15:15:15 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 220514A ( Fermi GBM team, GCN 32038) errorbox  7965 sec after notice time and 8004 sec after trigger time at 2022-05-14 14:37:57 UT, with upper limit up to  14.6 mag. The observations began at zenith distance = 68 deg. The sun  altitude  is -20.5 deg. 

The galactic latitude b = 44 deg., longitude l = 221 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1972926

We obtain a following upper limits.  

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

    8035 | 2022-05-14 14:37:57 |         MASTER-Amur | (09h 44m 35.45s , +14d 11m 35.3s) |   C |    60 | 14.6 |        
    8439 | 2022-05-14 14:44:41 |         MASTER-Amur | (09h 55m 27.30s , +12d 17m 17.7s) |   C |    60 | 13.4 |        
Filter C is a clear (unfiltred) band. 


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


GRB_name: GRB220514A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32044
SUBJECT: GRB 220514A: MeerLICHT optical afterglow candidate
DATE:    22/05/14 21:47:44 GMT
FROM:    Simon de Wet at UCT  <dwtsim002@myuct.ac.za>

S. de Wet (UCT), P.M. Vreeswijk (Radboud) and D.B. Malesani (Radboud and
DAWN/NBI) report on behalf of the MeerLICHT consortium:

Following the detection of GRB 220514A by Fermi/GBM (Fermi GBM Team, GCN
32038) and INTEGRAL (Mereghetti et al., GCN 32041), the 0.6m wide-field
MeerLICHT telescope, located at Sutherland, South Africa obtained two 300 s
exposures of a field containing the INTEGRAL position in the q-band
beginning 6.75 hours after the GRB trigger. Based on an existing MeerLICHT
reference image of this field, we detect a new transient candidate within
the INTEGRAL error box with AB magnitude q = 19.89 +\- 0.13 at coordinates:

RA (J2000) = 09:50:39.73 (147.66556d)
Dec (J2000) = 13:09:22.61 (+13.15628d)

calibrated against Gaia DR2. This position is 33" from the centre of the
INTEGRAL error box, and no source is visible at the transient position in
Pan-STARRS images of the field. We suggest this may be the optical
afterglow to GRB 220514A. Further follow-up is encouraged.

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: GRB220514B
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32046
SUBJECT: GRB 220514B: MAXI/GSC detection
DATE:    22/05/15 00:43:04 GMT
FROM:    Yuta Kawakubo at Louisiana State U./CALET  <kawakubo1@lsu.edu>

 Y. Kawakubo (LSU), M. Serino (AGU), 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, S. Sugita, H. Hiramatsu, A. Yoshida (AGU), 
 Y. Tsuboi, W. Iwakiri, J. Kohara (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, M. Tominaga, T. Nagatsuka, T. Kurihara (JAXA), 
 Y. Ueda, S. Ogawa, K. Setoguchi, T. Yoshitake, K. Inaba (Kyoto U.), 
 H. Tsunemi (Osaka U.), 
 M. Yamauchi, Y. Nonaka, T. Sato, R. Hatsuda, R. Fukuoka (Miyazaki U.), 
 K. Yamaoka (Nagoya U.),
 M. Sugizaki (NAOC)
 report on behalf of the MAXI team:
 
The MAXI/GSC nova alert system triggered a bright uncatalogued 
X-ray transient source at 23:24:21 UT on 2022 May 14.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (246.864 deg, 61.440 deg) = (16 27 27, +61 26 23) (J2000) 
with a statistical 90% C.L. elliptical error region 
with long and short radii of 0.26 deg and 0.24 deg, respectively. 
The roll angle of long axis from the north direction is 101.0 deg counterclockwise. 
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
Without assumptions on the source constancy, we obtain a rectangular error
box for the transient source with the following corners:
(246.141, 61.757) deg = (16 24 33, +61 45 25) (J2000) 
(245.940, 61.286) deg = (16 23 45, +61 17 09) (J2000) 
(248.119, 61.055) deg = (16 32 28, +61 03 17) (J2000) 
(248.352, 61.523) deg = (16 33 24, +61 31 22) (J2000) 
The X-ray flux averaged over the scan was 168 +- 26 mCrab
(4.0-10.0keV, 1 sigma error).
There was no significant excess flux in the previous transit at 05/14 21:51 UT 
with an upper limit of 20 mCrab.


GRB_name: GRB220514B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32048
SUBJECT: GRB 220514B: Tiled Swift observations
DATE:    22/05/15 15:30:28 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
MAXI GRB 220514B. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00106

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 MAXI 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: GRB220514A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32051
SUBJECT: GRB 220514A: KAIT Optical Afterglow Confirmation
DATE:    22/05/16 05:57:18 GMT
FROM:    Weikang Zheng at UC Berkeley  <weikang@berkeley.edu>

WeiKang Zheng and Alexei V. Filippenko (UC Berkeley) report on
behalf of the KAIT GRB team:

The 0.76-m Katzman Automatic Imaging Telescope (KAIT), located at
Lick Observatory, responded to GRB 220408A detected by Fermi/GBM
(Fermi GBM Team, GCN 32038) and INTEGRAL (Mereghetti et al., GCN 32041),
starting at 04:21:03 UT, May 15th. Observations were performed
in the clear (roughly R) filter, and the exposure time was 60s per image,
with a total of 64 images were obtained. We marginally detected the
optical afterglow reported by de Wet et al. (GCN 32044) in our coadd image
in clear band, which we measured its brightness of 20.7 +/- 0.3 mag at a
mid time of ~0.69 days after the burst, calibrated to the Pan-STARRS1
catalog.


GRB_name: GRB220511A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32052
SUBJECT: GRB 220511A: Swift-XRT afterglow detection
DATE:    22/05/16 07:47:56 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

V. D'Elia (SSDC & INAF-OAR), A. D'Ai (INAF-IASFPA), D.N. Burrows (PSU),
J. D. Gropp (PSU), J.A. Kennea (PSU), A.P. Beardmore (U. Leicester),
J.P. Osborne (U. Leicester), A. Melandri (INAF-OAB) 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-GUANO-detected burst GRB 220511A (Ursi et al. GCN Circ.
32021). The observations now extend from T0+37.5 ks to T0+285.4 ks. 

Of the sources reported by D'Elia et al. (GCN Circ. 32029), "Source 1"
is fading with 2.4 sigma significance and thus is believed to be the
GRB afterglow. The position of this source is RA, Dec=287.4316,
+17.7297 which is equivalent to:

RA (J2000): 19:09:43.59
Dec(J2000): +17:43:46.9

with an uncertainty of 5.4 arcsec (radius, 90% confidence).  This
position is 59 arcsec from the Swift/BAT-GUANO position. 

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.9 (+0.9, -0.6).

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00021498.
The results of the full analysis of the XRT observations are available
at https://www.swift.ac.uk/ToO_GRBs/00021498.

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


GRB_name: GRB220514B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32053
SUBJECT: GRB 220514B: Swift-XRT observations
DATE:    22/05/16 10:17:35 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. D'Ai (INAF-IASFPA), J. D. Gropp (PSU), J.A. Kennea (PSU), A.
Tohuvavohu (U. Toronto), J.P. Osborne (U. Leicester), K.L. Page (U.
Leicester), A. Melandri (INAF-OAB), T. Sbarrato (INAF-OAB) and P.A.
Evans (U. Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the MAXI-detected
burst GRB 220514B (Y. Kawakubo et al. GCN Circ. 32046) in a series of
observations tiled on the sky. The total exposure time is 1.9 ks,
distributed over 4 tiles; the maximum exposure at a single sky location
was 1.0 ks. The data were collected between T0+57.9 ks and T0+60.1 ks,
and are entirely in Photon Counting (PC) mode. 

No X-ray sources have been detected. The 3-sigma upper limit in the
field (not including the regions where the tiles overlap) ranges from
~0.02 to ~0.04 ct s^-1, corresponding to a 0.3-10 keV observed flux of
6.7e-13 to 1.4e-12 erg cm^-2 s^-1 (assuming a typical GRB spectrum).

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_GRB00106.

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


GRB_name: GRB220514A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32054
SUBJECT: GRB 220514A: Fermi GBM observation
DATE:    22/05/16 15:41:54 GMT
FROM:    Elisabetta Bissaldi at INFN,Bari  <elisabetta.bissaldi@ba.infn.it>

E. Bissaldi (Politecnico and INFN Bari) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:


"At 12:24:32.64 UT on 14 May 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220514A (trigger 674223877 / 220514517),
which was also detected by INTEGRAL (Mereghetti et al. 2022, GCN 32041).

The Fermi GBM Final Real-time Localization has been reported in GCN 32038.

The angle from the Fermi LAT boresight
at the GBM trigger time is 102 degrees.

The GBM light curve shows multiple peaks
with a duration (T90) of about 66 s (50-300 keV).
The time-averaged spectrum from T0-2.8 s to T0+64.8 s is
best fit by a Band function with Epeak = 139 +/- 21 keV,
alpha = -1.25 +/- 0.06, and beta = -1.92 +/- 0.06.

The event fluence (10-1000 keV) in this time interval is
(3.0 +/- 0.1)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+28.9 s in the 10-1000 keV band
is 16.6 +/- 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: GRB220514B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32056
SUBJECT: Konus-Wind detection of GRB 220514B
DATE:    22/05/17 12:09:52 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 GRB 220514B
(MAXI/GSC detection: Kawakubo et al., GCN Circ. 32046)
was detected by Konus-Wind (KW) in the waiting mode.

A Bayesian block analysis of the KW waiting mode data in
the 20-1500 keV band reveals a ~10 sigma count rate increase
over background in the interval from ~T0-26 s to ~T0+74 s,
where T0 = T0(MAXI) = 84261 s UT (23:24:21).

The K-W light curve of this burst is available at
http://www.ioffe.ru/LEA/GRBs/GRB220514B/

As observed by Konus-Wind, the burst had a fluence of
6.59(-1.19,+1.61)x10^-6 erg/cm2 and a 2.944-s peak flux,
measured from ~T0-14.4 s, of 1.54(-0.43,+0.50)x10^-7 erg/cm2/s
(both in the 20 - 1500 keV energy range).

Modeling the K-W 3-channel time-integrated spectrum
(from ~T0-26.2 s to ~T0+73.9 s)
by a power law with exponential cutoff (CPL) model
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -0.82(-0.21,+0.33) and Ep = 263(-65,+112) keV.

All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.


GRB_name: GRB220506A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32057
SUBJECT: Konus-Wind detection of GRB 220506A
DATE:    22/05/17 14:27:08 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

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

The long-duration GRB 220506A
(MAXI/GSC detection: Urabe et al., GCN Circ. 32001)
was detected by Konus-Wind (KW) in the waiting mode.

A Bayesian block analysis of the KW waiting mode data in
the 20-1500 keV band reveals a ~6 sigma count rate increase
over background in the interval from ~T0-115 s to ~T0-89 s,
where T0 = T0(MAXI) = 23295 s UT (06:28:15).

The K-W light curve of this burst is available at
http://www.ioffe.ru/LEA/GRBs/GRB220506A/

As observed by Konus-Wind, the burst had a fluence of
1.46(-0.10,+1.13)x10^-6 erg/cm2 and a 2.944-s peak flux,
measured from ~T0-112 s, of 1.14(-0.28,+0.92)x10^-7 erg/cm2/s
(both in the 20 - 1500 keV energy range).

Modeling the K-W 3-channel time-integrated spectrum
(from ~T0-115 s to ~T0-89 s)
by a power law with exponential cutoff (CPL) model
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha > -1.0 and Ep = 110(-16,+70) keV.

All the quoted errors are estimated at the 1 sigma confidence level.
All the presented results are preliminary.


GRB_name: GRB220514A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32058
SUBJECT: GRB 220514A: GRANDMA Optical Afterglow Observations
DATE:    22/05/17 21:18:06 GMT
FROM:    Cristina Andrade at UMN  <andra104@umn.edu>

S. Yan (THU), C. Andrade (UMN), S. Beradze (AbAO), P.A. Duverne (IJCLAB),
K. Kruiswijk (UCLouvain), G. Raaijmakers (GRAPPA), M. Vardosanidze (AbAO),
D. Turpin (CEA/Irfu, Saclay), M. Pilloix, S. Antier,
A. de Ugarte Postigo (CNRS-OCA-ARTEMIS), D. A. Kann (IAA-CSIC), A. Simon,
A. Baransky (Kyiv Univ), V. Godunova (IC ICAMER), R. Inasaridze,
R. Natsvlishvili, N. Kochiashvili, V. Aivazyan, G. Kapanadze,
D. Datashvili (AbAO),  C. Rinner, Z. Benkhaldoun (OUCA), M. Freeberg (KNC),
A. Kaouech (OUCA/KNC), F. Guo,  X. Wang,  S. X. Wang (THU), Y. Wang (NAOC),
S. Karpov, M. Masek, M. Prouza (FZU)
report on behalf of the GRANDMA collaboration:

The GRANDMA telescope network responded to the alert of GRB 220514A
(Fermi GBM team GCN 32038, Biltzinger et al. GCN 32039, S.
Mereghetti et al. GCN 32041).

The first observations were obtained with TNT, starting
1.57 h after the Fermi/GBM and INTEGRAL/IBAS trigger time, in which we
detect the afterglow.

We furthermore detect the optical afterglow with MOSS 7.95h after trigger
at a magnitude of 20.18 +/- 0.15 mag in a Clear image. The afterglow is
also detected in a stack by the 2.2m CAHA equipped with the CAFOS
instrument 9.58h after trigger in the i' band at 19.86 +/- 0.16 mag.
Upper limits are given at 3 sigma.

The following table displays part of our photometry with magnitudes
given in the AB system and calibrated with respect to field stars from
the Pan-STARRS and APASS catalogs, using the MUPHOTEN pipeline (Duverne et
al. 2021). The FRAM image has been calibrated versus GAIA DR2 G magnitudes.


T-T0 (hr)| MJD      | Observatory| Exposure  | Filter | Mag +/- err (AB)
________________________________________________________________
1.57    |59713.58235| TNT        | 3 x 300 s | r'     | 18.84 +/- 0.07
7.66    |59713.83624| AbAO-T70   | 9 x  60 s | R      | > 16.9
7.95    |59713.84841| MOSS       |45 x  60 s | Clear  | 20.18 +/- 0.15
8.23    |59713.86003| KNC-HAO    |15 x 120 s | R      | > 19.4
8.50    |59713.86140| FRAM       |15 x 120 s | Clear  | > 18.5
9.58    |59713.91610| CAHA/CAFOS |10 x 150 s | i'     | 19.86 +/- 0.16
15.06   |59714.14438| KNC-T21    |17 x 180 s | Rc     | > 19.3

T-T0 is the delay between the start of the observation and the IBAS
trigger time.

The detections and upper limits are consistent with previous reports of
detections by MeerLICHT (de Wet et al. GCN 32044) and KAIT (Zheng et al.
GCN 32051) and upper limits by MASTER (Lipunov et al. GCN 32042 & GCN
32043).

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: GRB220514A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32059
SUBJECT: GRB 220514A: MITSuME Akeno optical observation
DATE:    22/05/18 03:30:34 GMT
FROM:    Katsuhiro L. Murata at Nagoya U  <murata@u.phys.nagoya-u.ac.jp>

K. L. Murata, R. Hosokawa, Y. Imai,  N. Ito,  M. Sasada, M. Niwano, Y.
Takamatsu, S. Sato, M. Tateda, T. Hattori, Y. Yatsu, and N. Kawai (Tokyo
Tech) report on behalf of the MITSuME collaboration:

We observed the field of GRB 220514A (Fermi GBM team et al. GCN Circular
#32038, Biltzinger et al. GCN Circular #32039, Mereghetti et al. GCN
Circular #32041, Lipunov et al. GCN Circular #32042, de Wet et al. GCN
Circular #32044, Zheng et al. GCN Circular #32051, Bissaldi et al. GCN
Circular #32054, Yan et al. GCN Circular #32058) with the optical three
color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope
Akeno.

The observation with a series of 60 sec exposures started at 2022-05-14
12:25:15 UT(47 seconds after the Fermi/GBM trigger). We stacked the images
with good conditions. Here we report magnitudes by the forced-photometry at
the position of the optical afterglow (GCN Circulars # 32044, #32051,
#32058) and 5-sigma limits.

T0+[hour] |MID-UT | T-EXP[sec] | magnitudes of forced-photometry | 5-sigma
limits
------------------------------------------------------------------------------------------------
0.77 | 2022-05-14 13:10:41 | 660 | g' = 19.6 +/- 0.9, Rc = 19.3 +/- 0.7, Ic
= 18.3 +/- 0.5 | g' > 17.7, Rc > 18.0, Ic > 17.5
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used the PS1 catalog for flux calibration. The magnitudes are expressed
in the AB system. The images were processed in real-time through the
MITSuME GPU reduction pipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 1,
Pages 4-24; https://github.com/MNiwano/Eclaire).


GRB_name: GRB220518A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32060
SUBJECT: GRB 220518A: Swift detection of a burst
DATE:    22/05/18 06:47:24 GMT
FROM:    Kim Page at U.of Leicester  <kimlpage1978@gmail.com>

J.D. Gropp (PSU), K. L. Page (U Leicester),
T. M. Parsotan (GSFC/UMBC/CRESSTII), B. Sbarufatti (PSU) and
M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 06:19:20 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 220518A (trigger= 1107050).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 55.369, -47.571 which is 
   RA(J2000) = +03h 41m 29s
   Dec(J2000) = -47d 34' 15"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  There are currently no BAT light curve data available
at this time. 

The XRT began observing the field at 06:21:27.1 UT, 126.4 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 55.34297, -47.58392
which is equivalent to:
   RA(J2000)  = 03h 41m 22.31s
   Dec(J2000) = -47d 35' 02.1"
with an uncertainty of 1.9 arcseconds (radius, 90% containment). This
location is 78 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 (9.33 x
10^19 cm^-2, Willingale et al. 2013), with an excess column of 5
(+3.25/-2.72) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 129 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. 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 0.008. 

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: GRB220518A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32061
SUBJECT: Swift GRB 220518A: Global MASTER-Net observations report 
DATE:    22/05/18 08:36:38 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-OAFA robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Argentina (OAFA observatory of San Juan National University) was pointed to the Swift GRB 220518A ( J.D. Gropp et al., GCN 32060) errorbox  6501 sec after notice time and 6534 sec after trigger time at 2022-05-18 08:08:15 UT, with upper limit up to  15.6 mag. The observations began at zenith distance = 87 deg. The sun  altitude  is -40.1 deg. 

The galactic latitude b = -51 deg., longitude l = 256 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1977169

We obtain a following upper limits.  

Tmid-T0  |          Site       |Filt.| Expt. | Limit| Comment
_________|_____________________|_____|_______|______|________

    6565 |         MASTER-OAFA |   C |    60 | 14.3 |        
    7687 |         MASTER-OAFA |   C |   180 | 15.3 |        
    7947 |         MASTER-OAFA |   C |    60 | 15.6 |        
Filter C is a clear (unfiltred) band. 


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


GRB_name: GRB220518A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32062
SUBJECT: GRB 220518A: Enhanced Swift-XRT position
DATE:    22/05/18 10:12:12 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 1717 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 220518A, 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 = 55.34331, -47.58376 which is equivalent
to:

RA (J2000): 03h 41m 22.39s
Dec (J2000): -47d 35' 01.5"

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: GRB220518A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32063
SUBJECT: GRB 220518A: Swift/UVOT Detection
DATE:    22/05/18 15:09:29 GMT
FROM:    Samantha Oates at MSSL  <samantha.oates@alumni.ucl.ac.uk>

S. R. Oates (U.Birmingham) and J. D. Gropp (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 220518A
129 s after the BAT trigger (Gropp et al., GCN Circ. 32060).
A source consistent with the enhanced XRT position
(Beardmore et al. GCN Circ. 32062)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
   RA  (J2000) =  03:41:22.29 =  55.34289 (deg.)
   Dec (J2000) = -47:35:00.3  = -47.58342 (deg.)
with an estimated uncertainty of 0.55 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)        129          279         147         20.00 +/- 0.25
white             621         1717         334         20.49 +/- 0.23
v                 671         1767         136         >19.0
b                 597         1861         131         >20.1
u (FC)            341          591         246         >19.7
u                 341         1841         324         >19.9
w1               1103         1296          39         >18.4


The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.008 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB220518B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32064
SUBJECT: GRB 220518B: Fermi GBM Final Real-time Localization
DATE:    22/05/18 17:22:18 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 17:11:52 UT on 18 May 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220518B (trigger 674586717.27941 / 220518717).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 293.3, Dec = -66.2 (J2000 degrees, equivalent to J2000 19h 33m, -66d 12'), with a statistical uncertainty of 8.4 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/2022/bn220518717/quicklook/glg_skymap_all_bn220518717.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220518717/quicklook/glg_healpix_all_bn220518717.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220518717/quicklook/glg_lc_medres34_bn220518717.gif


GRB_name: GRB220518B
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32066
SUBJECT: Fermi GRB 220518B: Global MASTER-Net observations report 
DATE:    22/05/18 23:15:24 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-OAFA robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 220518B ( Fermi GBM team, GCN 32064) errorbox  20073 sec after notice time and 20113 sec after trigger time at 2022-05-18 22:47:05 UT, with upper limit up to  15.9 mag. Observations started at twilight.  The observations began at zenith distance = 78 deg. The sun  altitude  is -13.2 deg. 

The galactic latitude b = -29 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=1977596

We obtain a following upper limits.  

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

   20143 | 2022-05-18 22:47:05 |         MASTER-OAFA | (19h 11m 47.26s , -66d 01m 28.7s) |   C |    60 | 12.0 |        
   20332 | 2022-05-18 22:50:13 |         MASTER-OAFA | (19h 38m 53.32s , -69d 51m 52.3s) |   C |    60 | 15.9 |        
   20610 | 2022-05-18 22:54:51 |         MASTER-OAFA | (18h 56m 16.81s , -69d 50m 05.5s) |   C |    60 | 13.9 |        
   20703 | 2022-05-18 22:56:25 |         MASTER-OAFA | (19h 18m 55.06s , -68d 27m 46.9s) |   C |    60 | 15.6 |        
   20800 | 2022-05-18 22:58:02 |         MASTER-OAFA | (19h 48m 13.61s , -66d 01m 47.3s) |   C |    60 | 15.1 |        
Filter C is a clear (unfiltred) band. 


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


GRB_name: GRB220518A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32067
SUBJECT: GRB 220518A: Swift-XRT refined Analysis
DATE:    22/05/19 00:06:54 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

J.A. Kennea (PSU), A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU),
J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore
(U. Leicester), A. Melandri (INAF-OAB), T. Sbarrato (INAF-OAB), P.
D'Avanzo (INAF-OAB) and J.D. Gropp report on behalf of the Swift-XRT
team:

We have analysed 6.5 ks of XRT data for GRB 220518A (Gropp et al. GCN
Circ. 32060), from 133 s to 53.3 ks after the  BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position
for this burst was given by Beardmore et al. (GCN Circ. 32062).

The late-time light curve (from T0+7.3 ks) can be modelled with a
power-law decay with a decay index of alpha=1.3 (+/-0.4).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.85 (+0.15, -0.14). The
best-fitting absorption column is  2.7 (+3.1, -1.8) x 10^20 cm^-2,
consistent with the Galactic value of 9.3 x 10^19 cm^-2 (Willingale et
al. 2013). The counts to observed (unabsorbed) 0.3-10 keV flux
conversion factor deduced from this spectrum  is 3.5 x 10^-11 (3.7 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.7 (+3.1, -1.8) x 10^20 cm^-2
Galactic foreground: 9.3 x 10^19 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.85 (+0.15, -0.14)

If the light curve continues to decay with a power-law decay index of
1.3, the count rate at T+24 hours will be 3.5 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x
10^-13 (1.3 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/01107050.

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


GRB_name: GRB220518A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32069
SUBJECT: GRB 220518A: Swift-BAT refined analysis
DATE:    22/05/19 22:19:52 GMT
FROM:    Tyler Parsotan at UMBC/GSFC/CRESST II  <parsotat@umbc.edu>

S. Laha (GSFC/UMBC), S. D. Barthelmy (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-239 to T+963 sec from the recent telemetry downlink,

we report further analysis of BAT GRB 220518A (trigger #1107050)

(Gropp et al., GCN 32060).  The BAT ground-calculated position is

RA, Dec = 55.340, -47.593 deg which is 

   RA(J2000)  =  03h 41m 21.6s 

   Dec(J2000) = -47d 35' 36.3" 

with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).

The partial coding was 51%.

 

The light curve has a peak at the trigger time and potential precursor 

emission occuring slightly before the BAT trigger time. 

T90 (15-350 keV) is 12.29 +- 3.07 sec (estimated error including systematics).

The time-averaged spectrum from T-8.36 to T+7.58 sec is best fit by a simple

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

1.71 +- 0.21.  The fluence in the 15-150 keV band is 5.7 +- 0.8 x 10^-07 erg/cm2.

The 1-sec peak photon flux measured from T+0.07 sec in the 15-150 keV band

is 1.8 +- 0.3 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/1107050/BA/

 

 


GRB_name: GRB220514A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32070
SUBJECT: GRB 220514A: AstroSat CZTI detection
DATE:    22/05/20 05:16:27 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

R. Gopalakrishnan (IUCAA), V. Prasad (IUCAA), G. Waratkar (IITB), A. 
Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (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 detection of a long GRB 220514A, which was 
also reported by Fermi GBM ( GCN 32028), INTEGRAL (Mereghetti et al., 
GCN 32041) and BALROG ( Biltzinger et al. GCN 32029).

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 
2022-05-14 at 12:24:58.50 UT. The measured peak count rate associated 
with the burst is 346 (+51, -30) counts/s above the background in the 
combined data of four quadrants, with a total of 4001 (+588, -793) 
counts. The local mean background count rate was 561 (+2, -3) counts/s. 
Using cumulative rates, we measure a T90 of 54 (+9, -5) s.

It was also clearly detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range. The light curve peaks at 2022-05-14 at 
12:24:57.99 UT. The measured peak count rate is 401 (+75, -80) counts/s 
above the background in the combined Veto data of four quadrants, with a 
total of 2095 (+596, -592) counts. The local mean background count rate 
was 1935 (+3, -4) counts/s. We measure a T90 of 29 (+4, -8) s from the 
cumulative Veto light curve.

This is the 500th GRB detected by AstroSat CZTI since its launch in 
September 2015, with an average rate of 75 GRBs/year.

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, ISAC, IUCAA, SAC, 
and PRL. The Indian Space Research Organisation funded, managed, and 
facilitated the project.


GRB_name: GRB220519A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32072
SUBJECT: IPN triangulation of GRB 220519A
DATE:    22/05/20 20:05:08 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 HEND/Mars-Odyssey team,

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

A short-duration GRB 220519A
has been detected by Konus-Wind, INTEGRAL (SPI-ACS),
and Mars-Odyssey (HEND), so far, at about 42339 s UT (11:45:39).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
 ---------------------------------------------
  RA(2000), deg                 Dec(2000), deg
 ---------------------------------------------
 Center:
  357.784 (23h 51m 08s)  -9.720 ( -9d 43' 11")
 Corners:
  357.477 (23h 49m 54s)  -9.525 ( -9d 31' 30")
  357.634 (23h 50m 32s) -10.012 (-10d 00' 45")
  358.089 (23h 52m 21s)  -9.905 ( -9d 54' 18")
  357.931 (23h 51m 43s)  -9.420 ( -9d 25' 14")
 ---------------------------------------------
The error box area is 843 sq. arcmin, and its maximum
dimension is 43 arcmin (the minimum one is 28 arcmin).
The Sun distance was 65 deg.

This box may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220519_T42339/IPN/

The time history and spectrum will be given in forthcoming GCN Circulars.


GRB_name: GRB220519A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32073
SUBJECT: Konus-Wind detection of GRB 220519A
DATE:    22/05/20 20:10:25 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 short-duration GRB 220519A
(IPN triangulation: Kozyrev at al., GCN Circ. 32072)
triggered Konus-Wind at T0=42339.403 s UT (11:45:39.403).

The burst light curve shows a single emission pulse,
which starts at T0-0.1 s and has a total duration of ~0.7 s.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB220519_T42339/

As observed by Konus-Wind, the burst
had a fluence of 1.66(-0.02,+0.48)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0-0.048 s,
of 6.05(-3.24,+3.66)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

Since the main fraction of the burst emission was detected
before the trigger, the spectral analysis was performed using
the KW 3-channel light curve data.

Modelling the KW 3-channel time-integrated spectrum
(measured from T0-0.096 s to T0+0.640 s)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep),
yields alpha = -0.13(-0.35,+0.44) and Ep = 507(-77,+117) keV.

All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.


GRB_name: GRB220521A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32075
SUBJECT: GRB 220521A: Fermi GBM Final Real-time Localization
DATE:    22/05/21 23:30:48 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 SHORT GRB

At 23:20:21 UT on 21 May 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220521A (trigger 674868026.727134 / 220521972).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 292.6, Dec = 3.9 (J2000 degrees, equivalent to J2000 19h 30m, 3d 53'), with a statistical uncertainty of 13.6 degrees.

The angle from the Fermi LAT boresight is 88.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220521972/quicklook/glg_skymap_all_bn220521972.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220521972/quicklook/glg_healpix_all_bn220521972.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220521972/quicklook/glg_lc_medres34_bn220521972.gif


GRB_name: GRB220521A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32076
SUBJECT: GRB 220521A: Swift detection of a burst
DATE:    22/05/21 23:31:51 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

S. Dichiara (PSU), J.D. Gropp (PSU), D. M. Palmer (LANL) and
B. Sbarufatti (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 23:20:21 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 220521A (trigger=1107466).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 275.197, +10.384 which is 
   RA(J2000) = 18h 20m 47s
   Dec(J2000) = +10d 23' 03"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a double-peaked
structure with a duration of about 15 sec.  The peak count rate
was ~4000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 23:21:57.7 UT, 96.3 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 275.22891, 10.37262 which is equivalent
to:
   RA(J2000)  = 18h 20m 54.94s
   Dec(J2000) = +10d 22' 21.4"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 120 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 1.87
x 10^21 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 99 seconds after the BAT trigger. No credible afterglow candidate has
been found in the initial data products. Results from the 2.7'x2.7' sub-image
are not available at this time. 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 0.185. 

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: GRB220521A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32077
SUBJECT: GRB 220521A: Prompt enhanced Swift-XRT position
DATE:    22/05/21 23:44:42 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 220521A, we find an
enhanced XRT position of the afterglow: RA, Dec: 275.22978, 10.37221
which is equivalent to:
   RA (J2000)  = 18 20 55.15
   Dec (J2000) = +10 22 19.9
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/1107466.

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: GRB220521A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32078
SUBJECT: GRB 220521A: NOT optical afterglow detection
DATE:    22/05/22 00:09:27 GMT
FROM:    Daniele B Malesani at Radboud U  <d.malesani@astro.ru.nl>

D. B. Malesani (Radboud Univ. and DAWN/NBI) and T. Pursimo (NOT) report 
on behalf of more people:

We observed the field of GRB 220521A (Dichiara et al., GCN 32076) with 
the Nordic Optical Telescope (NOT) equipped with the ALFOSC imager. In a 
300-s exposure beginning on 2022 May 21.983 UT (0.248 hr after the GRB), 
we detect a new object consistent with the UVOT-enhanced X-ray position 
(Evans, GCN 32077), at J2000 coordinates:

RA = 18:20:55.13
Dec = +10:22:20.5

Calibration is against the Gaia catalog, with an expected uncertainty < 
0.3".

Photometry against nearby Pan-STARRS calibrators yields r = 21.06 +- 
0.03 AB. Given the consistency with the X-ray position and the lack of 
detection in the Pan-STARRS archival images, we conclude that this 
source is the optical afterglow of GRB 220521A.


GRB_name: GRB220521A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32079
SUBJECT: GRB 220521A: NOT spectroscopic redshift
DATE:    22/05/22 02:04:13 GMT
FROM:    Daniele B Malesani at Radboud U  <d.malesani@astro.ru.nl>

J. P. U. Fynbo (DAWN/NBI), Z. Zhu (NAO/CAS, HUST), D. Xu (NAOC/CAS), D. 
B. Malesani (Radboud Univ. and DAWN/NBI), T. Pursimo (NOT), K. 
Matilainen (NOT), report on behalf of a larger collaboration:

Spectroscopy of the optical counterpart of GRB 220521A (Dichiara et al., 
GCN 32076; Malesani & Pursimo, GCN 32078) was secured using the Nordic 
Optical Telescope (NOT) equipped with the ALFOSC spectrograph. Grism #4 
was used, covering the wavelength range 3650-9500 AA. Our first spectrum 
(1200 s exposure time) started on May 22.004 UT (0.76 hr after the GRB).

Preliminary analysis of the data, using archival calibration files, 
reveals a bright continuum in the red part, with a clear break around 
8150 AA, which we interpret as due to Lyman alpha. We also identify the 
Lyman limit, the Lyman forest, and several metal absorption features 
(among which Si II 1260, O I 1302, Si II 1304, C II 1334, Si IV 
1393,1402), which allow to determine z = 5.6.

The precision of the redshift can be improved after utilizing updated 
calibration files.


GRB_name: GRB220522A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32080
SUBJECT: GRB 220522A: Fermi GBM Final Real-time Localization
DATE:    22/05/22 02:49:28 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 02:39:00 UT on 22 May 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220522A (trigger 674879945.37741 / 220522110).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 32.6, Dec = 4.0 (J2000 degrees, equivalent to J2000 02h 10m, 4d 00'), with a statistical uncertainty of 10.7 degrees.

The angle from the Fermi LAT boresight is 37.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220522110/quicklook/glg_skymap_all_bn220522110.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220522110/quicklook/glg_healpix_all_bn220522110.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220522110/quicklook/glg_lc_medres34_bn220522110.gif


GRB_name: GRB220521A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32081
SUBJECT: GRB 220521A: Enhanced Swift-XRT position
DATE:    22/05/22 07:37:30 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 441 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 220521A, 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 = 275.22990, +10.37175 which is equivalent
to:

RA (J2000): 18h 20m 55.18s
Dec (J2000): +10d 22' 18.3"

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: GRB220521A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32082
SUBJECT: GRB 220521A: SAO RAS optical observations
DATE:    22/05/22 09:06:22 GMT
FROM:    Moskvitin Alexander at SAO RAS  <mosk@sao.ru>

Goranskij V. P. (SAI, Moscow University) and Moskvitin A. S. (Special
Astrophysical Observatory of RAS) report on behalf of a larger
collaboration:

We observed the field of the GRB 220521A (Dichiara et al., GCN 32076;
Evans, GCN 32077) with the SAO RAS 1-m telescope Zeiss-1000
+ CCD-photometer. The observations started 16.6 minutes
after the trigger. We obtained 200 sec. exposures in V, Rc, Ic filters.

The OT (Malesani & Pursimo, GCN 32078; Fynbo et al., GCN 32079)
is clearly detected in Ic and Rc bands (with the brightness of
I = 17.82 +/- 0.04; R = 20.3 +/- 0.2) and not detected in V band
down to the limiting magnitude of V_lim ~ 21.4 (T_mid-T0 = 22.8 min).
Preliminary photometry is based on nearby stars of PS1 catalogue,
gri --> V, R, I by Lupton 2005 transformations.


GRB_name: GRB220522A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32084
SUBJECT: Fermi GRB 220522A: Global MASTER-Net observations report 
DATE:    22/05/22 10:15:26 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-OAFA robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 220522A ( Fermi GBM team, GCN 32080) errorbox  25131 sec after notice time and 25168 sec after trigger time at 2022-05-22 09:38:29 UT, with upper limit up to  17.8 mag. The observations began at zenith distance = 69 deg. The sun  altitude  is -21.3 deg. 

The galactic latitude b = -53 deg., longitude l = 158 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1980647

We obtain a following upper limits.  

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

   25199 | 2022-05-22 09:38:29 |         MASTER-OAFA | (01h 25m 33.24s , -01d 29m 05.9s) |   C |    60 | 12.1 |        
   25290 | 2022-05-22 09:40:00 |         MASTER-OAFA | (01h 33m 33.22s , -01d 30m 35.2s) |   C |    60 | 11.9 |        
   25553 | 2022-05-22 09:44:23 |         MASTER-OAFA | (01h 48m 48.07s , -03d 23m 42.2s) |   C |    60 | 12.8 |        
   25828 | 2022-05-22 09:48:58 |         MASTER-OAFA | (01h 40m 43.30s , +00d 23m 11.7s) |   C |    60 | 13.9 |        
   25919 | 2022-05-22 09:50:29 |         MASTER-OAFA | (01h 48m 48.37s , +00d 23m 47.7s) |   C |    60 | 13.9 |        
   26010 | 2022-05-22 09:52:00 |         MASTER-OAFA | (01h 56m 05.57s , +02d 17m 47.7s) |   C |    60 | 12.3 |        
   26192 | 2022-05-22 09:55:02 |         MASTER-OAFA | (01h 56m 19.31s , +04d 13m 20.4s) |   C |    60 | 13.6 |        
   26375 | 2022-05-22 09:58:04 |         MASTER-OAFA | (01h 56m 00.09s , +00d 23m 31.4s) |   C |    60 | 17.8 |        
   26466 | 2022-05-22 09:59:36 |         MASTER-OAFA | (02h 03m 57.63s , +00d 25m 11.8s) |   C |    60 | 16.4 |        
   26557 | 2022-05-22 10:01:07 |         MASTER-OAFA | (01h 55m 57.43s , -01d 30m 15.9s) |   C |    60 | 15.9 |        
   26648 | 2022-05-22 10:02:38 |         MASTER-OAFA | (02h 03m 59.46s , -01d 28m 57.7s) |   C |    60 | 15.2 |        
   26739 | 2022-05-22 10:04:09 |         MASTER-OAFA | (02h 11m 05.89s , +00d 25m 34.9s) |   C |    60 | 14.6 |        
   26831 | 2022-05-22 10:05:41 |         MASTER-OAFA | (02h 19m 12.75s , +00d 24m 43.5s) |   C |    60 | 14.5 |        
   26922 | 2022-05-22 10:07:12 |         MASTER-OAFA | (01h 56m 03.70s , +02d 17m 21.1s) |   C |    60 | 14.7 |        
   27013 | 2022-05-22 10:08:43 |         MASTER-OAFA | (02h 04m 10.53s , +02d 17m 59.5s) |   C |    60 | 15.2 |        
Filter C is a clear (unfiltred) band. 


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


GRB_name: GRB220521A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32085
SUBJECT: GRB 220521A: Swift/UVOT Upper Limits
DATE:    22/05/22 13:57:22 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

N. P. M. Kuin (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 220521A
100 s after the BAT trigger (Dichiara et al., GCN Circ. 32076).No optical
afterglow consistent with the XRT position (Evans et al. GCN Circ. 32081)
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           100          250          147         >20.8
u_FC               312          548          232         >19.2
white              100         4178          344         >21.5
v                 4389         4589          197         >19.5
b                 3773         3973          197         >20.4
u                  312         5050          278         >19.4
w1                4798         4998          197         >20.2
m2                4593         4793          197         >19.7
w2                4184         4383          197         >19.7

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.185 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB220521A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32086
SUBJECT: GRB 220521A: Swift-XRT refined Analysis
DATE:    22/05/22 14:22:11 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. Tohuvavohu (U. Toronto), B. Sbarufatti (PSU), K.L. Page (U.
Leicester), A.P. Beardmore (U. Leicester), P.A. Evans (U. Leicester),
T. Sbarrato (INAF-OAB), P. D'Avanzo (INAF-OAB), M.G. Bernardini
(INAF-OAB), D.N. Burrows (PSU) and S. Dichiara report on behalf of the
Swift-XRT team:

We have analysed 8.4 ks of XRT data for GRB 220521A (Dichiara et al.
GCN Circ. 32076), from 104 s to 45.1 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. 32077).

The late-time light curve (from T0+3.8 ks) can be modelled with a
power-law decay with a decay index of alpha=1.53 (+0.27, -0.23).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.90 (+0.26, -0.16). The
best-fitting absorption column is  1.94 (+0.96, -0.07) x 10^21 cm^-2,
consistent with the Galactic value of 1.9 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 3.7 x 10^-11 (4.8 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.94 (+0.96, -0.07) x 10^21 cm^-2
Galactic foreground: 1.9 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.90 (+0.26, -0.16)

If the light curve continues to decay with a power-law decay index of
1.53, the count rate at T+24 hours will be 1.0 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.7 x
10^-14 (4.9 x 10^-14) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/01107466.

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


GRB_name: GRB220521A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32087
SUBJECT: GRB 220521A: RATIR Optical and NIR Observations 
DATE:    22/05/22 15:02:40 GMT
FROM:    Alan M Watson at UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), William H. Lee (UNAM), Alexander
Kutyrev (GSFC), Eleonora Troja (UTV), Michael G. Richer (UNAM), Ori Fox (STScI),
J. Xavier Prochaska (UCSC), Josh Bloom (UCB), Enrico Ramirez-Ruiz (UCSC), JesÃºs
GonzÃ¡lez (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Harvey Moseley (GSFC), Rosa L.
Becerra (UNAM), Simone Dichiara (PSU), and OcÃ©lotl LÃ³pez (UNAM) report:

We observed the field of GRB 220521A (Dichiara et al., GCN Circ. 32076) with the
Reionization and Transients Infrared Camera (RATIR) on the 1.5m Harold Johnson
Telescope at the Observatorio AstronÃ³mico Nacional on Sierra San Pedro MÃ¡rtir
from 2022/05 22.22 to 2022/05 22.47 UTC (6.04 to 12.03 hours after the BAT
trigger), obtaining a total of 2.98 hours exposure in the r and i bands and 1.23
hours exposure in the Z, Y, J, and H bands.

For a source within the enhanced (Evans et al., GCN Circ. 32081) Swift-XRT error
circle, in comparison with the USNO-B1 and 2MASS catalogs, we obtain the
following 3-sigma upper limits:

  r > 23.07
  i > 22.77
  Z > 21.13
  Y > 21.87
  J > 21.75
  H > 21.30

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB.

Our non-detection of the NOT afterglow (Malesani & Pursimo, GCN Circ. 32078) is
consistent with a temporal power-law index steeper than about -0.5.

We thank the staff of the Observatorio AstronÃ³mico Nacional in San Pedro 
MÃ¡rtir.


GRB_name: GRB220521A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32088
SUBJECT: GRB 220521A: Sintesz-Newton/CrAO optical upper limit
DATE:    22/05/22 15:17:22 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Nazarov (CrAO), A. Pozanenko (IKI), S. Belkin (IKI, HSE), N. Pankov 
(HSE)  report on behalf of IKI GRB FuN:

We observed  the GRB 220521A (Dichiara et al., GCN 32076; Fermi GBM 
Team, GCN 32075) with Sintesz-Newton 350mm f/5 telescope of CrAO 
observatory. Observation started on 2022-05-22 (UT) 01:05:40. The series 
consists of images with an exposure of 60 s in a Clear filter.

The optical afterglow  (Malesani et al., GCN 32078; Fynbo et al., GCN 
32079; Goranskij et al., GCN 32082) is not detected in the stacked image.

Preliminary photometry of the stacked images is following

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

2022-05-22 01:05:40   0.07626  Clear 9*60    n/d  n/d   18.2


The photometry is based on nearby USNO-B1.0 (R2) stars
RA DEC R2
18:21:04.76880 +10:21:04.7232 16.26
18:21:07.39800 +10:20:37.5000 16.73


GRB_name: GRB220521A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32089
SUBJECT: GRB 220521A: Fermi GBM detection
DATE:    22/05/22 15:25:46 GMT
FROM:    Suraj Poolakkil at UAH  <sp0076@uah.edu>

S. Poolakkil (UAH) and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 23:20:21.73 UT on 21 May 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220521A (trigger 674868026 / 220521972)
which was also detected by the Swift/BAT (Dichiara et al. 2022, GCN 32076).
The Fermi GBM Final Real-time Localization (GCN 32075) is consistent with
the Swift/BAT position.

The angle from the Fermi LAT boresight at the GBM trigger time is 105
degrees.

The GBM light curve consists of multiple peaks followed
by some extended emission with a duration (T90) of about 14 s (50-300 keV).
The time-averaged spectrum from T0-1.024 s to T0+3.072 s
is best fit by a power law function with an exponential
high-energy cutoff. The power law index is -1.51 +/- 0.23  and
the cutoff energy, parameterized as Epeak, is 37 +/- 7 keV.

The event fluence (10-1000 keV) in this time interval is
(6.62 +/- 0.49)E-07 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.32 s in the 10-1000 keV band
is 6.3 +/- 0.4 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: GRB220521A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32090
SUBJECT: GRB 220521A: Swift-BAT refined analysis
DATE:    22/05/22 16:41:20 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

A. Y. Lien (U Tampa), S. D. Barthelmy (GSFC),
S. Dichiara (PSU), H. A. Krimm (NSF),
S. Laha (GSFC/UMBC), 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-240 to T+962 sec from the recent telemetry
downlink, we report further analysis of BAT GRB 220521A (trigger #1107466)
(Dichiara et al., GCN Circ. 32076).  The BAT ground-calculated position is
RA, Dec = 275.218, 10.372 deg which is
   RA(J2000)  =  18h 20m 52.3s
   Dec(J2000) = +10d 22' 20.0"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 46%.

The mask-weighted light curve shows a multi-peaked structure that
starts at ~T0 and ends at ~T+16 s. The two main peaks occur at ~T+0.5 s
and ~T+10 s, respectively. T90 (15-350 keV) is 13.55 +- 2.69 sec (estimated
error including systematics).

The time-averaged spectrum from T-0.23 to T+16.17 sec is best fit by
a simple power-law model.  The power law index of the time-averaged
spectrum is 1.97 +- 0.18.  The fluence in the 15-150 keV band
is 8.1 +- 0.8 x 10^-7 erg/cm2. The 1-sec peak photon flux measured
from T-0.18 sec in the 15-150 keV band is 4.7 +- 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/1107466/BA/


GRB_name: GRB220521A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32091
SUBJECT: GRB 220521A: LCO Optical Detection
DATE:    22/05/22 20:52:33 GMT
FROM:    Robert Strausbaugh at U. of the Virgin Islands  <robert.strausbaugh@uvi.edu>

R. Strausbaugh (U. of the Virgin Islands), A. Cucchiara (College of Marin) report on behalf of a larger collaboration:

We observed GRB 220521A (Dicharia et al., GCN 32076; Fermi GBM Team, GCN 32075) with the LCO 1-m Sinistro instrument at the Teide Observatory, Tenerife site, on May 22, from 00:04 to 00:32 UT (corresponding to 0.73 to 1.20 hours from the GRB trigger time) with the Bessel R and I filters.

We performed a series of 3x300s exposures in R and I bands. We detect an optical counterpart at the NOT optical afterglow location (Malesani et al., 32078 GCN 32078) that is consistent with other optical detections (Malesani et al., GCN 32078; Fynbo et al., GCN 32079; Goranskij et al., GCN 32082). The following magnitudes are calculated using the USNO-B.1 catalog as reference:

R=21.57+/-0.23
I=18.61+/-0.63

These magnitudes are not corrected for galactic extinction.

R.S. is funded by NSF AST grant #1831682


GRB_name: GRB220523A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32092
SUBJECT: GRB 220523A: Fermi GBM Final Real-time Localization
DATE:    22/05/23 04:21:51 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 04:11:29 UT on 23 May 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220523A (trigger 674971894.896998 / 220523175).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 136.7, Dec = -37.5 (J2000 degrees, equivalent to J2000 09h 06m, -37d 30'), with a statistical uncertainty of 8.3 degrees.

The angle from the Fermi LAT boresight is 64.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220523175/quicklook/glg_skymap_all_bn220523175.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220523175/quicklook/glg_healpix_all_bn220523175.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220523175/quicklook/glg_lc_medres34_bn220523175.gif


GRB_name: GRB220523A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32093
SUBJECT: Fermi GRB 220523A: Global MASTER-Net observations report 
DATE:    22/05/23 04:45:21 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-OAGH robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) started inspect of the Fermi GRB 220523A ( Fermi GBM team, GCN 32092) errorbox  293 sec after notice time and 330 sec after trigger time at 2022-05-23 04:17:00 UT, with upper limit up to  13.7 mag. The observations began at zenith distance = 81 deg. The sun  altitude  is -23.0 deg. 

MASTER-OAFA robotic telescope  located in Argentina (OAFA observatory of San Juan National University) started inspect of the Fermi GRB 220523A errorbox  1093 sec after notice time and 1130 sec after trigger time at 2022-05-23 04:30:20 UT, with upper limit up to  16.4 mag. The observations began at zenith distance = 82 deg. The sun  altitude  is -79.5 deg. 

The galactic latitude b =  7 deg., longitude l = 262 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1981570

We obtain a following upper limits.  

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

     361 | 2022-05-23 04:17:00 |         MASTER-OAGH | (09h 03m 15.41s , -27d 18m 29.2s) |   C |    60 | 13.0 |        
     467 | 2022-05-23 04:18:46 |         MASTER-OAGH | (09h 12m 12.12s , -27d 17m 32.7s) |   C |    60 | 13.3 |        
    1161 | 2022-05-23 04:30:20 |         MASTER-OAFA | (09h 03m 53.93s , -36d 01m 09.5s) |   C |    60 | 16.3 |        
    1252 | 2022-05-23 04:31:52 |         MASTER-OAFA | (09h 13m 51.60s , -35d 59m 56.3s) |   C |    60 | 16.4 |        
    1443 | 2022-05-23 04:35:02 |         MASTER-OAGH | (09h 40m 56.38s , -30d 37m 34.2s) |   C |    60 | 13.7 |        
Filter C is a clear (unfiltred) band. 


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


GRB_name: GRB220514A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32095
SUBJECT: GRB 220514A: Swift/BAT-GUANO detection outside the coded FOV
DATE:    22/05/23 18:28:42 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>

Aaron Tohuvavohu (U Toronto), Gayathri Raman (PSU), James DeLaunay
(UAlabama), Jamie A. Kennea (PSU), report:

Swift/BAT did not localize GRB 220514A onboard (T0:
2022-05-14T12:24:32 UTC, Fermi/GBM GCN 32038, INTEGRAL GCN 32041,
AstroSat GCN 32070, GECAM detection).

The Fermi, INTEGRAL, 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,
arXiv:2111.01769), detects the burst with a sqrt(TS) of 24.9 in a
16.384 s analysis time bin.
The burst episode as seen by BAT is >50 s long.

NITRATES results indicate a burst coming from outside the coded FoV,
with DeltaLLHOut of -29.7. The most likely sky position from NITRATES
agrees well with the INTEGRAL/IBAS position (GCN 32041).

See Section 9.1 and Figure 20 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: GRB220521A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32096
SUBJECT: GRB 220521A: REM optical/NIR upper limits
DATE:    22/05/23 20:14:11 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <pda.davanzo@gmail.com>

M. Ferro, R. Brivio, A. Melandri, P. D'Avanzo, S. Covino, D. Fugazza, (INAF-OAB) on behalf of the REM team, report:

We observed the field of GRB 220521A (Fermi/GBM team GCN Circ. 32075; Dichiara et al., GCN Circ. 32076) with 
the REM 60cm robotic telescope  located at the ESO premise of La Silla (Chile). The observations were carried in the 
g, r, i, z, J, H and K bands, starting on 2022 May 22 at 02:24:40 UT (i.e. about 3.1 hours after the burst) and lasting for 
about one hour. 

The optical afterglow (Malesani et al., GCN Circ. 32078) is not detected. From preliminary photometry we derive the 
following magnitude upper limits (3sigma c.l.): 

g > 19.5
r > 19.1
i > 18.8
z > 17.4
(AB; calibrated against the Pan-STARRS catalogue) at a mid time of t-t0 ~ 3.5 hours;

J > 16.6
H > 16.2
K > 13.5
(Vega; calibrated against the 2MASS catalogue) at a mid time of t-t0 ~ 3.9 hours.


GRB_name: GRB220521A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32097
SUBJECT: GRB 220521A: MMT Afterglow Imaging
DATE:    22/05/23 20:22:56 GMT
FROM:    Jillian Rastinejad at Northwestern Univ.  <jillianrastinejad2024@u.northwestern.edu>

J. Rastinejad, W. Fong (Northwestern), D. B. Malesani (Radboud Univ. and DAWN/NBI), A. Cucchiara (College of Marin/UVI), and G. Schroeder (Northwestern) report:

''We observed the location of the Fermi and Swift GRB 220521A (Fermi GBM team, GCN 32075, Dichiara et al., GCN 32076; Poolakkil & Meegan, GCN 32089, Strausbaugh et al. GCN 32091) with the Binospec imager and spectrograph mounted on the MMT 6.5-meter telescope on Mount Hopkins, Arizona. We obtain 15x100 s imaging in the z-band at a mid-time of 2022 May 23.423 (1.45 days post-burst) at an average airmass of 1.08. We detect a source at the position of the afterglow reported by Malesani & Pursimo (GCN 32078). Calibrated to PS1, we measure z = 24.04 +/- 0.16 mag (AB system and not corrected for Galactic extinction in the direction of the burst). 

We thank Ryan Howie and Ben Weiner at the MMT for the rapid scheduling and execution of these observations.''


GRB_name: GRB220523B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32098
SUBJECT: GRB 220523B: Fermi GBM detection
DATE:    22/05/23 20:34:32 GMT
FROM:    Cori Fletcher at USRA  <cfletcher@usra.edu>

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

At 13:24:08.42 UT on 23 May 2022, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 220523B (trigger 675005053 / 220523558).

The on-ground calculated location, using the Fermi GBM trigger data, is
RA = 104.31, Dec = 59.72 (J2000 degrees, equivalent to J2000 06h 57m, 59d 43'),
with a statistical uncertainty of 1.9 degrees.

The angle from the Fermi LAT boresight is 124 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220523558/quicklook/glg_skymap_all_bn220523558.png

The HEALPix FITS file, including the estimated localization systematic, can
be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220523558/quicklook/glg_healpix_all_bn220523558.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220523558/quicklook/glg_lc_medres34_bn220523558.gif


GRB_name: GRB220521A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32099
SUBJECT: GRB 220521A: Gemini Observations
DATE:    22/05/23 23:35:25 GMT
FROM:    Robert Strausbaugh at U. of the Virgin Islands  <robert.strausbaugh@uvi.edu>

 A. Cucchiara (College of Marin), R. Strausbaugh (U. of the Virgin Islands), J. Rastinejad, A. Nugent, W. Fong (Northwestern), D. B. Malesani (Radboud Univ. and DAWN/NBI) report on behalf of a larger collaboration:

On May 22.16 UT (T0+4.5 hr after the GRB) we observed the afterglow, of GRB 220521A (Fermi GBM team, GCN 32075; Dichiara et al., GCN 32076; Poolakkil & Meegan, GCN 32089; Strausbaugh et al., GCN 32091) with the Gemini-South telescope and the GMOS camera.

We performed a series of spectroscopic observations with the R400 grating centered at 7500 AA (2x600 s) and 8100 AA (2x600 s). Observations were obtained at an average airmass of 2.34.  In our 300 s, z-band acquisition image we detected the GRB counterpart at the NOT optical afterglow location (Malesani et al., GCN 32078).

In our preliminary analysis we measured z (AB)=20.9 +/- 0.3, calibrated against 10 PS1 stars. No extinction correction has been applied.

Our visual inspection of the spectroscopic data confirms the redshift reported by Fynbo et al. (GCN 32079) as z=5.57 based on the detection of Lyman alpha, SiIV and Ni lines.

Combined with the results from MMT (Rastinejad et al., GCN 32097)we derive a decay index in z-band of alpha=1.57, consistent with the current X-ray behavior  (Tohuvavohu et al., GCN 32086). Further analysis is in progress.

We thank the Gemini-S staff, particularly Javier Fuentes and Veronica Firpo, for conducting these observations.


GRB_name: GRB220523B
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32100
SUBJECT: Fermi GRB 220523B: Global MASTER-Net observations report 
DATE:    22/05/24 03:30:25 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-OAGH robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) started inspect of the Fermi GRB 220523B ( Fermi GBM team, GCN 32098) errorbox  24684 sec after notice time and 49281 sec after trigger time at 2022-05-24 03:05:29 UT, with upper limit up to  18.6 mag. Observations started at twilight.  The observations began at zenith distance = 55 deg. The sun  altitude  is -10.8 deg. 

The galactic latitude b = 24 deg., longitude l = 157 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1982098

We obtain a following upper limits.  

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

   49311 | 2022-05-24 03:05:29 |         MASTER-OAGH | (06h 58m 44.58s , +60d 04m 50.9s) |   C |    60 | 16.7 |        
   49311 | 2022-05-24 03:05:29 |         MASTER-OAGH | (06h 58m 01.41s , +60d 31m 19.2s) |   C |    60 | 16.8 |        
   49393 | 2022-05-24 03:06:51 |         MASTER-OAGH | (07h 14m 39.16s , +60d 03m 59.7s) |   C |    60 | 16.3 |        
   49393 | 2022-05-24 03:06:51 |         MASTER-OAGH | (07h 13m 57.92s , +60d 30m 10.4s) |   C |    60 | 16.5 |        
   49474 | 2022-05-24 03:08:12 |         MASTER-OAGH | (07h 04m 54.62s , +58d 11m 27.1s) |   C |    60 | 16.9 |        
   49474 | 2022-05-24 03:08:12 |         MASTER-OAGH | (07h 04m 14.95s , +58d 37m 55.5s) |   C |    60 | 17.1 |        
   49555 | 2022-05-24 03:09:33 |         MASTER-OAGH | (07h 20m 03.85s , +58d 10m 26.5s) |   C |    60 | 16.4 |        
   49555 | 2022-05-24 03:09:33 |         MASTER-OAGH | (07h 19m 25.49s , +58d 36m 42.1s) |   C |    60 | 16.8 |        
   49636 | 2022-05-24 03:10:54 |         MASTER-OAGH | (06h 35m 23.03s , +58d 37m 28.8s) |   C |    60 | 16.6 |        
   49636 | 2022-05-24 03:10:54 |         MASTER-OAGH | (06h 36m 03.81s , +58d 10m 34.2s) |   C |    60 | 16.6 |        
   49717 | 2022-05-24 03:12:15 |         MASTER-OAGH | (06h 51m 13.84s , +58d 11m 35.9s) |   C |    60 | 17.2 |        
   49717 | 2022-05-24 03:12:15 |         MASTER-OAGH | (06h 50m 34.20s , +58d 38m 21.7s) |   C |    60 | 17.3 |        
   49798 | 2022-05-24 03:13:36 |         MASTER-OAGH | (06h 51m 22.57s , +62d 24m 10.9s) |   C |    60 | 17.1 |        
   49798 | 2022-05-24 03:13:36 |         MASTER-OAGH | (06h 52m 07.32s , +61d 57m 32.8s) |   C |    60 | 16.8 |        
   49880 | 2022-05-24 03:14:58 |         MASTER-OAGH | (07h 09m 14.35s , +61d 58m 14.0s) |   C |    60 | 17.7 |        
   49880 | 2022-05-24 03:14:58 |         MASTER-OAGH | (07h 08m 30.60s , +62d 24m 31.6s) |   C |    60 | 17.7 |        
   49961 | 2022-05-24 03:16:19 |         MASTER-OAGH | (06h 28m 14.56s , +60d 03m 43.4s) |   C |    60 | 17.2 |        
   49961 | 2022-05-24 03:16:19 |         MASTER-OAGH | (06h 27m 30.84s , +60d 30m 44.1s) |   C |    60 | 17.3 |        
   50042 | 2022-05-24 03:17:40 |         MASTER-OAGH | (06h 44m 18.32s , +60d 05m 14.0s) |   C |    60 | 18.5 |        
   50042 | 2022-05-24 03:17:40 |         MASTER-OAGH | (06h 43m 35.60s , +60d 32m 05.3s) |   C |    60 | 18.1 |        
   50123 | 2022-05-24 03:19:01 |         MASTER-OAGH | (06h 43m 33.20s , +56d 17m 30.6s) |   C |    60 | 17.6 |        
   50123 | 2022-05-24 03:19:01 |         MASTER-OAGH | (06h 42m 54.88s , +56d 44m 30.3s) |   C |    60 | 17.7 |        
   50204 | 2022-05-24 03:20:22 |         MASTER-OAGH | (06h 58m 01.43s , +56d 16m 32.2s) |   C |    60 | 18.6 |        
   50204 | 2022-05-24 03:20:22 |         MASTER-OAGH | (06h 57m 24.05s , +56d 43m 24.8s) |   C |    60 | 18.2 |        
   50286 | 2022-05-24 03:21:44 |         MASTER-OAGH | (06h 58m 37.17s , +60d 03m 29.1s) |   C |    60 | 18.3 |        
   50286 | 2022-05-24 03:21:44 |         MASTER-OAGH | (06h 57m 55.35s , +60d 30m 14.7s) |   C |    60 | 18.2 |        
   50368 | 2022-05-24 03:23:06 |         MASTER-OAGH | (07h 14m 04.76s , +60d 30m 21.3s) |   C |    60 | 18.3 |        
   50368 | 2022-05-24 03:23:06 |         MASTER-OAGH | (07h 14m 45.72s , +60d 03m 52.5s) |   C |    60 | 18.2 |        
   50449 | 2022-05-24 03:24:27 |         MASTER-OAGH | (07h 04m 55.07s , +58d 11m 28.5s) |   C |    60 | 18.5 |        
   50449 | 2022-05-24 03:24:27 |         MASTER-OAGH | (07h 04m 15.84s , +58d 38m 09.6s) |   C |    60 | 18.4 |        
Filter C is a clear (unfiltred) band. 


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


GRB_name: GRB220521A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32101
SUBJECT: GRB 220521A: MITSuME Akeno optical upper limits
DATE:    22/05/24 09:32:51 GMT
FROM:    Naohiro Ito at Tokyo Tech  <n.ito@hp.phys.titech.ac.jp>

S. Sato, M. Sasada, K. L. Murata, R. Hosokawa, Y. Imai, N. Ito, M. Niwano,
Y. Takamatsu, M. Tateda, T. Hattori, Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We observed the field of GRB 220521A (The Fermi GBM team GCN Circular
#32075, Dichiara et al. GCN Circular #32076, Evans et al. GCN Circular
#32077, Malesani and Pursimo et al. GCN Circular #32078, Fynboet al. GCN
Circular #32079, Evans et al. GCN Circular #32081, Goranskij et al. GCN
Circular #32082, Kuin and Dichiara GCN Circular #32085, Tohuvavohu et al.
GCN Circular #32086, Watson et al. GCN Circular #32087, Nazarov et al. GCN
Circular #32088, Poolakkil and Meegan GCN Circular #32089, Lien et al. GCN
Circular #32090, Strausbaugh et al. GCN Circular #32091) with the optical
three color (g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm
telescope Akeno.

The observation with a series of 60 sec exposures started at 2022-05-22
11:56:05 UT (12.6 hours after the Fermi/GBM trigger). We stacked the images
with good conditions. We did not detect the optical afterglow (Malesani et
al. GCN Circular #32078, Goranskij et al. GCN Circular #32082, Strausbaugh
et al. GCN Circular #32091, Rastinejad et al. GCN Circular #32097,
Cucchiara et al. GCN Circular #32099). We obtained the 5-sigma limits of
the stacked images as follows.

T0+[hour] | MID-UT | T-EXP[sec] | 5-sigma limits
------------------------------------------------------------------------------------------------
16.6 | 2022-05-22 15:56:34 | 6780 | g' > 19.3, Rc > 19.1, Ic > 18.6
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time

We used PS1 catalog for flux calibration. The magnitudes are expressed in
the AB system. The images were processed in real-time through the MITSuME
GPU reduction pipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 1, Pages
4-24; https://github.com/MNiwano/Eclaire).


GRB_name: GRB220521A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32103
SUBJECT: GRB 220521A: ISON-Castelgrande observatory optical observations
DATE:    22/05/24 13:31:23 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Belkin (IKI, HSE), A. Pozanenko (IKI), S. Schmalz (KIAM RAS), A. 
Schmalz (KIAM RAS),  N. Pankov (HSE), Filippo Graziani (GAUSS Srl), 
Riccardo Di Roberto (GAUSS Srl)  report on behalf of IKI GRB FuN:

We observed  the GRB 220521A (Fermi GBM Team, GCN 32075; Dichiara et 
al., GCN 32076;  Poolakkil and Meegan, GCN 32089) with ORI-22 telescope 
of ISON-Castelgrande observatory. Observation started on 2022-05-21 (UT) 
23:25:00, i.e. 4.65 min after GRB trigger. The series consists of 60 
images with an exposure of 60 s in a Clear filter.

The optical afterglow (Malesani et al., GCN 32078; Fynbo et al., GCN 
32079; Goranskij et al., GCN 32082; Strausbaugh et al., GCN 32091; 
Rastinejad et al., GCN 32097) is not detected in the initial part of the 
series and is marginally detected in the stacked image of the second 
part of the series.

Preliminary photometry of the stacked images is following

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

2022-05-21 23:25:00   0.012951  Clear 28*60    n/d   n/d   20.5
2022-05-21 23:57:00   0.035868  Clear 30*60    20.3  0.4   20.2


The photometry is based on nearby USNO-B1.0 (R2) stars
RA DEC R2
18:21:04.76880 +10:21:04.7232 16.26
18:21:07.39800 +10:20:37.5000 16.73


GRB_name: GRB220521B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32104
SUBJECT: IPN triangulation of GRB 220521B
DATE:    22/05/24 14:54:42 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 HEND/Mars-Odyssey team,

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

A long-duration GRB 220521B
has been detected by Konus-Wind, INTEGRAL (SPI-ACS),
and Mars-Odyssey (HEND), so far, at about 54210 s UT (15:03:30).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
 ---------------------------------------------
  RA(2000), deg                 Dec(2000), deg
 ---------------------------------------------
 Center:
   55.464 (03h 41m 51s) +38.990 (+38d 59' 25")
 Corners:
   57.749 (03h 51m 00s) +34.608 (+34d 36' 29")
   52.895 (03h 31m 35s) +43.109 (+43d 06' 34")
   52.823 (03h 31m 18s) +43.047 (+43d 02' 49")
   57.684 (03h 50m 44s) +34.535 (+34d 32' 05")
 ---------------------------------------------
The error box area is 2520 sq. arcmin, and its maximum
dimension is 9.3 deg (the minimum one is 5 arcmin).
The Sun distance was 14 deg.

This box may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220521_T54209/IPN/

The time history and spectrum will be given in forthcoming GCN Circulars.


GRB_name: GRB220521A
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32105
SUBJECT: GRB 220521A: classification and detection by SPI-ACS/INTEGRAL
DATE:    22/05/24 14:55:52 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

P. Minaev (IKI), A. Pozanenko (IKI), G. Mozgunov (MIPT, IKI) report on 
behalf of GRB IKI FuN:

We analyzed GRB 220521A till now detected by Swift and GBM/Fermi (Fermi 
GBM Team, GCN 32075; Dichiara et al., GCN 32076;  Poolakkil and Meegan, 
GCN 32089) using publicly available data of GBM/Fermi and 
SPI-ACS/INTEGRAL. Using GBM/Fermi data we estimated the duration of T_90 
= 12.0 +/- 0.5 s in 7 - 100 keV energy band and performed spectral 
analysis in the time interval of (-1, 12) s. The best fit is obtained 
for CPL model with following parameters: E_p = 62 (-15, +68) keV, alpha 
= -1.5 +/- 0.4. The fluence of F = (9.8 +/- 1.2)E-7 erg/cm**2 is 
obtained in 10 - 1000 keV energy band. The parameters are close to those 
reported in (Poolakkil and Meegan, GCN 32089).
Using redshift of z = 5.6 (Fynbo et al., GCN 32079; Cucchiara et al., 
GCN 32099) we obtain E_iso = (6.2 Â± 0.8)E52 erg in 1-10000 keV energy 
range. Using T_90,i - EH diagram [1,2] we classify the burst as type II 
(long burst) for any possible redshift greater than z = 0.07. T_90,i - 
EH diagram can be found in
http://grb.rssi.ru/GRB220521A/GRB220521A_EHD.png

The burst was also detected by SPI-ACS/INTEGRAL with total statistical 
significance of 5.8 sigma. The angle to the SPI-ACS axis is 47 degrees. 
Comparing fluences of long-duration GRBs registered by both SPI-ACS and 
GBM/Fermi (Chelovekov et al., in preparation) we estimated the GRB 
220521A fluence to be 1.1E-6 erg/cm**2 in the 10-1000 keV energy band 
(the 95% confidence region 3.4E-7 â€“ 4.1E-6 erg/cm**2, incl. 
systematics). Light curves based on GBM/Fermi and SPI-ACS/INTEGRAL data 
can be found in
http://grb.rssi.ru/GRB220521A/GRB220521A_light_curves.png

[1] - Minaev et al., MNRAS, 492, 1919, 2020
[2] - Minaev et al., Astronomy Letters, 46, 9, 573, 2020


GRB_name: GRB220521B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32106
SUBJECT: Konus-Wind detection of GRB 220521B
DATE:    22/05/24 14:58:31 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 220521B
(IPN triangulation: Kozyrev at al., GCN Circ. 32104)
triggered Konus-Wind at T0=54209.631 s UT (15:03:29.631).

The burst light curve shows a single emission pulse,
which starts at ~T0-0.4 s and has a total duration of ~2.3 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/GRB220521_T54209/

As observed by Konus-Wind, the burst
had a fluence of 3.99(-0.43,+0.50)x10^-6 erg/cm2,
and a 64-ms peak flux, measured from T0+0.038 s,
of 5.03(-2.05,+2.89)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 - 4 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.66(-0.35,+0.41)
and Ep = 153(-21,+29) keV (chi2 = 91/78 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 = 91/77 dof).

The spectrum near the peak energy flux
(measured from T0 to T0+0.256 s)
is best fit in the 20 keV - 4 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -0.84(-0.39,+0.52)
and Ep = 585(-232,+646) keV (chi2 = 43/31 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -1.6
(chi2 = 43/30 dof).

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


GRB_name: GRB220521A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32107
SUBJECT: GRB 220521A: BOOTES-2/TELMA and CAHA 2.2m telescope optical upper limit
DATE:    22/05/24 15:14:20 GMT
FROM:    Youdong HU at IAA-CSIC  <huyoudong072@hotmail.com>

Y.-D. Hu, E. Fernandez-Garcia, T.-R. Sun, A. J. Castro-Tirado, M.D. Caballero-Garcia, R. Sanchez-Ramirez, I. Perez-Garcia (IAA-CSIC), I. Vico, S. Cikota (CAHA), C. Perez del Pulgar, A. Castellon, M. A. Castro Tirado (Univ. de Malaga), R. Fernandez-Munoz (IHSM/UMA-CSIC) and M. Jelinek (ASU-CAS), on behalf of a larger collaboration, report:

Following the detection of GRB 220521A by Fermi (GBM team GCNC 32075) and Swift (Dichiara et al. GCNC 32076), the 0.6m BOOTES-2/TELMA robotic telescope in Algarrobo Costa (Malaga, Spain) automatically respond to this event and pointed to the Swift/XRT position (Evans et al. GCNC 32077) on May 21, 23:20:56 UT (35 s post trigger). Due to the cloudy weather, only useful frames were obtained starting at 23:39:23 UT (i.e. ~19 min after trigger). The afterglow detected by both XRT and NOT is not detected in our co-added image (60 x 23 s, clear filter), down to 18.4 mag.

Later on, we also triggered the 2.2m CAHA telescope (+ CAFOS) at the Calar Alto Observatory (Almeria, Spain). Images (Sloan i-band) were gathered since May. 23 01:36 UT (i.e. 1.1 day post trigger). On the co-added image (14 x 180 s), the afterglow is not detected down to i = 24.1 mag.

Those non-detections are consistent with the previous reports from NOT (Malesani et al. GCNC 32078, Fynbo et al. GCNC 32079), SAO (Goranskij et al. GCNC 32082), RATIR (Watson et al. GCNC 32087), Sintesz-Newton (Nazarov et al. GCNC 32088), LCO (Strausbaugh et al. GCNC 32091), REM (Ferro et al. GCNC 32096), MMT (Rastinejad et al. GCNC 32097), Gemini (Cucchiara et al. GCNC 32099), MITSuME (Sato et al. GCNC 32101) and ISON-Castelgrande (Belkin et al. GCNC 32103).

We thank the staff at IHSM/UMA-CSIC La Mayora and CAHA for their excellent support.


GRB_name: GRB220522B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32108
SUBJECT: IPN triangulation of GRB 220522B
DATE:    22/05/24 18:37:10 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,

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 220522B
was detected by Konus-Wind, INTEGRAL (SPI-ACS),
and Mars-Odyssey (HEND) at about 1058 s UT (00:17:38).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
    43.717 (02h 54m 52s)  -3.789 ( -3d 47' 19")
  Corners:
    43.363 (02h 53m 27s)  -9.058 ( -9d 03' 28")
    43.540 (02h 54m 10s)  -9.308 ( -9d 18' 30")
    43.256 (02h 53m 01s)  +4.344 ( +4d 20' 39")
    42.925 (02h 51m 42s)  +5.219 ( +5d 13' 08")
  ---------------------------------------------
The error box area is 2.77 sq. deg, and its maximum
dimension is 14.54 deg (the minimum one is 11.88 arcmin).
The Sun distance was 22 deg.

This box may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220522_T01058/IPN/

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


GRB_name: GRB220522B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32109
SUBJECT: Konus-Wind detection of GRB 220522B
DATE:    22/05/24 20:26:44 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 220522B
(IPN triangulation: Kozyrev at al., GCN Circ. 32108)
triggered Konus-Wind at T0=1058.258 s UT (00:17:38.258).

The burst light curve shows a multipeaked structure
which starts at ~T0-4.4 s and has a total duration of ~106.3 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/GRB220522_T01058/

As observed by Konus-Wind, the burst
had a fluence of 5.49(-1.66,+1.13)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+9.344 s,
of 5.76(-2.35,+2.67)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+41.216 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 = -0.47(-0.53,+0.56),
the high energy photon index beta = -1.94(-0.86,+0.15),
the peak energy Ep = 230(-60,+197) keV
(chi2 = 85/67 dof).

The spectrum near the maximum count rate
(measured from T0+8.448 to T0+16.640 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 = -0.37(-0.48,+0.94),
the high energy photon index beta = -2.18(-0.90,+0.28),
the peak energy Ep = 224(-72,+108) keV
(chi2 = 73/66 dof).

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


GRB_name: GRB220521A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32110
SUBJECT: GRB 220521A: ALMA detection
DATE:    22/05/24 21:30:44 GMT
FROM:    Tanmoy Laskar at U of Bath  <tanmoylaskar@gmail.com>

T. Laskar (University of Bath), S. Bhandari (ASTRON/JIVE), K. D. Alexander
(Northwestern), R. Margutti (Berkeley), E. Berger (Harvard), W. Fong
(Northwestern), R. Chornock (Berkeley), C. G. Mundell (University of Bath),
and P. Schady (University of Bath) report on behalf of a larger
collaboration:

"We observed GRB 220521A (Dichiara et al., GCN 32076) with the Atacama
Large Millimeter/Submillimeter Array (ALMA) at 97.5 GHz beginning on 2022
May 23 05:30 UT (1.26 days after the burst).

Preliminary analysis reveals a millimeter source with flux density of ~ 0.3
mJy at position:

RA (J2000) = 18:20:55.12 (+/- 0.03")
Dec (J2000) = 10:22:20.52 (+/- 0.03")

consistent with the X-ray position (Evans et al., GCN 32077) and optical
position (Malesani et al., GCN 32078).

We thank the JAO staff, AoD, P2G, and the entire ALMA team for their help
with these observations."


GRB_name: GRB220521A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32111
SUBJECT: GRB 220521A: ATCA detection
DATE:    22/05/24 21:37:04 GMT
FROM:    Tanmoy Laskar at U of Bath  <tanmoylaskar@gmail.com>

T. Laskar (University of Bath), S. Bhandari (ASTRON/JIVE), K. D. Alexander
(Northwestern), E. Berger (Harvard), R. Chornock (UC Berkeley), D.
Coppejans (Northwestern), M. Drout (U. Toronto), H. van Eerten (University
of Bath), W. Fong (Northwestern), C. Guidorzi (U. Ferrara), R. Margutti (UC
Berkeley), C. G. Mundell (University of Bath), P. Schady (University of
Bath), and G. Schroeder (Northwestern) report:

"We observed GRB 220521A (Dichiara et al., GCN 32076) with the Australia
Telescope Compact Array (ATCA) at 39 GHz beginning on 2022 May 24 14:44 UT.
We detect a radio counterpart at a position consistent with the X-ray
position (Evans et al., GCN 32077), optical position (Malesani et al., GCN
32078), and mm-band position (Laskar et al., GCN 32110) with a preliminary
flux density of ~ 0.2 mJy at a mid-time of 2.4 days after the burst.

We thank the CSIRO staff for approving and scheduling these observations.

The Australia Telescope Compact Array 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: GRB220525A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32112
SUBJECT: GRB 220525A: Fermi GBM Final Real-time Localization
DATE:    22/05/25 00:21:19 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 00:10:54 UT on 25 May 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220525A (trigger 675130259.241452 / 220525008).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 14.9, Dec = 18.3 (J2000 degrees, equivalent to J2000 00h 59m, 18d 18'), with a statistical uncertainty of 1.2 degrees.

The angle from the Fermi LAT boresight is 58.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220525008/quicklook/glg_skymap_all_bn220525008.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220525008/quicklook/glg_healpix_all_bn220525008.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220525008/quicklook/glg_lc_medres34_bn220525008.gif


GRB_name: GRB220525A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32113
SUBJECT: GRB 220525A: BALROG localization (Fermi Trigger 675130259 / GRB 220525008)
DATE:    22/05/25 00:32:54 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
675130259 at 00:10:54 on 25 May. 2022 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) = 10.61+/-1.03 deg
Decl.(2000.0) = 15.31+/-0.70 deg
We estimate an additional systematic error of 1 deg.

Further details are available at:
https://grb.mpe.mpg.de/grb/GRB220525008/

The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB220525008/healpix

The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB220525008/json    


GRB_name: GRB220524A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32115
SUBJECT: IPN triangulation of GRB 220524A
DATE:    22/05/25 19:42:10 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 HEND/Mars-Odyssey team,

A. Ridnaia, D. Frederiks, D. Svinkin, A. Lysenko,
and T. Cline on behalf of the Konus-Wind 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 long-duration GRB 220524A
has been detected by Konus-Wind, INTEGRAL (SPI-ACS),
Swift (BAT), and Mars-Odyssey (HEND),
so far, at about 35587 s UT (09:53:07).
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:
   20.862 (01h 23m 27s) +46.592 (+46d 35' 30")
 Corners:
   21.916 (01h 27m 40s) +46.226 (+46d 13' 34")
   19.808 (01h 19m 14s) +47.018 (+47d 01' 03")
   19.794 (01h 19m 10s) +46.938 (+46d 56' 16")
   21.899 (01h 27m 36s) +46.146 (+46d 08' 45")
 ---------------------------------------------
The error box area is 447 sq. arcmin, and its maximum
dimension is 1.68 deg (the minimum one is 4.6 arcmin).
The Sun distance was 41 deg.

This box may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220524_T35587/IPN/

The time history and spectrum will be given in forthcoming GCN Circulars.


GRB_name: GRB220524B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32117
SUBJECT: IPN triangulation of GRB 220524B
DATE:    22/05/25 21:42:09 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,

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 220524B
was detected by Konus-Wind, INTEGRAL (SPI-ACS),
and Mars-Odyssey (HEND) at about 57898 s UT (16:04:58).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
    70.274 (04h 41m 06s) -19.486 (-19d 29' 11")
  Corners:
    70.075 (04h 40m 18s) -21.168 (-21d 10' 04")
    70.146 (04h 40m 35s) -21.193 (-21d 11' 34")
    70.452 (04h 41m 49s) -17.794 (-17d 47' 37")
    70.382 (04h 41m 32s) -17.767 (-17d 46' 01")
  ---------------------------------------------
The error box area is 840 sq. arcmin, and its maximum
dimension is 3.43 deg (the minimum one is 4.1 arcmin).
The Sun distance was 40 deg.

This box may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220524_T57898/IPN

The time history and spectrum will be given in forthcoming GCN Circulars.


GRB_name: GRB220525A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32118
SUBJECT: IPN triangulation of GRB 220525A
DATE:    22/05/25 21:48:51 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, and C. Wilson-Hodge
on behalf of the Fermi GBM 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 220525A
(Fermi GBM detection: Fermi GBM Team, GCN Circ 32112;
BALROG localization: Kunzweiler et al., GCN Circ 32113)
has been detected by Fermi (GBM trigger 675130259), CALET (CGBM),
Konus-Wind, and Mars-Odyssey (HEND), so far,
at about 654 s UT (00:10:54).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
    13.365 (00h 53m 28s) +16.396 (+16d 23' 46")
  Corners:
    17.561 (01h 10m 15s) +12.813 (+12d 48' 48")
     9.561 (00h 38m 15s) +18.778 (+18d 46' 42")
     9.753 (00h 39m 01s) +18.232 (+18d 13' 54")
    18.017 (01h 12m 04s) +11.551 (+11d 33' 04")
  ---------------------------------------------
The error box area is 4.2 sq. deg, and its maximum
dimension is 10.9 deg (the minimum one is 25 arcmin).
The Sun distance was 43 deg.

This box may be improved.

The IPN localization is consistent with, but reduces the area of, the
Fermi GBM Final Real-time position (GCN Circ. 32112) and BALROG
(GCN 32113) localizations.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220525_T00654/IPN/

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


GRB_name: GRB220525A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32119
SUBJECT: Fermi GRB 220525A: Global MASTER-Net observations report 
DATE:    22/05/26 11:15:29 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-OAGH robotic telescope  (Global MASTER-Net: http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L)  located in Mexico (OAGH National Institute for Astrophysics, Optics and Electronics) started inspect of the Fermi GRB 220525A ( Fermi GBM team, GCN 32112) errorbox  1 days 35557 sec after notice time and 1 days 35599 sec after trigger time at 2022-05-26 10:04:13 UT, with upper limit up to  17.2 mag. The observations began at zenith distance = 82 deg. The sun  altitude  is -24.1 deg. 

The galactic latitude b = -44 deg., longitude l = 126 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1984418

We obtain a following upper limits.  

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

  122089 | 2022-05-26 10:04:13 |         MASTER-OAGH | (00h 59m 08.17s , +16d 24m 55.4s) |   C |   180 | 15.5 |        
  122089 | 2022-05-26 10:04:13 |         MASTER-OAGH | (00h 59m 38.00s , +16d 01m 05.6s) |   C |   180 | 17.0 |        
  122701 | 2022-05-26 10:14:25 |         MASTER-OAGH | (00h 59m 06.62s , +16d 25m 33.8s) |   C |   180 | 16.1 |        
  122701 | 2022-05-26 10:14:25 |         MASTER-OAGH | (00h 59m 35.09s , +16d 00m 35.7s) |   C |   180 | 17.2 |        
Filter C is a clear (unfiltred) band. 


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


GRB_name: GRB220524A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32121
SUBJECT: Konus-Wind detection of GRB 220524A
DATE:    22/05/26 12:32:42 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The long GRB 220524A (IPN triangulation: Kozyrev et al., GCN 32115)
triggered Konus-Wind (KW) at T0=35587.191 s UT (09:53:07.191).

The burst light curve shows a multi-peaked structure,
which starts at ~T0-0.5 s and has a total duration of ~2.5 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/GRB220524_T35587/

As observed by Konus-Wind, the burst had
a fluence of (4.0 Â± 0.6)x10^-6 erg/cm^2 and
a 64-ms peak energy flux, measured from T0 + 2.048 s,
of (6.1 Â± 1.0)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).

A time-averaged spectrum of the burst (measured from T0 to T0+8.448 s)
is well fit in the 20 keV - 15 MeV range
by a power law with exponential cutoff (CPL) model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = -1.22(-0.23,+0.27) and Ep = 186(-38,+63) keV (chi2 = 93/98 dof).
Fitting this spectrum by a Band function yields the same values of alpha and Ep,
and an upper limit on the high energy photon index beta of -2.2 (chi2 = 92/97 dof).

All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.


GRB_name: GRB220525A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32122
SUBJECT: Konus-Wind detection of GRB 220525A
DATE:    22/05/26 12:36:42 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The long GRB 220525A (Fermi GBM detection: Fermi GBM Team, GCN 32112;
BALROG localization: Kunzweiler et al., GCN 32113;
IPN triangulation: Kozyrev et al., GCN 32118)
triggered Konus-Wind (KW) at T0=654.268 s UT (00:10:54.268).

The burst light curve shows a single multipeaked pulse,
which starts at ~T0-3 s and has a total duration of ~12 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/GRB220525_T00654/

As observed by Konus-Wind, the burst had
a fluence of (1.7 Â± 0.3)x10^-6 erg/cm^2 and
a 64-ms peak energy flux, measured from T0 + 2.624 s,
of (4.3 Â± 0.7)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+8.448 s)
is best fit in the 20 keV - 15 MeV range by
a Band function with the following model parameters:
the low-energy photon index alpha = -0.69 (-0.22,+0.26),
the high energy photon index beta = -3.0 (-7.0,+0.44),
the peak energy Ep = 190 (-22,+26) keV,
chi2 = 88/96 dof.

All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.


GRB_name: GRB220524B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32123
SUBJECT: Konus-Wind detection of GRB 220524B
DATE:    22/05/26 13:06:23 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

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

The long GRB 220524B (IPN triangulation: Kozyrev et al., GCN 32117)
triggered Konus-Wind (KW) at T0=57898.077 s UT (16:04:58.077).

The burst light curve shows two multipeaked pulses
in the interval from ~T0-3 s to ~T0+20 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/GRB220524_T57898/

As observed by Konus-Wind, the burst had
a fluence of (1.6 Â± 0.5)x10^-5 erg/cm^2 and
a 64-ms peak energy flux, measured from T0 + 16.576 s,
of (7.4 Â± 2.3)x10^-6 erg/cm^2/s (both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+24.832 s)
is best fit in the 20 keV - 15 MeV range by
a Band function with the following model parameters:
the low-energy photon index alpha = -1.31 (-0.26,+0.44),
the high energy photon index beta = -1.96 (-0.76,+0.21),
the peak energy Ep = 249 (-130,+380) keV,
chi2 = 94/97 dof.

All the quoted errors are estimated at the 90% confidence level.
All the presented results are preliminary.


GRB_name: GRB220523B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32124
SUBJECT: GRB 220523B: CALET Gamma-Ray Burst Monitor detection
DATE:    22/05/26 14:42:39 GMT
FROM:    Yuta Kawakubo at Louisiana State U./CALET  <kawakubo1@lsu.edu>

S. Sugita, A. Yoshida, T. Sakamoto(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 220523B (Fermi GBM Detection: Fermi GBM team,
GCN Circ. 32098) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 13:24:04.522 UTC on 23 May 2022
(http://cgbm.calet.jp/cgbm_trigger/flight/1337347281/index.html).
The burst signal was seen by all CGBM detectors.

The burst light curve shows a multi-peaked structure which starts
at T+3.1 sec, peaks at T+5.7 sec, and ends at T+10.1 sec.
The T90 and T50 durations measured by the SGM data are 5.9 +/- 0.5 sec
and 2.1 +/- 0.3 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1337347281/

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


GRB_name: GRB220525A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32125
SUBJECT: GRB 220525A: CALET Gamma-Ray Burst Monitor detection
DATE:    22/05/26 14:54:18 GMT
FROM:    Yuta Kawakubo at Louisiana State U./CALET  <kawakubo1@lsu.edu>

Y. Kawakubo (LSU), A. Yoshida, T. Sakamoto, S. Sugita (AGU),
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 220525A (Fermi GBM Final Real-time Localization: Fermi GBM team,
GCN Circ. 32112; BALROG localization: Kunzweiler et al., GCN Circ 32113; 
IPN triangulation: Kozyrev et al., GCN Circ 32118; Konus-Wind detection: 
Frederiks et al., GCN Circ 32122) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 00:10:52.713 UTC on 25 May 2022
(http://cgbm.calet.jp/cgbm_trigger/flight/1337472486/index.html).
The burst signal was seen by only SGM detector.

The burst light curve shows a double-peaked structure which starts
at T+1.6 sec, peaks at T+4.7 sec, and ends at T+8.7 sec.
The T90 and T50 durations measured by the SGM data are 6.0 +/- 0.4 sec
and 2.6 +/- 0.5 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1337472486/

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


GRB_name: GRB220525A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32127
SUBJECT: GRB 220525A: Fermi GBM Detection
DATE:    22/05/26 22:19:35 GMT
FROM:    Stephen Lesage at Fermi-GBM Team  <sjl0014@uah.edu>

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

"At 00:10:54 UT on 25 May 2022, the Fermi Gamma-ray Burst Monitor (GBM)
triggered and located GRB 220525A (trigger 675130259/220525008)
which was also detected by Konus-Wind (D. Frederiks et al. 2022, GCN 32122)
and CALET (Y. Kawakubo et al. 2022, GCN 32125) and localized by IPN
(Kozyrev et al. 2022, GCN 32118).
The Fermi GBM Final Real-time Localization (GCN 32112) is consistent
with the IPN triangulation.

The angle from the Fermi LAT boresight is 58 degrees.

The GBM light curve shows a single bright emission episode with a duration (T90)
of about 16.1 s (10-1000 keV). The time-averaged spectrum
from T0-10 to T0+15 s is best fit by
a power law function with an exponential high-energy cutoff.
The power law index is -1.12 +/- 0.04 and the cutoff energy,
parameterized as Epeak, is 176 +/- 10 keV.

The event fluence (10-1000 keV) in this time interval is
(1.45 +/- 0.04)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+3.7 s in the 10-1000 keV band is 15.4 +/- 0.3 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: GRB220521B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32128
SUBJECT: GRB 220521B: CALET Gamma-Ray Burst Monitor detection
DATE:    22/05/26 23:44:02 GMT
FROM:    Yuta Kawakubo at Louisiana State U./CALET  <kawakubo1@lsu.edu>

T. Sakamoto, A. Yoshida, 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 220521B (Konus-Wind detection: A.Ridnaia et al., GCN Circ 32106; 
IPN triangulation: Kozyrev et al., GCN Circ 32104) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 15:03:34.307 UTC on 21 May 2022
(http://cgbm.calet.jp/cgbm_trigger/flight/1337180454/index.html).
The burst signal was seen by only SGM detector.
No real-time CGBM GCN notice was distributed about this trigger because
the real-time communication from the ISS was off (loss of signal).

The burst light curve shows a single pulse which starts
at T-0.5 sec, peaks at T+0.8 sec, and ends at T+1.5 sec.
The T90 and T50 durations measured by the SGM data are 1.6 +/- 0.3 sec
and 0.8 +/- 0.2 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1337180454/

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


GRB_name: GRB220527A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32129
SUBJECT: GRB 220527A: AGILE detection
DATE:    22/05/27 12:18:27 GMT
FROM:    Alessandro Ursi at INAF/IAPS  <alessandro.ursi@gmail.com>

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

The AGILE satellite detected a burst at T0 = 2022-05-27 09:17:14.55 (UTC).
The event is clearly visible in the AGILE scientific ratemeters of the
SuperAGILE (SA; 20-60 keV), MiniCALorimeter (MCAL; 0.4-100 MeV), and
AntiCoincidence (AC; 50-200 keV) detectors. The event lasted about 15 s and
it released a total number of 1860 counts in the SA detector (above a
background rate of 50 Hz), 27875 counts in the MCAL detector (above a
background rate of 1380 Hz), and 67515 counts in the AC detector (above a
background rate of 3470 Hz). The AGILE ratemeter light curves can be found
at http://www.agilescienceapp.it/notices/GRB220527A_AGILE_RM.png .

The event also triggered a high time resolution MCAL data acquisition,
where it released 12500 counts in the detector, above a background rate of
630 Hz. We notice that most of the signal is revealed in the E < 1.4 MeV
energy channels. The MCAL light curve can be found at
http://www.agilescienceapp.it/notices/GRB220527A_078464_580727834.552109.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: GRB220527A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32130
SUBJECT: GRB 220527A: Fermi GBM Final Localization
DATE:    22/05/27 14:55:26 GMT
FROM:    Joe Mangan at UCD  <joseph.mangan@ucdconnect.ie>

The Fermi GBM team reports the detection of a likely Long GRB.

At 09:17:15.73 UT on 27 May 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220527A (trigger 675335840 / 220527387).

The on-ground calculated location, using the GBM trigger
data, is RA = 323.8, DEC = -10.6 (J2000 degrees,
equivalent to 21 h 35 m, -10 d 34 '), 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 43
degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220527387/quicklook/glg_skymap_all_bn220527387.png

The HEALPix FITS file, including the estimated localization systematic, can
be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220527387/quicklook/glg_healpix_all_bn220527387.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220527387/quicklook/glg_lc_medres34_bn220527387.gif


GRB_name: GRB220527A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32131
SUBJECT: GRB 220527A: Fermi-LAT detection
DATE:    22/05/27 16:25:14 GMT
FROM:    Magnus Axelsson at Stockholm U.  <magaxe@kth.se>

E. Bissaldi (Politecnico and INFN Bari), L. Scotton (CNRS/IN2P3/LUPM) and M. Axelsson (KTH & Stockholm Univ.) report on behalf of the Fermi-LAT team:


On May 27, 2022, Fermi-LAT detected high-energy emission from GRB 220527A, which was also detected by

Fermi-GBM (trigger 675335840 / 220527387, GCN 32130) and AGILE (Ursi et al. 2022. GCN 32129).


The best LAT on-ground location is found to be


RA, Dec = 323.57, -14.9  (degrees, J2000)


with an error radius of 0.08 deg (90 % containment, statistical error only). This was 49 deg from the LAT boresight at the time of the GBM trigger:


T0 = 09:17:15.73 UT.


The data from the Fermi-LAT show a significant increase in the event rate that is spatially and temporally correlated with the GBM emission with high significance. The photon flux above 100 MeV in the time interval 0-1000 s after the GBM trigger is (6.0 +/- 1.4)E-06 ph/cm2/s. The estimated photon index above 100 MeV is -2.0 +/- 0.2. The highest-energy photon is a 12 GeV event which is observed 89 seconds after the GBM trigger.

The Fermi-LAT point of contact for this burst is Elisabetta Bissaldi (elisabetta.bissaldi@ba.infn.it<http://ba.infn.it>).

The Fermi-LAT is a pair conversion telescope designed to cover the energy band from 20 MeV to greater than 300 GeV. It is the product of an international collaboration between NASA and DOE in the U.S. and many scientific institutions across France, Italy, Japan and Sweden.


GRB_name: GRB220527A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32132
SUBJECT: GRB 220527A: Swift ToO observations
DATE:    22/05/27 17:38:33 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 ToO observation of the Fermi/LAT GRB 220527A. 
Automated analysis of the XRT data will be presented online at
https://www.swift.ac.uk/ToO_GRBs/00021503

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. These are
not necessarily related to the Fermi/LAT event. 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: GRB220527A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32133
SUBJECT: GRB 220527A: Fermi GBM Observation
DATE:    22/05/27 18:13:27 GMT
FROM:    Joe Mangan at UCD  <joseph.mangan@ucdconnect.ie>

J. Mangan (UCD), R. Dunwoody (UCD), and C.Meegan (UAH)
report on behalf of the Fermi GBM Team:

At 09:17:15.73 UT on 27 May 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220527A (trigger 675335840 / 220527387),
which was also detected by the Fermi LAT (Bissaldi et al. 2022, GCN 32131)
and AGILE (Ursi et al 2022, GCN 32129). The Fermi GBM Final Real-time
Localization
(GCN 32130) is consistent with the Fermi LAT position.

The angle from the Fermi LAT boresight at the GBM trigger time is 49
degrees.

The GBM light curve consists of a double peak emission
with a duration (T90) of about 10.5 s (50-300 keV).
The time-averaged spectrum from T0-0.13 s to T0+21.38 s is best fit by
a Band function with Epeak = 151.6 +/- 2.7 keV,
alpha = -0.75 +/- 0.02, and beta = -2.55 +/- 0.05.

The event fluence (10-1000 keV) in this time interval is
(5.69 +/- 0.04)E-5 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+7.4 s in the 10-1000 keV band
is 92.6 +/- 0.7 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: GRB220527A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32135
SUBJECT: GRB 220527A: Swift-XRT afterglow detection
DATE:    22/05/28 01:10:03 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

B. Sbarufatti (PSU), A.P. Beardmore (U. Leicester), J.P. Osborne (U.
Leicester), P. D'Avanzo (INAF-OAB), M.G. Bernardini (INAF-OAB), E.
Ambrosi  (INAF-IASFPA) , D.N. Burrows (PSU), J. D. Gropp (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/LAT-detected burst GRB 220527A (Bissaldi et al. GCN Circ. 32131),
collecting 1.7 ks of Photon Counting (PC) mode data between T0+30.1 ks
and T0+31.9 ks. 

Two uncatalogued X-ray sources are detected, of which one ("Source 2")
is above the RASS 3-sigma upper limit at this position, and is
therefore likely the GRB afterglow. Using 1733 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 = 323.52805, -14.97183 which is equivalent to:

RA (J2000): 21h 34m 06.73s
Dec(J2000): 14d 58' 18.6"

with an uncertainty of 2.6 arcsec (radius, 90% confidence). This
position is 4.9 arcmin from the Fermi/LAT position.  The light curve is
consistent with a constant source of mean count rate 3.9e-01 ct/sec. A
power-law fit gives an index of 0.6 (+2.5, -1.1).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.83 (+0.21, -0.20). The
best-fitting absorption column is  9.8 (+6.1, -3.5) x 10^20 cm^-2,
consistent with the Galactic value of 6.2 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 (4.2 x
10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      9.8 (+6.1, -3.5) x 10^20 cm^-2
Galactic foreground: 6.2 x 10^20 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.83 (+0.21, -0.20)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00021503.
The results of the full analysis of the XRT observations are available
at https://www.swift.ac.uk/ToO_GRBs/00021503.

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


GRB_name: GRB220527A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32136
SUBJECT: GRB 220527A: Swift/UVOT detection
DATE:    22/05/28 02:22:50 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>

The Swift/UVOT began observations of the Fermi/LAT localization (GCN
32131) of GRB 220527A , collecting 1.7 ks of u band data between
T0+30.1 ks
and T0+31.9 ks after the Fermi GBM detection (32133).
A source consistent with the XRT afterglow position (GCN 32135) is
detected in the UVOT observation.

The preliminary UVOT position is:
RA,Dec (J2000): 323.52803, -14.97169

with an estimated u band magnitude of 17.8 +/- 0.07 in the UVOT
photometric system.


GRB_name: GRB220527A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32138
SUBJECT: GRB 220527A: MITSuME Akeno optical observation
DATE:    22/05/28 02:37:56 GMT
FROM:    Yuri Imai at Tokyo Inst of Tech  <imai@hp.phys.titech.ac.jp>

Y. Imai, S. Sato, R. Hosokawa, K. L. Murata, M. Sasada, M. Niwano, N.
Ito, Y. Takamatsu, M. Tateda, T. Hattori, Y. Yatsu, and N. Kawai
(Tokyo Tech) report on behalf of the MITSuME collaboration:

We observed the field of GRB 220527A (A. Ursi et al. GCN Circular
#32129, The Fermi GBM team et al. GCN Circular #32130, Bissaldi  et
al. GCN Circular #32131, Evans et al. GCN Circular #32132, Mangan et
al. GCN Circular #32133, Sbarufatti et al. GCN Circular #32135,
Tohuvavohu et al. GCN Circular #32136,) with the optical three color
(g', Rc, and Ic) CCD cameras attached to the MITSuME 50 cm telescope
Akeno.

The observation with a series of 60 sec exposures started at
2022-05-27 16:05:50 UT (6.8 hours after the AGILE detection). We
stacked the images with good conditions. Here we report magnitudes by
the forced-photometry at the Swift/XRT position (Sbarufatti et al. GCN
Circular #32135).

T0+[hour] |MID-UT | T-EXP[sec] | magnitudes of forced-photometry
------------------------------------------------------------------------------------------------
7.5 | 2022-05-27 16:46:53| 3780 | g'=18.9 +/- 0.2, Rc=18.5 +/- 0.1,
Ic=18.3 +/- 0.1
8.7 | 2022-05-27 17:58:38| 3420 | g'=18.9 +/- 0.2, Rc=18.6 +/- 0.1,
Ic=18.7 +/- 0.2
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time

We used PS1 catalog for flux calibration. The magnitudes are expressed
in the AB system. The images were processed in real-time through the
MITSuME GPU reduction pipeline (Niwano et al. 2021, PASJ, Vol.73,
Issue 1, Pages 4-24; https://github.com/MNiwano/Eclaire).


GRB_name: GRB220527A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32139
SUBJECT: GRB 220527A: CALET Gamma-Ray Burst Monitor detection
DATE:    22/05/28 03:10:53 GMT
FROM:    Yuta Kawakubo at Louisiana State U./CALET  <kawakubo1@lsu.edu>

K. Yamaoka (Nagoya U), A. Yoshida, T. Sakamoto, S. Sugita (AGU),
Y. Kawakubo (LSU), 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 bright long GRB 220527A (AGILE detection: Ursi et al., GCN Circ. 32129;
Fermi GBM Final Real-time Localization: Fermi GBM team, GCN Circ. 32130; 
Fermi-LAT detection: Bissaldi et al., GCN Circ. 32131) triggered the CALET
Gamma-ray Burst Monitor (CGBM) at 09:17:14.518 UTC on 27 May 2022
(http://cgbm.calet.jp/cgbm_trigger/flight/1337678064/index.html).
The burst signal was seen by all CGBM detectors.

The burst light curve shows a multi-peaked structure which starts
at T+0.5 sec, peaks at T+9.1 sec, and ends at T+21.9 sec.
The T90 and T50 durations measured by the SGM data are 10.2 +/- 1.0 sec
and 3.9 +/- 0.1 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1337678064/

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


GRB_name: GRB220527A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32140
SUBJECT: GRB 220527A: AstroSat CZTI detection
DATE:    22/05/28 05:23:18 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

R. Gopalakrishnan (IUCAA), V. Prasad (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 detection of a long GRB 220527A which was 
also reported by AGILE (Ursi et al. GCN 32129), Fermi-GBM (GCN 32130), 
Fermi-LAT (Bissaldi et al., GCN 32131), Swift-XRT (Sbarufatti et al., 
GCN 32135), Swift-UVOT (Tohuvavohu et al., GCN 32136) and CALET (Yamaoka 
et al., GCN 32139).

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 
2022-05-27 09:17:23.55 UTC. The measured peak count rate associated with 
the burst is 1879 (+251, -171) counts/s above the background in the 
combined data of four quadrants, with a total of 5318 (+224, -235) 
counts. The local mean background count rate was 496 (+4, -5) counts/s. 
Using cumulative rates, we measure a T90 of 7 (+1, -1) s.

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 2022-05-27 09:17:19.39 UTC. The 
measured peak count rate is 1880 (+96, -93) counts/s above the 
background in the combined Veto data of four quadrants, with a total of 
11483 (+534, -559) counts. The local mean background count rate was 1644 
(+6, -6) counts/s. We measure a T90 of 14 (+3, -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 [1]. 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: GRB220527A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32141
SUBJECT: GRB 220527A: NOT optical photometry and spectroscopic redshift
DATE:    22/05/28 06:34:21 GMT
FROM:    Dong Xu at NAOC/CAS  <dxu@nao.cas.cn>

D. Xu (NAOC), Z.P. Zhu (NAOC, HUST), L. Izzo (DARK/NBI), S.Y. Fu, X. Liu 
(NAOC), M. Aron (NOT), report on behalf of a larger collaboration:

We observed the field of GRB 220527A detected by AGILE (Ursi et al., GCN 
32129), Fermi (Fermi GBM team, GCN 32130; Bissaldi et al., GCN 32131), 
CALET (Yamaoka et la., GCN 32139), and AstroSat (Gopalakrishnan et al., 
GCN 32140), using the 2.56-m Nordic Optical Telescope (NOT) equipped 
with the ALFSOC camera. We carried out 3x120 s Sloan r-band photometry 
starting at 03:55:22 UT on 2022-05-28, i.e., 18.6 hr since the Fermi/GBM 
trigger, followed by 2x1800 s spectroscopy covering wavelength of ~ 3600 
- 9000 AA.

The previously reported optical afterglow (Tohuvavohu et al., GCN 32136; 
Imai et al., GCN 32138) is clearly detected in each single r-band image, 
and has decayed to r = 19.55 +/- 0.02 mag, calibrated with the 
PAN-STARRS field.

A blue continuum is throughout the spectrum, superimposed with a few 
relatively prominent absorption features, among which we identify as Ni 
II, Fe II, Mn II, Mg II, all at a common redshift of z =0.857, using old 
calibrations. A weak emission feature might also be detected, 
interpreted as due to [O II] at the same redshift. We thus conclude z 
=0.857 is the redshift of the burst.


GRB_name: GRB220527A
Detection_method: Fermi LAT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32143
SUBJECT: GRB 220527A: MeerLICHT afterglow observations
DATE:    22/05/28 08:11:28 GMT
FROM:    Simon de Wet at UCT  <dwtsim002@myuct.ac.za>

S. de Wet (UCT), P.J. Groot (Radboud/UCT/SAAO) and P.M. Vreeswijk (Radboud)
report on behalf of the MeerLICHT consortium:

Following the detection of GRB 220527A by AGILE (Ursi et al., GCN 32129),
Fermi/GBM (Fermi GBM Team, GCN 32130) and Fermi/LAT (Bissaldi et al., GCN
32131), the 0.6m wide-field MeerLICHT telescope, located at Sutherland,
South Africa, obtained 2x600 s exposures in the q-band and a single 300 s
exposure in each of the g and r bands covering the entire Fermi/LAT error
region beginning 17.68 hours after the GRB trigger.

We detect the previously reported afterglow to GRB 220527A (Sbarufatti et
al., GCN 32135; Tohuvavohu, GCN 32136; Imai et al., GCN 32138; Xu et al.,
GCN 32141) at the UVOT position with AB magnitudes:

g = 19.72 +/- 0.04
r = 19.55 +/- 0.06
q = 19.57 +/- 0.02

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: GRB220527A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32144
SUBJECT: GRB 
DATE:    22/05/28 10:32:22 GMT
FROM:    Andrea Saccardi at Observatoire de Paris  <andrea.saccardi@obspm.fr>

A. Saccardi (GEPI, Observatoire de Paris), L. Izzo (DARK/NBI), and D. Xu (NAOC)
report on behalf of the Stargate collaboration:

We observed the afterglow counterpart of GRB 220527A detected by Swift-XRT (B. Sbarufatti et al. GCN Circ. 32135) during the follow-up observations of the Fermi/LAT-detected burst GRB 220527A (E. Bissaldi et al. GCN Circ. 32131) using  the ESO VLT UT3 (Melipal) equipped with the X-shooter spectrograph. 

A spectrum was acquired covering the wavelength range 3000-21000 AA, and consisting of 4 exposures of 600 s each. The observation started at 06:19:10 UT on 2022-05-28 (0.88 days after the GRB detection by Fermi/GBM).

From the detection of several absorption lines, which we identified as due to Al III, Ni II, Fe II, Mn II, Mg II, Mg I, and Ca II we infer a redshift z=0.857, which is in agreement with the redshift reported by the NOT (D. Xu et al. GCN Circ. 32141). We note also the presence of a possible intervening absorber, through the identification of Mg II, at z=0.455 which coincides with the photometric redshift of a nearby source visible in the Pan-STARRS archival images.

We acknowledge excellent support from the ESO observing staff in Paranal, in particular Rob van Holstein (ESO fellow) and Felipe Gaete (Telescope operator).


GRB_name: GRB220527A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32145
SUBJECT: GRB 220527A: REM optical/NIR observations
DATE:    22/05/28 15:04:15 GMT
FROM:    Paolo D'Avanzo at INAF-OAB  <pda.davanzo@gmail.com>

P. D'Avanzo, D. Fugazza, A. Melandri, S. Covino (INAF-OAB) on behalf of the REM team, report:

We observed the field of GRB 220527A (Ursi et al., GCN Circ. 32129; Fermi GBM Team, GCN Circ. 32130; Bissaldi et al., GCN Circ. 32131) with the REM 60cm robotic telescope  located at the ESO premise of La Silla (Chile). The observations were carried in the g, r, i, z, J and K bands, starting on 2022 May 28 at 07:27:54 UT (i.e. about 22.2 hours after the burst). 

From preliminary photometry we derive the following magnitudes and upper limits (3sigma c.l.) for the optical afterglow (Tohuvavohu et al., GCN Circ. 32136; Imai et al., GCN Circ. 32138; Xu et al., GCN 32141; de Wet et al., GCN Circ. 32143):


g = 20.4 +/- 0.3 (*)
r = 19.4 +/- 0.2
i = 19.4 +/- 0.2
z > 18.4
(* marginal detection; AB calibrated against the Pan-STARRS catalogue)

J > 17.7
K > 14.9
(Vega; calibrated against the 2MASS catalogue) 


at a mid time of t-t0 ~ 22.4 hours.


GRB_name: GRB220527A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32146
SUBJECT: GRB 220527A: AST3-3 Yaoan Optical Observation
DATE:    22/05/28 15:20:11 GMT
FROM:    Tianrui Sun at Purple Mountain Obs,CAS  <trsun@pmo.ac.cn>

Tianrui Sun (Purple Mountain Observatory), Lei Hu, Maokai Hu, Xuefeng Wu, Lei Liu, Kelai Meng, Xiaoyan Li (Nanjing Institute of Astronomical Observation Technology),
Zhengyang Li, Xiangyan Yuan, Lifan Wang (TAMU), Xiaofeng Wang (Tsinghua University), report on behalf the AST3 Team:
    
Following the detection of GRB 220527A detected by AGILE (Ursi et al., GCN 
32129), Fermi (Fermi GBM team, GCN 32130; Bissaldi et al., GCN 32131), CALET (Yamaoka et la., GCN 32139), and AstroSat (Gopalakrishnan et al., 
GCN 32140), we use Antarctic Survey Telescope 3-3 at Yaoan Astronomy Observation (China, Yunnan) to follow up for the afterglow (Sbarufatti et
al., GCN 32135; Tohuvavohu, GCN 32136; Imai et al., GCN 32138; Xu et al.,
GCN 32141; Simon et al. 32143; D'Avanzo et al., 32145).




We observed the target position with 14 x 60s exposure in g-band starting from 27 May 2022, UTC 21:11:36.003, 

about 11.9 hours after the burst.

The magnitude detection at the Swift UVOT position (GCN 32136) on the combined images for the GRB afterglow :
g=19.3 +/- 0.06


We used the PS1 catalogue as the magnitude reference for calibration. 


GRB_name: GRB220528A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32147
SUBJECT: GRB 220528A: Fermi GBM Final Localization
DATE:    22/05/28 15:21:54 GMT
FROM:    Joe Mangan at UCD  <joseph.mangan@ucdconnect.ie>

The Fermi GBM team reports the detection of a likely short GRB.

At 06:12:47.41 UT on 28 May 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220528A (trigger 675411172 / 220528259).

The on-ground calculated location, using the GBM trigger
data, is RA = 311.2, DEC = 24.3 (J2000 degrees,
equivalent to 20 h 44 m, 24 d 18 '), with a statistical uncertainty
of 4.9 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 68
degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220528259/quicklook/glg_skymap_all_bn220528259.png

The HEALPix FITS file, including the estimated localization systematic, can
be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220528259/quicklook/glg_healpix_all_bn220528259.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220528259/quicklook/glg_lc_medres34_bn220528259.gif


GRB_name: GRB220528B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32148
SUBJECT: GRB 220528B: Swift/BAT-GUANO detection outside the coded FOV
DATE:    22/05/28 17:32:30 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>

Gayathri Raman (PSU), Aaron Tohuvavohu (U Toronto),  James DeLaunay
(UAlabama), Jamie A. Kennea (PSU), report:

Swift/BAT did not localize GRB 220528B onboard (T0:
2022-05-28T06:12:47 UTC, Fermi/GBM GCN 32147).

The Fermi notice, 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,
arXiv:2111.01769), detects the burst with a sqrt(TS) of 12.2 in a
0.512 s analysis time bin.
The burst episode as seen by BAT is ~1 s long.

NITRATES results are consistent with a burst coming from outside of
the coded FoV, as indicated by the Fermi/GBM localization (GCN 32147).

See Section 9.1 and Figure 20 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: GRB220528A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32149
SUBJECT: Correction to GCN 32148: Should be GRB 220528A
DATE:    22/05/28 17:39:03 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>

The burst detection reported in GCN 32148 "GRB 220528B:
Swift/BAT-GUANO detection... " was misnamed.
The burst is GRB 220528A (see Fermi/GBM discovery and naming in GCN 32147).
I apologize for the mistake.


GRB_name: GRB220530A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32150
SUBJECT: GRB 220530A: Fermi GBM Final Real-time Localization
DATE:    22/05/30 11:20:18 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 11:09:58 UT on 30 May 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220530A (trigger 675601803.514142 / 220530465).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 159.4, Dec = 13.6 (J2000 degrees, equivalent to J2000 10h 37m, 13d 35'), with a statistical uncertainty of 8.5 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/2022/bn220530465/quicklook/glg_skymap_all_bn220530465.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220530465/quicklook/glg_healpix_all_bn220530465.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220530465/quicklook/glg_lc_medres34_bn220530465.gif


GRB_name: GRB220527A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32152
SUBJECT: Konus-Wind observation of GRB 220527A
DATE:    22/05/30 16:59:09 GMT
FROM:    Alexandra Lysenko at Ioffe Institute  <alexandra.lysenko@mail.ioffe.ru>

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

The long-duration GRB 220527A
(AGILE detection: Ursi et al., GCN Circ. 32129;
Fermi-LAT detection: Bissaldi et al., GCN Circ. 32131;
Fermi-GBM detection: The Fermi GBM team, GCN Circ. 32130;
Mangan et al., GCN Circ. 32133;
CALET detection: Yamaoka et al., GCN Circ. 32139;
AstroSat CZTI detection: Gopalakrishnan et al., GCN Circ. 32140)
triggered Konus-Wind at T0=33441.517 s UT (09:17:21.517).

The burst light curve shows a multipeaked structure
which starts at ~T0-4.1 s and has a total duration of ~21.3 s.
The emission is seen up to ~16 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB220527_T33441/

As observed by Konus-Wind, the burst
had a fluence of 5.98(-0.31,+0.32)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+5.152s,
of 1.73(-0.21,+0.22)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+13.568 s)
is best fit in the 20 keV - 16 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.80(-0.12,+0.13),
the high energy photon index beta = -2.55(-0.13,+0.10),
the peak energy Ep = 154(-10,+10) keV
(chi2 = 115/98 dof).

The spectrum near the maximum count rate
(measured from T0+3.584 to T0+5.376 s)
is best fit in the 20 keV - 16 MeV range
by the GRB (Band) model with the following parameters:
the low-energy photon index alpha = -0.49(-0.18,+0.21),
the high energy photon index beta = -3.24(-0.53,+0.31),
the peak energy Ep = 146(-9,+9) keV
(chi2 = 72/64 dof).

For both spectra, we note a prominent count excess over the model
at energies above ~5 MeV. The excess can be modeled by
an additional power-law component with a photon index of <~2.

Assuming the redshift z=0.857 (Xu et al., GCN Circ. 32141)
and a standard cosmology model with H_0 = 67.7 km/s/Mpc,
Omega_M = 0.310, and Omega_Lambda = 0.689 (Planck Collab 2018, Paper VI),
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is 1.22(-0.06,+0.07)x10^53 erg,
the peak luminosity L_iso is 6.53(-0.81,+0.84)x10^52 erg/s,
and the rest-frame peak energy of the time-integrated spectrum,
Ep,i,z is 286(-18,+19) keV

With the obtained estimates, GRB 220527A lies inside 68% prediction bands
for both 'Amati' and 'Yonetoku' relations for the sample of >300 long KW 
GRBs
with known redshifts (Tsvetkova et al., 2017; Tsvetkova et al., 2021),
see http://www.ioffe.ru/LEA/GRBs/GRB220527_T33441/GRB220527A_rest_frame.pdf

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


GRB_name: GRB220530A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32153
SUBJECT: Fermi GRB 220530A: Global MASTER-Net observations report 
DATE:    22/05/30 17:00:34 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 220530A ( Fermi GBM team, GCN 32150) errorbox  19032 sec after notice time and 19042 sec after trigger time at 2022-05-30 16:27:21 UT, with upper limit up to  18.7 mag. Observations started at twilight.  The observations began at zenith distance = 45 deg. The sun  altitude  is -9.6 deg. 

The galactic latitude b = 56 deg., longitude l = 231 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1990415

We obtain a following upper limits.  

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

   19073 | 2022-05-30 16:27:21 |         MASTER-SAAO | (10h 33m 16.57s , +12d 38m 44.9s) |   C |    60 | 16.4 |        
   19152 | 2022-05-30 16:28:40 |         MASTER-SAAO | (10h 41m 18.61s , +12d 37m 46.0s) |   C |    60 | 16.7 |        
   19243 | 2022-05-30 16:30:11 |         MASTER-SAAO | (10h 38m 18.02s , +14d 33m 41.8s) |   C |    60 | 17.0 |        
   19323 | 2022-05-30 16:31:31 |         MASTER-SAAO | (10h 46m 30.38s , +14d 31m 55.2s) |   C |    60 | 17.1 |        
   19413 | 2022-05-30 16:33:01 |         MASTER-SAAO | (10h 22m 42.94s , +14d 33m 06.7s) |   C |    60 | 16.6 |        
   19493 | 2022-05-30 16:34:21 |         MASTER-SAAO | (10h 30m 54.84s , +14d 34m 05.5s) |   C |    60 | 17.2 |        
   19585 | 2022-05-30 16:35:53 |         MASTER-SAAO | (10h 28m 59.84s , +10d 44m 05.0s) |   C |    60 | 17.1 |        
   19676 | 2022-05-30 16:37:24 |         MASTER-SAAO | (10h 37m 11.28s , +10d 44m 16.3s) |   C |    60 | 17.3 |        
   19756 | 2022-05-30 16:38:44 |         MASTER-SAAO | (10h 28m 29.73s , +16d 26m 25.4s) |   C |    60 | 17.3 |        
   19846 | 2022-05-30 16:40:14 |         MASTER-SAAO | (10h 36m 50.40s , +16d 28m 04.8s) |   C |    60 | 17.8 |        
   19926 | 2022-05-30 16:41:34 |         MASTER-SAAO | (10h 17m 52.90s , +12d 40m 21.7s) |   C |    60 | 17.6 |        
   20017 | 2022-05-30 16:43:05 |         MASTER-SAAO | (10h 26m 07.04s , +12d 39m 18.9s) |   C |    60 | 17.8 |        
   20096 | 2022-05-30 16:44:24 |         MASTER-SAAO | (10h 33m 20.86s , +12d 38m 17.1s) |   C |    60 | 18.1 |        
   20188 | 2022-05-30 16:45:56 |         MASTER-SAAO | (10h 41m 35.71s , +12d 38m 18.2s) |   C |    60 | 18.5 |        
   20279 | 2022-05-30 16:47:27 |         MASTER-SAAO | (10h 38m 27.28s , +14d 34m 00.9s) |   C |    60 | 18.6 |        
   20359 | 2022-05-30 16:48:47 |         MASTER-SAAO | (10h 46m 39.92s , +14d 32m 42.8s) |   C |    60 | 18.6 |        
   20450 | 2022-05-30 16:50:18 |         MASTER-SAAO | (10h 22m 57.25s , +14d 34m 10.0s) |   C |    60 | 18.4 |        
   20529 | 2022-05-30 16:51:37 |         MASTER-SAAO | (10h 31m 03.96s , +14d 33m 31.5s) |   C |    60 | 18.7 |        
   20620 | 2022-05-30 16:53:08 |         MASTER-SAAO | (10h 29m 07.46s , +10d 46m 30.5s) |   C |    60 | 18.7 |        
Filter C is a clear (unfiltred) band. 


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


GRB_name: GRB220528A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32155
SUBJECT: GRB 220528A: Fermi GBM Observation
DATE:    22/05/31 15:31:23 GMT
FROM:    Joe Mangan at UCD  <joseph.mangan@ucdconnect.ie>

J.Mangan (UCD), S. Lesage (UAH) and C.Meegan (UAH) report on behalf of the
Fermi GBM Team:

"At 06:12:47.41 UT on 28 May 2022, the Fermi Gamma-Ray Burst Monitor (GBM)
triggered and located GRB 220528A (trigger 675411172 / 220528259), which
was also
detected by the Swift/BAT-GUANO (Raman et al. 2022, GCN 32148 and GCN
32149).

The Fermi GBM Final Real-time Localization has been reported in GCN 32147.

The GBM light curve consists of a single peak with a duration (T90) of
about 0.58 s (50-300 keV).
The time-averaged spectrum from T0-0.128 s to T0+0.576 s is best fit by a
power law function with an exponential
high-energy cutoff. The power law index is 0.08 +/- 0.17 and the cutoff
energy, parameterized as Epeak, is 467.5 +/- 50.8 keV
The event fluence (10-1000 keV) in this time interval is (1.59 +/-
0.11)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-0.064 s in the 10-1000 keV band is 4.2 +/- 0.2 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: GRB220528A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32156
SUBJECT: IPN triangulation of GRB 220528A (short)
DATE:    22/06/01 09:13:49 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

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

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

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

and

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

The short-duration GRB 220528A
(Fermi-GBM detection: Fermi GBM Team, GCN Circ. 32147;
Mangan et al., GCN Circ. 32155;
Swift/BAT-GUANO detection: Raman et al., GCN Circ. 32148)
was detected by Fermi (GBM trigger 675411172),
INTEGRAL (SPI-ACS), Konus-Wind, and Swift (BAT)
at about 22367 s UT (06:12:47).
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:
   312.961 (20h 51m 51s) +18.856 (+18d 51' 22")
  Corners:
   315.010 (21h 00m 02s) +16.077 (+16d 04' 38")
   315.232 (21h 00m 56s) +16.369 (+16d 22' 08")
   310.761 (20h 43m 03s) +21.508 (+21d 30' 30")
   310.547 (20h 42m 11s) +21.215 (+21d 12' 55")
  ---------------------------------------------
The error box area is 2.3 sq. deg, and its maximum
dimension is 6.8 deg (the minimum one is 21 arcmin).
The Sun distance was 102 deg.

This box may be improved.

The IPN localization is consistent with, but reduces the area of, the
Fermi-GBM final localization (GCN Circ. 32147).

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220528_T22370/IPN

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


GRB_name: GRB220528A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32157
SUBJECT: Konus-Wind detection of GRB 220528A
DATE:    22/06/01 09:20:20 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

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

The short-duration GRB 220528A
(Fermi-GBM detection: Fermi GBM Team, GCN Circ. 32147;
Mangan et al., GCN Circ. 32155;
Swift/BAT-GUANO detection: Raman et al., GCN Circ. 32148;
IPN triangulation: Svinkin at al., GCN Circ. 32156)
triggered Konus-Wind at T0=22370.380 s UT (06:12:50.380).

The burst light curve shows a multipeaked structure,
which starts at T0-0.1 s and has a total duration of ~0.7 s.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB220528_T22370/

As observed by Konus-Wind, the burst
had a fluence of 1.85(-0.03,+0.54)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0+0.034 s,
of 7.88(-1.57,+2.77)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

Since the main fraction of the burst emission was detected
before the trigger, the spectral analysis was performed using
the KW 3-channel light curve data.

Modelling the KW 3-channel time-integrated spectrum
(measured from T0-0.402 s to T0+0.296 s)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep),
yields alpha = -0.06(-0.32,+0.38) and Ep = 542(-78,+118) keV.

All the quoted errors are at the 68% confidence level.
All the quoted values are preliminary.


GRB_name: GRB220527A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32158
SUBJECT: GRB 220527A: Lick 3m Optical Observations
DATE:    22/06/02 23:05:53 GMT
FROM:    Weikang Zheng at UC Berkeley  <weikang@berkeley.edu>

WeiKang Zheng, Thomas G. Brink and Alexei V. Filippenko (UC Berkeley)
report on behalf of the KAIT GRB team:

We observed the field of GRB 220527A (AGILE detection: Ursi et al., GCN
32129; Fermi detection: Fermi GBM team, GCN 32130, Bissaldi et al., GCN
32131, Mangan et al., 32133; CALET detection: Yamaoka et al., GCN 32139;
AstroSat detection: Gopalakrishnan et al., GCN 32140; Konus-Wind detection:
Lysenko et al. GCN 32152)
with the 3m Shane telescope (located at Lick Observatory) on May 28
and 30 UT. Observations were performed in unfiltered images with the
Kast Dual Spectrograph simultaneously in both blue and red side with
the d57 dichroic. We detected the optical afterglow (Tohuvavohu et al.,
GCN 32136; Imai et al., GCN 32138; Xu et al., GCN 32141; de Wet et al.,
GCN 32143; D'Avanzo et al., GCN 32145; Sun et al., GCN 32146)
in our coadd images. We calibrated our blue side images to g band and
red side images to I band from the Pan-STARRS1 catalog. We measure its
brightness to be the following:

1.09d g = 20.3 +/- 0.2
1.09d I = 19.4 +/- 0.2
3.08d I = 21.2 +/- 0.3


GRB_name: GRB220527A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32159
SUBJECT: GRB 220527A: MITSuME Akeno continued optical observation
DATE:    22/06/03 10:00:43 GMT
FROM:    Masafumi Niwano at Tokyo Institute of Tech  <niwano@hp.phys.titech.ac.jp>

M. Niwano, S. Sato, M. Tateda, N. Higuchi, T. Hattori, R. Hosokawa, K. 
L. Murata, M. Sasada, N. Ito, Y. Takamatsu, Y. Imai, Y. Yatsu, and N. 
Kawai (Tokyo Tech) report on behalf of the MITSuME collaboration:

We observed the field of GRB 220527A (A. Ursi et al. GCN Circular 
#32129, The Fermi GBM team GCN Circular #32130, E. Bissaldi et al. GCN 
Circular #32131, P. A. Evans et al. GCN Circular #32132, J. Mangan et 
al. GCN Circular #32133, B. Sbarufatti et al. GCN Circular #32135, 
Tohuvavohu et al. GCN Circular #32136, Y. Imai et al. GCN Circular 
#32138, K. Yamaoka et al. GCN Circular #32139, R. Gopalakrishnan et al. 
GCN Circular #32140, D. Xu et al. GCN Circular #32141, S. de Wet et al. 
GCN Circular #32143, P. D'Avanzo et al. GCN Circular #32145, T. Sun et 
al. GCN Circular #32146, A. Lysenko et al. GCN Circular #32152, W. Zheng 
et al. GCN Circular #32158) with the optical three color (g', Rc, and 
Ic) CCD cameras attached to the MITSuME 50 cm telescope Akeno.

The observation with a series of 60 sec exposures started at 2022-05-28 
16:06:39 UT (1.3 days after the AGILE detection). We stacked the images 
with good conditions. The point source was presumably detected at the 
Swift/XRT position (Sbarufatti et al. GCN Circular #32135) with S/N~3 
only in the Rc-band image. Here we report the Rc-band magnitude by the 
forced-photometry at the position and 5-sigma limits.

T0+[days] | MID-UT | T-EXP[sec] | magnitudes of forced-photometry | 
5-sigma limits
------------------------------------------------------------------------------------------------
1.3 | 2022-05-28 17:39:36 | 4980 | Rc=20.5+/-0.3 | g'<18.6, Rc<19.3, Ic<18.5
------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time

We used PS1 catalog for flux calibration. The magnitudes are expressed 
in the AB system. The images were processed in real-time through the 
MITSuME GPU reduction pipeline (Niwano et al. 2021, PASJ, Vol.73, Issue 
1, Pages 4-24; https://github.com/MNiwano/Eclaire).


GRB_name: GRB220603A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32161
SUBJECT: GRB 220603A: Swift/BAT-GUANO detection outside the coded FOV
DATE:    22/06/04 03:19:12 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>

James DeLaunay (UAlabama), Aaron Tohuvavohu (U Toronto), Gayathri
Raman (PSU), Jamie A. Kennea (PSU), report:

Swift/BAT did not localize GRB 220603A onboard (T0:
2022-06-03T01:41:23.4 UTC, GECAM trig. utn220603_014123_GECAMb).

The GECAM notice, 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,
arXiv:2111.01769), detects the burst with a sqrt(TS) of 26.5 in a
8.192 s analysis time bin.
The burst episode as seen by BAT is ~10 s long.

NITRATES results indicate a burst coming from outside of the coded
FoV, with DeltaLLHOut of -7.

See Section 9.1 and Figure 20 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: GRB220601A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32163
SUBJECT: IPN triangulation of GRB 220601A (long)
DATE:    22/06/04 13:39:20 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,

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

S. Xiao, S.-L. Xiong, X.-Q. Li, X.-Y. Wen, L.-M. Song, S.-J. Zheng,
W.-X. Peng, and F. Zhang on behalf of the GECAM 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 220601A
was detected by Konus-Wind, INTEGRAL (SPI-ACS), GECAM-B,
and Mars-Odyssey (HEND) at about 22766 s UT (06:19:26).

We have triangulated it to a preliminary, 3 sigma error box
whose coordinates are:
  ---------------------------------------------
   RA(2000), deg                 Dec(2000), deg
  ---------------------------------------------
  Center:
   224.703 (14h 58m 49s) -47.978 (-47d 58' 41")
  Corners:
   221.059 (14h 44m 14s) -50.313 (-50d 18' 48")
   221.153 (14h 44m 37s) -50.501 (-50d 30' 02")
   227.990 (15h 11m 58s) -45.375 (-45d 22' 31")
   227.888 (15h 11m 33s) -45.177 (-45d 10' 37")
  ---------------------------------------------
The error box area is 1.2 sq. deg, and its maximum
dimension is 7.0 deg (the minimum one is 11 arcmin).
The Sun distance was 144 deg.

This box may be improved.

A triangulation map and HEALPix FITS file are posted at
http://www.ioffe.ru/LEA/GRBs/GRB220601_T22766/IPN/

The time history and spectrum will be given in forthcoming GCN Circulars.


GRB_name: GRB220606A
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32164
SUBJECT: GRB 220606A: Fermi GBM Final Real-time Localization
DATE:    22/06/06 00:46:11 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 00:35:39 UT on 6 Jun 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220606A (trigger 676168544.281518 / 220606025).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 258.2, Dec = -26.0 (J2000 degrees, equivalent to J2000 17h 12m, -26d 00'), with a statistical uncertainty of 15.6 degrees.

The angle from the Fermi LAT boresight is 94.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220606025/quicklook/glg_skymap_all_bn220606025.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220606025/quicklook/glg_healpix_all_bn220606025.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220606025/quicklook/glg_lc_medres34_bn220606025.gif


GRB_name: GRB220606B
Detection_method: Fermi GBM final loc
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32165
SUBJECT: GRB 220606B: Fermi GBM Final Real-time Localization
DATE:    22/06/06 01:13:56 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 01:03:28 UT on 6 Jun 2022, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 220606B (trigger 676170213.675398 / 220606044).

The on-ground calculated location, using the Fermi GBM trigger data, is RA = 22.4, Dec = -50.0 (J2000 degrees, equivalent to J2000 01h 29m, -50d 00'), with a statistical uncertainty of 12.1 degrees.

The angle from the Fermi LAT boresight is 20.0 degrees.

The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220606044/quicklook/glg_skymap_all_bn220606044.png

The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220606044/quicklook/glg_healpix_all_bn220606044.fit

The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2022/bn220606044/quicklook/glg_lc_medres34_bn220606044.gif


GRB_name: GRB220606B
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32166
SUBJECT: Fermi GRB 220606B: Global MASTER-Net observations report 
DATE:    22/06/06 01:30:25 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-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 220606B ( Fermi GBM team, GCN 32165) errorbox  720 sec after notice time and 754 sec after trigger time at 2022-06-06 01:16:03 UT, with upper limit up to  19.3 mag. The observations began at zenith distance = 65 deg. The sun  altitude  is -53.7 deg. 

The galactic latitude b = -66 deg., longitude l = 287 deg.


Real time updated cover map and OT discovered available here: 
https://master.sai.msu.ru/site/master2/observ.php?id=1997640

We obtain a following upper limits.  

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

     785 | 2022-06-06 01:16:03 |         MASTER-SAAO | (01h 27m 52.53s , -50d 19m 46.2s) |   C |    60 | 19.0 |        
     875 | 2022-06-06 01:17:34 |         MASTER-SAAO | (01h 40m 26.17s , -50d 17m 58.4s) |   C |    60 | 19.2 |        
     957 | 2022-06-06 01:18:55 |         MASTER-SAAO | (01h 24m 27.36s , -48d 24m 22.5s) |   C |    60 | 19.3 |        
    1265 | 2022-06-06 01:24:03 |         MASTER-SAAO | (01h 36m 29.45s , -48d 26m 09.1s) |   C |    60 | 19.3 |        
Filter C is a clear (unfiltred) band. 


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


GRB_name: GRB220606B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  32167
SUBJECT: GRB 220606B: Swift/BAT-GUANO candidate arcminute localization of a short burst
DATE:    22/06/06 12:23:36 GMT
FROM:    Aaron Tohuvavohu at U Toronto  <aaron.tohu@gmail.com>

Aaron Tohuvavohu (U Toronto), James DeLaunay (UAlabama), Gayathri
Raman (PSU), Jamie A. Kennea (PSU), report:

Swift/BAT did not localize GRB 220606B onboard (T0:
2022-06-06T01:03:28 UTC, Fermi/GBM GCN 32165).

The Fermi notice, 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,
arXiv:2111.01769), detects the burst in a 0.512 s analysis time bin
with a sqrt(TS) of 10.7.
The duration of the burst as seen by BAT is less than 0.5 s.

A candidate arcminute localization is found with DeltaLLHOut of 11.3
and a DeltaLLHPeak of 3.1.
For this reason we can confidently claim detection, and preference for
an in FOV origin, but the best fit arcmin localization is not strongly
preferred over other positions.

See Section 9.1 and Figure 20 in the NITRATES paper for brief
descriptions and interpretations of sqrt(TS), DeltaLLHPeak, and
DeltaLLHOut.

The BAT position is
RA, Dec = 28.474, -54.471 deg which is
   RA(J2000)  = 01h 53m 53.76s
   Dec(J2000) = -54d 28â€² 15.6â€³
with an estimated uncertainty of 5 arcmin.

This position is consistent with the Fermi/GBM localization (GCN 32165).

XRT and UVOT follow-up has been requested.
Results of follow-up observations will be reported in future circulars.

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/


