# GCN_circulars

GRB_name: GRB180624A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22838
SUBJECT: GRB 180624A: MITSuME Okayama optical upper limits
DATE:    18/06/25 04:46:32 GMT
FROM:    Ryosuke Itoh at Tokyo Institute of Tech.  <itoh@hp.phys.titech.ac.jp>

R. Itoh,  K. L. Murata, Y. Tachibana, K. Morita,
K. Shiraishi, M. Oeda, R. Adachi, K. Iida, S. Niwano,   Y. Yatsu, and
N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We observed the field of GRB 180624A (S. L. Gibson et al., GCN Circular #22832)
with the optical three color (g', Rc and Ic) CCD camera attached
to the MITSuME 50cm telescope of Okayama Astrophysical Observatory.

The observation started on 2018-06-24 13:51:38.54 UT (~118 sec after
the burst). We did not find any new point source within the
enhanced XRT error circle in all the three bands.

We obtained following limits for the magnitudes.

T0+[sec]    MID-UT      T-EXP[sec]    g'       Rc        Ic
-------------------------------------------------------------------------------------------------------
~118      ~13:52:08      60   >15.5   >16.1   >16.2
~1537    ~14:15:47   2100   >17.2   >17.7   >17.6
-------------------------------------------------------------------------------------------------------

T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used UCAC-4 catalog for flux calibration.


GRB_name: GRB180624A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22839
SUBJECT: GRB 180624A: LCO Siding Springs afterglow candidate
DATE:    18/06/25 06:43:03 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi, R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell 
(U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU), A. Cucchiara 
(U. of Virgin Islands) on behalf of a large collaboration report:

One LCO 1-m unit at Siding Springs Observatory began observing Swift GRB 
180624A (Gibson et al. GCN 22832) on June 24, 14:18 UT (28.5 min since 
the GRB trigger time) with the SDSS r filter. Within the enhanced 
Swift-XRT error circle (Goad et al. GCN 22835) we find an uncatalogued 
object with a magnitude of r'=19.92 +- 0.10 (AB) at a mid time of 0.54 
hours since the GRB trigger time at the following position:

RA(J2000) = 21:12:23.38
DEC(J2000)= -02:20:16.7

with an error radius of ~1".


GRB_name: GRB180624A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22840
SUBJECT: GRB 180624A: GROND observations
DATE:    18/06/25 08:09:51 GMT
FROM:    Patricia Schady at MPE/Swift  <pschady@mpe.mpg.de>

Patricia Schady (MPE Garching) reports:

We observed the field of GRB 180624A (Swift trigger 844192; Gibson et al.,
GCN #22832) simultaneously in g'r'i'z'JHK with GROND (Greiner et al. 2008,
PASP 120, 405) mounted at the 2.2 m MPG telescope at ESO La Silla
Observatory (Chile).

Observations started at 04:42 UT on 2018-06-25, 14.9 hrs after the GRB
trigger. They were performed under poor seeing conditions and at an
average airmass of 1.5.

A source is visible within the 1.5" enhanced Swift-XRT error circle
reported by GOAD et al. (GCN #22835), and consistent with the position of
the optical afterglow candidate reported by Guidorzi et al. (GCN #22839).
The source appears extended and most of the flux in the JHK bands is to
the NW of the  afterglow error circle.

Based on a total of 22 min exposure time in g'r'i'z', we estimate
preliminary AB magnitudes of

g' = 21.5 +/- 0.1 mag
r' = 20.2 +/- 0.1 mag
i' = 19.9 +/- 0.1 mag
z' = 19.6 +/- 0.1 mag

A fit to the GROND optical SED implies a photometric redshift of
z_phot=3.75+/-0.10.

Given magnitudes are calibrated against SDSS field stars and are not
corrected for the expected Galactic foreground extinction corresponding to
a reddening of E_(B-V)=0.04 in the direction of the burst (Schlafly &
Finkbeiner 2011).

We thank Markus Rabus for the excellent support from La Silla.


GRB_name: GRB180613A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22841
SUBJECT: GRB 180613A: LCO Afterglow detection
DATE:    18/06/25 11:26:35 GMT
FROM:    Antonino Cucchiara at UVI  <antonino.cucchiara@uvi.edu>

A. Cucchiara, D. Morris (U. Virgin Islands), C. Guidorzi,
R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell
(U. Bath), report report on behalf of a larger collaboration:


"On June 13.84 UT  (T_0 +4.5 hours) we began observing the
center of the field of GRB 180613A (Tohuvavohu et al. GCN 22769,
Beardmore et al. GCN 22773) using the Las Cumbres Observatory
1m telescope located South Africa Astronomical Observatory.

We performed a series of 5x120s observations in SDSS-i' and
SDSS-r' band for a total of 20 minutes on sky.

In the full median stacked i'-band images we clearly identified the
NIR counterpart reported by Thoene et al. (GCN #2275, #22820).
This object is also marginally detected in our r' band stack.

We estimate the following brightness for the optical counterpart:

i' = 19.3 +- 0.6

We caution the usage of this measurement due to the high sky
background near the GRB location caused by the presence of the
nearby by a nearby 5.6 mag star (Schady et al. GCN #22777).

This magnitude is calibrated against nearby UCAC4 sources,
and is not corrected for Galactic extinction."


GRB_name: GRB180618A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22842
SUBJECT: GRB 180618A: AstroSat CZTI detection
DATE:    18/06/25 13:49:11 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:

Analysis of Astrosat CZTI data showed the detection of a short GRB 180618A, which was also detected by  Swift (LaPorte S. J. et al., GCN 22790), Fermi-GBM (Hamburg R. et al., GCN 22794), Konus-Wind (Svinkin D. et al., GCN 22822).

The source was clearly detected in the 40-200 keV energy range. The light curve shows a single peak of emission with peak at 00:43:13.5 UT. The measured peak count rate is 217.1 cts/s above the background in combined data of four quadrants, with a total of 140.9 cts. The local mean background count rate was 456.9 cts/s. Using cumulative rates, we measure a T90 of 2.1 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: GRB180620A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22843
SUBJECT: GRB 180620A: AstroSat CZTI detection
DATE:    18/06/25 15:56:07 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:

Analysis of Astrosat CZTI data showed the detection of a long GRB 180620A, which was also detected by Swift (Evans P. A. et al., GCN 22798) and Konus-Wind (D. Svinkin D. et al., GCN 22824).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 08:35:08.5 UT. The measured peak count rate is 287.9 cts/s above the background in combined data of four quadrants, with a total of 2046 cts. The local mean background count rate was 503 cts/s. Using cumulative rates, we measure a T90 of 14.8 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: GRB180620B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22844
SUBJECT: GRB 180620B: AstroSat CZTI detection
DATE:    18/06/25 15:56:59 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

V. Sharma, A. Vibhute and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:

Analysis of Astrosat CZTI data showed the detection of a long GRB 180620B, which was also detected by Swift (Evans P. A. et al., GCN 22807), Fermi-GBM (Mailyan B. et al., GCN 22813), Konus-Wind (Svinkin D. et al., GCN 22825).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 15:50:37.5 UT. The measured peak count rate is 259.6 cts/s above the background in combined data of four quadrants, with a total of 2643 cts. The local mean background count rate was 582.3 cts/s. Using cumulative rates, we measure a T90 of 22.3 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: GRB180624A
Detection_method: correction
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22845
SUBJECT: GRB 180624A: LBT/MODS redshift measurement
DATE:    18/06/25 18:25:52 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

A. Rossi (INAF-OAS), A. Gargiulo (INAF/IASF Milano), D. B. Malesani 
(DAWN/NBI and DARK/NBI), S. D. Vergani (GEPI/Obs. Paris), V. D'Elia 
(ASDC), S. Campana (INAF-OAB), report on behalf of the CIBO collaboration:

We observed the field of GRB 180624A (Swift trigger 844192; Gibson et 
al., GCN 22832) with the Multi-Object Double Spectrographs (MODS) 
instrument mounted on the 2x8.4-m LBT telescope (Mt Graham, AZ, USA). 
Images were obtained starting at 10:15 UT on 2018-06-25, 20.5 hr after 
the  GRB trigger.

Inspection of the 60 s acquisition image reveals a point source within 
the Swift/XRT enhanced error circle (Evans et al., GCN 22835), at 
coordinates:

RA(J2000) = 21:12:23.378
Dec(J2000)= -02:20:17.30

with an uncertainty of 0.2" in each coordinate, which is consistent with 
the source reported by Guidorzi et al. (GCN 22839). The source has 
magnitude r' = 20.6 +- 0.1 (AB), calibrated against r'-band SDSS field 
stars, and it is not visible in Pan-STARRS images, thus clearly singling 
it out as the afterglow.

Spectroscopy of the source was obtained for a total of 2x600 s, covering 
the wavelength range 3200-10000 AA. A broad trough is well visible 
centered around 4700 AA, which we identify as a DLA feature at z ~ 2.86. 
Detection of several absorption features, which we interpret as due to, 
among others, Si II, C IV, Al II, Al III, Fe II, allows to precisely 
measure the redshift to be z = 2.855, which we consider to be the 
redshift of GRB 180624A.

We also note the presence of a close-by and fainter galaxy, which is 
also visible in the Pan-STARRS images, 2.5" NW of the afterglow, at 
position:
RA(J2000) = 21:12:23.244
Dec(J2000)= -02:20:15.76
possibly consistent with the extended source reported by Schady (GCN 
22840). Given the measured redshift, we do not consider this object as 
related to the GRB, as it would have an unreasonable brightness and 
large separation at z = 2.8.

No correction for the expected Galactic foreground extinction, 
corresponding to a reddening of E_(B-V) = 0.05 mag in the direction of 
the burst (Schlafly & Finkbeiner 2011), has been applied.

We acknowledge the excellent support from the LBT-INAF staff, 
particularly Olga Kuhn and Steve Allanson in obtaining these observations.


GRB_name: GRB180624A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22846
SUBJECT: GRB 180624A: RATIR Optical Observations 
DATE:    18/06/25 22:16:14 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Eleonora Troja (GSFC), Nat Butler (ASU),
Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer
(UNAM), Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB),
Antonino Cucchiara (UVI), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz
(UCSC), JesÃºs GonzÃ¡lez (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Harvey
Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki
Toy (UMD) report:

We observed the field of GRB 180624A (Gibson et al., GCN Circ. 22832)
with the Reionization and Transients Infrared Camera (RATIR;
www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio
AstronÃ³mico Nacional on Sierra San Pedro MÃ¡rtir from 2018/06 25.26 to
2018/06 25.47 UTC (16.42 to 21.45 hours after the BAT trigger),
obtaining a total of 3.91 hours exposure in the r and i bands.

We detect a source in the enhanced Swift-XRT error circle (Goad et al.,
GCN Circ. 22835) with the following magnitudes:

  r = 21.03 +/- 0.02
  i = 20.45 +/- 0.01

These magnitudes are calibrated against the SDSS DR9 catalog, are in the
AB system, and are not corrected for Galactic extinction in the
direction of the GRB.

We note that the source has faded significantly from the earlier
observations of Guidorzi et al. (GCN Circ. 22839) of r = 19.9 +/- 0.1 at
0.54 hours and Schady (GCN Circ. 22840) of r = 20.2 +/- 0.1 at 15.07
hours. We also see the source fade by about 0.5 mag in each our bands
during the course of our observations.

We confirm the observation of Rossi et al. (GCN Circ. 22845) that the
source is a couple of arcsec to the SE of the SDSS galaxy
J211223.25-022015.9.

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


GRB_name: GRB180624A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22848
SUBJECT: GRB 180624A: Swift-BAT refined analysis
DATE:    18/06/26 02:19:59 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

J. R. Cummings (CPI), S. D. Barthelmy (GSFC),
S. L. Gibson (U Leicester), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 180624A (trigger #844192)
(Gibson et al., GCN Circ. 22832).  The BAT ground-calculated position is
RA, Dec = 318.096, -2.356 deg which is
  RA(J2000)  =  21h 12m 22.9s
  Dec(J2000) = -02d 21' 21.0"
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 47%.

The mask-weighted light curve shows a multi-peaked light curve that starts
at ~T-60 s and ends at ~T+540 s. The largest peak occurs at ~T+7 s. The
burst went out of the BAT FOV at ~T+720 s. T90 (15-350 keV) is 486.4 +- 38.5 sec
(estimated error including systematics).

The time-averaged spectrum from T-60.61 to T+541.80 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.91 +- 0.10.  The fluence in the 15-150 keV band is 5.8 +- 0.3 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+6.02 sec in the 15-150 keV band
is 1.4 +- 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/844192/BA/


GRB_name: GRB180623B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22849
SUBJECT: GRB 180623B: CALET Gamma-Ray Burst Monitor detection
DATE:    18/06/26 06:05:31 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

S. Nakahira (RIKEN), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita,
Y. Kawakubo, A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita,
Y. Sone (AGU), K. Yamaoka (Nagoya U), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), W. Ishizaki (ICRR),
M. L. Cherry (LSU), S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long GRB 180623B (Fermi-GBM trigger #551478155;
INTEGRAL SPI-ACS trigger #8082; Konus-Wind trigger
time on 20:22:36.97) triggered the CALET Gamma-ray Burst
Monitor (CGBM) at 20:22:36.598 UTC on 23 June 2018.
The burst signal was seen by all CGBM detectors.  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-3.5 sec, peaks at T+4.5 sec and ends at T+11.6 sec.
The T90 and the T50 durations measured by the SGM data are
12.0 +- 1.1 sec and 5.1 +- 0.5 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1213820487

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


GRB_name: GRB180626A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22850
SUBJECT: GRB 180626A: Swift detection of a burst with an optical counterpart
DATE:    18/06/26 08:34:26 GMT
FROM:    Kim Page at U.of Leicester  <klp5@leicester.ac.uk>

P. A. Evans (U Leicester), A. P. Beardmore (U Leicester),
J.D. Gropp (PSU), H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC) and
K. L. Page (U Leicester) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 08:21:16 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180626A (trigger=844615).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 243.567, +14.764 which is 
   RA(J2000) = 16h 14m 16s
   Dec(J2000) = +14d 45' 52"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multi-peaked
structure with a duration of about 50 sec.  The peak count rate
was ~3400 counts/sec (15-350 keV), at ~-2 sec after the trigger. 

The XRT began observing the field at 08:23:16.9 UT, 120.0 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 243.57544, 14.75598 which is equivalent
to:
   RA(J2000)  = 16h 14m 18.11s
   Dec(J2000) = +14d 45' 21.5"
with an uncertainty of 3.6 arcseconds (radius, 90% containment). This
location is 41 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 http://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 (3.47 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.2
(+2.28/-2.05) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 123 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 16:14:18.12 = 243.57551
  DEC(J2000) = +14:45:25.5  =  14.75707
with a 90%-confidence error radius of about 0.81 arc sec. This position is 5.1
arc sec. from the center of the XRT error circle. The estimated magnitude is
20.71 with a 1-sigma error of about  0.23. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.04. 

Burst Advocate for this burst is P. A. Evans (pae9 AT star.le.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB180626A
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22851
SUBJECT: GRB 180626A:  A long GRB detected by INTEGRAL
DATE:    18/06/26 09:34:14 GMT
FROM:    Diego Gotz at CEA  <diego.gotz@cea.fr>

D.Gotz (CEA, Saclay), S.Mereghetti (IASF-Milano), C.Ferrigno, E. Bozzo, V.Savchenko (ISDC, Versoix), L. Ducci (IAAT/ISDC) and J.Borkowski (CAMK, Torun) on behalf of the IBAS Localization Team report:

a gamma ray burst lasting about 40 s has been detected by IBAS in the IBIS/ISGRI data at 08:21:04  UT of June 26, 2018

The refined coordinates (J2000) are:

R.A.= 243.5715  deg
DEC.= 14.7486   deg
with an uncertainty of  1.1   arcmin (90% c.l.).

The burst had a measured peak flux of about 2.7 counts/cm2/s (20-200 keV, 1-s integration time) and a fluence in the same energy range of about 2e-6 erg/cm2. We note that both those values are lower limits, due to telemetry saturation at satellite level.
This burst was also detected by the Swift/BAT, XRT and UVOT (Evans et al., GCN 22850), and the IBIS position is at 33 arc seconds from the UVOT one.

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


GRB_name: GRB180626A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22852
SUBJECT: GRB 180626A: Enhanced Swift-XRT position
DATE:    18/06/26 10:07:10 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 804 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 180626A, 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 = 243.57603, +14.75692 which is equivalent
to:

RA (J2000): 16h 14m 18.25s
Dec (J2000): +14d 45' 24.9"

with an uncertainty of 1.8 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: GRB180626A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22853
SUBJECT: GRB 180626A: ISON-MN optical observations
DATE:    18/06/26 11:25:47 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

L. Elenin (KIAM), E. Mazaeva (IKI),  A. Pozanenko (IKI),  A. Volnova 
(IKI), I. Molotov (KIAM) report on behalf of larger GRB  follow-up 
collaboration:

We observed the field of  the Swift GRB 180626A  (Evans et al., GCN 
22850) with ISON-NM observatory. Observation started 51 s after burst 
trigger. We do not find optical afterglow (Evans et al., GCN  22850) in 
a combined image of first 5 frames. Preliminary photometry of the filed 
is following.


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

2018-06-26  08:22:07 0.00146  CR    5* 20  n/d  n/d    17.3

The photometry is based on several nearby USNO-B1.0 stars.


GRB_name: GRB180626A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22854
SUBJECT: GRB 180626A: LCO Haleakala observations
DATE:    18/06/26 12:13:43 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

R. Martone, C. Guidorzi (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell 
(U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU), A. Cucchiara 
(U. of Virgin Islands) on behalf of a large collaboration report:

The LCO 2-m unit at Haleakala Observatory (Hawaii), former FTN, began 
observing Swift and INTEGRAL GRB 180626A (Evans et al. GCN 22850; Gotz 
et al. GCN 22851) on June 26, 08:41:11 UT (20 min after the GRB trigger 
time) with the SDSS ri filters. The optical counterpart (Evans et al.) 
is clearly detected with the following magnitudes:

Mid Time since GRB Exposure Filter Magnitude
(hrs) (s)
------------------------------------------------------------------
0.424 5x120 SDSS-R 20.96 +- 0.12
0.617 5x120 SDSS-I 20.53 +- 0.12
------------------------------------------------------------------

as calibrated against nearby SDSS objects.


GRB_name: GRB180626A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22855
SUBJECT: GRB 180626A: RATIR Optical Detection
DATE:    18/06/26 12:36:12 GMT
FROM:    Eleonora Troja at GSFC  <eleonora.troja@nasa.gov>

Eleonora Troja (GSFC), Nat Butler (ASU), Alan M. Watson (UNAM),
Alexander Kutyrev (GSFC), William H. Lee (UNAM), Michael G. Richer (UNAM),
Ori Fox (STScI), J. Xavier Prochaska (UCSC), Josh Bloom (UCB),
Antonino Cucchiara (UVI), Owen Littlejohns (ASU), Enrico
Ramirez-Ruiz (UCSC), Jesus Gonzalez (UNAM), Carlos Roman-Zuniga (UNAM),
Harvey Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.),
and Vicki Toy (UMD) report:

We observed the field of GRB 180626A (Evans, et al., GCN 22850) with the
Reionization and Transients Infrared Camera (RATIR; www.ratir.org) on the
1.5m Harold Johnson Telescope at the Observatorio Astronomico Nacional on
Sierra San Pedro Martir from 2018/06 26.42 to 2018/06 26.43 UTC (1.61
to 2.06 hours after the BAT trigger), obtaining a total of 0.36 hours
exposure in the r and i bands.

For a source at the position of the UVOT counterpart, in comparison
with the SDSS DR9 catalog, we obtain the following detections:

   r    = 21.57 +/- 0.22
   i    = 20.91 +/- 0.13

These magnitudes are in the AB system and are not corrected for Galactic
extinction in the direction of the GRB. These magnitudes are fainter
than the values reported by Martone et al. (GCN 22854) suggesting that
the source is indeed the fading GRB afterglow.

We thank the staff of the Observatorio Astronomico Nacional in San Pedro
Martir.


GRB_name: GRB180623A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22856
SUBJECT: Konus-Wind observation of GRB 180623A
DATE:    18/06/26 12:44:39 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:

The long-duration GRB 180623A
(Swift detection: Page et al., GCN Circ. 22828;
Swift-BAT refined analysis: Barthelmy et al., GCN Circ. 22833)
triggered Konus-Wind at T0=60141.775 s UT (16:42:21.775).

The burst light curve shows a multipeaked structure
started at ~T0-69 s with a total duration of ~114 s.
The emission is seen up to ~2 MeV.

As observed by Konus-Wind, the burst
had a fluence of 3.15(-0.24,+0.28)x10^-5 erg/cm2,
and a 64-ms peak flux, measured from T0+2.208 s,
of 2.94(-0.98,+1.01)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+49.408 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 = -1.03(-0.16,+0.17)
and Ep = 233(-33,+48) keV (chi2 = 63/70 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.1
(chi2 = 61/69 dof).

The spectrum near the maximum count rate
(measured from T0+0.256 to T0+8.448 s)
is best fit in the 20 keV - 4 MeV range
by a power law with exponential cutoff model
with  alpha = -0.78(-0.17,+0.19)
and Ep = 390(-63,+91) keV (chi2 = 59/70 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.3
(chi2 = 59/69 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB180623_T60141/

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


GRB_name: GRB180626A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22857
SUBJECT: GRB 180626A: Swift/UVOT Detection
DATE:    18/06/26 15:22:56 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>

A. A. Breeveld (UCL-MSSL) and P. A. Evans (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180626A 
123 s after the BAT trigger (Evans et al., GCN Circ. 22850).
A fading source consistent with the XRT position (Osborne et al. GCN 
Circ. 22852) and also seen by Martone et al. (GCN Circ. 22854) and Troja 
et al. (GCN Circ. 22855) is detected in the initial UVOT exposures.

Preliminary detections and 3-sigma upper limits using the UVOT 
photometric system (Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for 
the finding chart (FC) and early exposures are:

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

white_FC           123          273          147         20.57 Â± 0.22
white              633         1033          190        >21.4
v                  665         6473          452        >20.2
b                  591         5858          246        >20.4
u                  336         6936          529        >20.7
w1                 714         6882          432        >21.0
m2                5043         6677          393        >20.1
w2                 641         6268          432        >21.3

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 0.04 in the direction of the 
burst (Schlegel et al. 1998).


GRB_name: GRB180624A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22858
SUBJECT: GRB 180624A: LCO Haleakala observations
DATE:    18/06/26 15:32:43 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi, R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell 
(U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU), A. Cucchiara, 
D. Morris (U. of Virgin Islands) on behalf of a large collaboration report:

The LCO 2-m unit at Haleakala Observatory (Hawaii) observed the optical 
afterglow of Swift GRB 180624A (Gibson et al. GCN 22832) on June 25, 
from 13:02 to 13:14 UT (0.97 days after the GRB trigger time) with the 
SDSS r filter. The source is detected with a magnitude of 21.44 +- 0.10 
(AB). Compared with previous reports (Guidorzi et al. GCN 22839; Schady 
GCN 22840; Rossi et al. GCN 22845; Watson et al. GCN 22846) we confirm 
that the source's decay has significantly steepened from ~0.6 to ~1.0 
days, as first noted by Watson et al.


GRB_name: GRB180626A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22859
SUBJECT: GRB 180626A: COATLI Optical Detection 
DATE:    18/06/26 17:10:10 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), William
H. Lee (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Alexander Kutyrev (GSFC), and
Eleonora Troja (GSFC) report:

We observed the field of GRB 180626A (Evans et al., GCN 22850) with the
COATLI 50-cm telescope and interim imager at the Observatorio
AstronÃ³mico Nacional on the Sierra de San Pedro MÃ¡rtir
(http://coatli.astroscu.unam.mx) from 2018-06-20 08:21:50.6 to
11:18:41.7 UTC (from 33.7 seconds after the trigger or 17.9 seconds
after the alert to 2.95 hours after the trigger), obtaining a total of
7020 seconds of exposure in the w filter.

Within the enhanced XRT error region (Osborne et al., GCN Circ. 22852),
we detect the afterglow previously reported by Evans et al. (GCN Circ.
22850), Martone et al. (GCN Circ. 22854), and Breeveld et al. (GCN Circ.
22857) with

  w = 21.4 +/- 0.9

In our first set of 30 images each of 5 seconds of exposure, from
08:21:50.6 to 08:27:10.1 UTC, we do not detect the afterglow with a
10-sigma limiting magnitude of

  w > 19.2

These magnitudes are calibrated against the Pan-STARRS1 catalog and the
USNO-B1 catalog (adjusted to an approximate AB system) and are not
corrected for Galactic extinction in the direction of the GRB.

We thank the COATLI technical team (Fernando Ãngeles, Oscar Chapa,
Salvador Cuevas, Alejandro Farah, Jorge Fuentes, RosalÃ­a Langarica,
Fernando QuirÃ³s, and Carlos Tejada) and the staff of the Observatorio
AstronÃ³mico Nacional.


GRB_name: GRB180626A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22860
SUBJECT: GRB 180626A: Swift-XRT refined Analysis
DATE:    18/06/26 18:28:59 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

D.N. Burrows (PSU), A.P. Beardmore (U. Leicester), S.L. Gibson (U.
Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo
(INAF-OAB), A. Tohuvavohu (PSU), S. J. LaPorte (PSU) and P.A. Evans
report on behalf of the Swift-XRT team:

We have analysed 6.6 ks of XRT data for GRB 180626A (Evans et al. GCN
Circ. 22850), from 129 s to 22.4 ks after the  BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position
for this burst was given by Osborne et al. (GCN Circ. 22852).

The light curve can be modelled with an initial power-law decay with an
index of alpha=0.21 (+0.14, -0.15), followed by a break at T+2992 s to
an alpha of 0.90 (+0.11, -0.10).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.01 (+/-0.11). The
best-fitting absorption column is  2.2 (+/-0.4) x 10^21 cm^-2, in
excess of the Galactic value of 3.5 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.5 x 10^-11 (4.9 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.2 (+/-0.4) x 10^21 cm^-2
Galactic foreground: 3.5 x 10^20 cm^-2
Excess significance: 8.0 sigma
Photon index:      2.01 (+/-0.11)

If the light curve continues to decay with a power-law decay index of
0.90, the count rate at T+24 hours will be 0.028 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.0 x
10^-12 (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/00844615.

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


GRB_name: GRB180626A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22861
SUBJECT: GRB 180626A: KAIT Optical Upper Limit
DATE:    18/06/26 19:58:36 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 180626A (Evans et al.,
GCN 22850; Gotz et al., GCN 22851) starting at 08:23:31 UT, 135 s
after the Swift/BAT trigger. Observations were performed with an
automatic sequence in the clear (roughly R), V, and I filters,
and the exposure time was 20 s per image. Since the INTEGRAL trigger
was received earlier than the Swift trigger, KAIT responed to the
INTEGRAL trigger first. Unfortunately the UVOT afterglow location
(Evans et al., GCN 22850) is outside our field of view for the first
few images. We later manually re-pointed to the UVOT afterglow location
starting at 08:52:10 UT about 30 minutes after the Swift/BAT trigger,
with the updated exposure time of 60 s per image.
We do not detect the afterglow at the reported UVOT location
(Evans et al., GCN 22850) in our single image, nor in the co-added
images. The typical limiting magnitude of our single clear image is
about 19.5 mag calibrated to the PS1 catalog.


GRB_name: GRB180626A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22862
SUBJECT: GRB 180626A: Swift-BAT refined analysis
DATE:    18/06/26 20:41:06 GMT
FROM:    Hans Krimm at NSF/NASA-GSFC  <hkrimm@nsf.gov>

H. A. Krimm (NSF/USRA), S. D. Barthelmy (GSFC),  J. R. Cummings (CPI), 
P. A. Evans (U Leicester),  A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):

Using the data set from T-239 to T+526 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 180626A (trigger #844615)
(Evans, et al., GCN Circ. 22850).  The BAT ground-calculated position is
RA, Dec = 243.569, 14.759 deg which is 
   RA(J2000)  =  16h 14m 16.6s 
   Dec(J2000) = +14d 45' 32.8" 
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 35%.

The mask-weighted light curve shows a multi-peaked structure.  The first peak 
is from approximately T-10 to T+5 sec, with a second overlapping peak from T+5 
to T+20 sec, followed by a weaker peak from T+20 to T+30 sec.
T90 (15-350 keV) is 30.07 +- 1.42 sec (estimated error including systematics).

The time-averaged spectrum from T-10.01 to T+25.59 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 1.64 +- 0.27, 
and Epeak of 47.7 +- 12.2 keV (chi squared 40.18 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 4.8 +- 0.2 x 10^-6 erg/cm2
and the 1-sec peak flux measured from T-3.69 sec in the 15-150 keV band is
4.1 +- 0.4 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 2.01 +- 0.06 (chi squared 46.26 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/844615/BA/


GRB_name: GRB180626B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22863
SUBJECT: IPN Triangulation of GRB 180626B (short)
DATE:    18/06/26 21:01:58 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

K. Hurley, on behalf of the IPN,

I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova,
and T. Cline on behalf of the Konus-Wind team,

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

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

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

The short-duration GRB 180626B was detected by
Konus-Wind, Mars-Odyssey (HEND), INTEGRAL (SPI-ACS),
and Swift (BAT) at about 6441 s UT (01:47:21).
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:
   214.555 (14h 18m 13s) +12.412 (+12d 24' 43")
  Corners:
   212.075 (14h 08m 18s)  +4.864 ( +4d 51' 52")
   213.948 (14h 15m 48s) +11.502 (+11d 30' 08")
   217.782 (14h 31m 08s) +21.164 (+21d 09' 51")
   215.173 (14h 20m 42s) +13.338 (+13d 20' 17")
  ---------------------------------------------
The error box area is 4.7 sq. deg, and its maximum
dimension is 17.2 deg (the minimum one is 29 arcmin).
The Sun distance was 109 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB180626_T06442/IPN/

The localization of this burst is inconsistent with that of the short 
burst GRB 180626C, which is being reported in the next GCN Circular.

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


GRB_name: GRB180626C
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22864
SUBJECT: IPN Triangulation of GRB 180626C (short)
DATE:    18/06/26 21:08:46 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova,
and T. Cline on behalf of the Konus-Wind team,

K. Hurley, on behalf of the IPN,

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

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

and

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

The short-duration GRB 180626C was detected by
Fermi (GBM; trigger 551697835), INTEGRAL (SPI-ACS), Konus-Wind,
and Swift (BAT), at about 33831 s UT (09:23:51).
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:
   278.579 (18h 34m 19s) +47.241 (+47d 14' 28")
  Corners:
   290.010 (19h 20m 02s) +48.528 (+48d 31' 40")
   290.186 (19h 20m 45s) +48.912 (+48d 54' 42")
   265.423 (17h 41m 42s) +43.214 (+43d 12' 49")
   264.736 (17h 38m 57s) +42.455 (+42d 27' 17")
  ---------------------------------------------
The error box area is 6.85 sq. deg, and its maximum
dimension is 18.81 deg (the minimum one is 22 arcmin).
The Sun distance was 106 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB180626_T33832/IPN

The localization of this burst is inconsistent with that of the short 
burst GRB 180626B, reported in GCN Circ. 22863.

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


GRB_name: GRB180626A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22865
SUBJECT: GRB 180626A: RATIR Optical Observations 
DATE:    18/06/27 05:11:57 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC),
William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J.
Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI),
Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz
(UCSC), JesÃºs GonzÃ¡lez (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Harvey
Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki
Toy (UMD) report:

We observed the field of GRB 180626A (Evans, et al., GCN Circ. 22850)
with the Reionization and Transients Infrared Camera (RATIR;
www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio
AstronÃ³mico Nacional on Sierra San Pedro MÃ¡rtir from 2018/06 27.16 to
2018/06 27.20 UTC (19.60 to 20.46 hours after the BAT trigger),
obtaining a total of 0.71 hours exposure in the r and i bands.

For a source at the position of the UVOT counterpart, in comparison with
the SDSS DR9 catalog, we obtain the following detections:

  r = 22.39 +/- 0.20
  i = 21.92 +/- 0.15

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

The source flux has faded approximately as t^-0.35 since our previous
observations (Troja et al., GCN Circ. 22855).

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


GRB_name: GRB180626B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22866
SUBJECT: Konus-Wind observation of GRB 180626B
DATE:    18/06/27 13:26:58 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:

The short-duration GRB 180626B
(IPN Triangulation: Hurley et al., GCN Circ. 22863)
triggered Konus-Wind at T0=6442.786 s UT (01:47:22.786).

The burst light curve shows a single pulse which starts
at ~T0-0.1 s and has a total duration of ~0.3 s.
The emission is seen up to ~2 MeV.

As observed by Konus-Wind, the burst
had a fluence of 7.69(-1.24,+1.35)x10^-7 erg/cm2,
and a 16-ms peak flux, measured from T0+0.004 s,
of 7.35(-2.79,+3.01)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+0.192 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 = -0.13(-0.54,+0.73)
and Ep = 218(-43,+60) keV (chi2 = 23/26 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.7
(chi2 = 23/25 dof).

The spectrum near the maximum count rate
(measured from T0 to T0+0.064 s)
is best fit in the 20 keV - 4 MeV range
by a power law with exponential cutoff model
with  alpha = -0.08(-0.59,+0.87)
and Ep = 294(-70,+116) keV (chi2 = 14/16 dof).
Fitting by a GRB (Band) model yields the same alpha and Ep,
and an upper limit on the high energy photon index: beta < -2.3
(chi2 = 14/15 dof).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB180626_T06442/

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


GRB_name: GRB180624A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22867
SUBJECT: GRB 180624A: NOT optical counterpart
DATE:    18/06/27 19:06:20 GMT
FROM:    Jonatan Selsing at DARK/NBI  <jselsing@dark-cosmology.dk>

Jonatan Selsing (DAWN/NBI), Kasper E. Heintz (Univ. Iceland and DAWN/NBI), Johan P. U.
Fynbo (DAWN/NBI), Daniele B. Malesani (DAWN/NBI and DARK/NBI), Jyri J. Lehtinen
(MPS), Teemu Willamo (Univ. of Helsinki), report on behalf of a larger
collaboration:

We observed the optical afterglow (Guidorzi, GCN #22839; Schady, GCN #22840;
Rossi et al., GCN #22845; Watson et al., GCN #22846; Guidorzi et al., GCN
#22858) of GRB 180624A (Gibson et al., GCN #22832) with the 2.5-m Nordic Optical
Telescope (NOT) equipped with StanCam.

Observations were carried out in the Bessel R filter, but calibrated against
Pan-STARRS r-band local photometry, using the transformations of Lupton (2005).
An optical afterglow is detected at a position consistent with previous reports.

At a mid time 11.0 hr after the BAT trigger, we measure for the counterpart R =
20.10 +- 0.04 (Vega). This measurement has not been corrected for Milky Way
extinction (A_V = 0.13). Due to the vicinity of the nearby galaxy noted by
Schady (GCN #22840), Guidorzi et al. (GCN #22858), and Rossi et al. (GCN 22845),
we cannot exclude some minor contamination from this object to the afterglow
photometry.


GRB_name: GRB180626C
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22868
SUBJECT: Konus-Wind observation of GRB 180626C
DATE:    18/06/28 11:22:16 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Tsvetkova, A. Lysenko, and T. Cline
on behalf of the Konus-Wind team, report:

The short-duration GRB 180626C
(IPN triangulation: Svinkin et al., GCN 22864)
triggered Konus-Wind at T0=33832.424 s UT (09:23:52.424).

The burst light curve shows a single pulse
which starts at T0-40 ms and has a total duration of ~340 ms.

As observed by Konus-Wind, the burst
had a fluence of 6.13(-1.15,+2.18)x10^-7 erg/cm2,
and a 16-ms peak flux, measured from T0-0.032 s,
of 7.87(-2.06,+3.15)x10^-6 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

Since the most intense part of the burst was detected before
the trigger, the spectral analysis was performed using
the KW 3-channel light curve data.

Modeling the KW 3-channel time-integrated spectrum
(from T0-0.04 s to T0+0.336 s)
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
yields alpha = -0.87 (-0.23,+0.31), and Ep = 406 (-113,+225) keV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB180626_T33832/

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


GRB_name: GRB180626A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22869
SUBJECT: Konus-Wind observation of GRB 180626A
DATE:    18/06/29 10:49:02 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R.Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lysenko,
and T. Cline on behalf of the Konus-Wind team, report:

The long GRB 180626A (Swift-BAT trigger #844615: Evans et al.,
GCN 22850; Krimm et al., GCN 22862;
INTEGRAL detection: Gotz et al., GCN 22851)
was detected by Konus-Wind (KW) in the waiting mode.

The burst light curve shows a single emission episode
with a duration of ~ 36 s.

As observed by KW, the burst had a fluence of
7.21(-0.79,+0.97)x10^-6 erg/cm2 and a 2.944-s peak flux,
measured from ~T0(BAT)-3.841 s, of 3.92(-0.49,+0.58)x10^-7 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

Modeling the KW 3-channel time-integrated spectrum
(from ~T0(BAT)-9.7 s to ~T0(BAT)+25.6 s)
by a simple power-law model yields a power law
index of -2.19(-0.04,+0.05), chi2 = 2.5/1 dof.

The KW light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB180626A/

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


GRB_name: GRB180626A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22870
SUBJECT: GRB 180626A: TSHAO optical upper limit
DATE:    18/06/29 16:09:33 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), A. Pozanenko (IKI),  A. Kusakin (FAPHI), I. Reva 
(FAPHI),  A. Volnova (IKI), M. Krugov (FAPHI) report on behalf of larger 
GRB follow-up collaboration:

We observed the field of GRB 180626A  (Evans et al., GCN 22850; Gotz  et 
al., GCN 22851)   with Zeiss-1000 1-m telescope of Tien Shan 
Astronomical Observatory starting on June 26 (UT) 16:26:21. We obtained 
several images in R-filter.  The optical afterglow (Evans et al., GCN 
22850;  Martone et al. GCN 22854; Troja et al. GCN 22855; Watson et al. 
GCN 22859)  is not detected in a stacked image. Preliminary photometry 
of the field is following.

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

2018-06-26  16:26:21 0.41918  R      99*120  n/d  n/d    21.5

The photometry is based on several nearby SDSS-DR10 stars.

Ref.stars
SDSS-DR9_id            R(Lupton)
J161422.32+144433.2    15.113
J161357.84+144752.0    13.989
J161440.94+144745.0    13.136


GRB_name: GRB180626C
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22871
SUBJECT: GRB 180626C: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 551697835)
DATE:    18/06/30 03:46:01 GMT
FROM:    Michael Coughlin at Caltech/LIGO  <mcoughli@caltech.edu>

Michael W. Coughlin (Caltech), Leo P. Singer (NASA GSFC), TomÃ¡s Ahumada
(UMD), S. Bradley Cenko (NASA GSFC), Shaon Ghosh (UWM), Mansi M. Kasliwal
(Caltech), Eric C. Bellm (UW), V. Zach Golkhou (UW), Ludwig Rauch (DESY),
Robert Stein (DESY), on behalf of the ZTF and GROWTH collaborations and the
KPED team

We observed the localization region of the short GRB 180626C (trigger
551697835) detected by the Gamma-Ray Burst Monitor (GBM) on the Fermi
satellite with the Palomar 48 inch telescope equipped with the 47 square
degree Zwicky Transient Facility (ZTF) camera. We obtained a series of r-
and g-band images covering 275 square degrees beginning at 10:52 UT on 2018
June 26 (1:29 hours after the burst trigger time), corresponding to ~ 36%
of the probability enclosed in the localization region.  Using the IPN
updated localization of GRB 180626C available the next day, we observed the
new region with ZTF beginning at 05:01 UT on 2018 June 27 (19:43 hours
after the trigger time). The observations covered 230 square degrees,
corresponding to ~ 87% of the probability enclosed in the localization
region.

The images were processed through the ZTF reduction and image subtraction
pipelines at IPAC to search for potential counterparts. 45
high-significance transient and variable candidates were identified by our
pipeline in the area observed, all of which had previous detections with
ZTF in the days and weeks prior to the GRB trigger time (e.g., supernovae,
active galactic nuclei). Out of the 45 transients, only 1 transient was
within the IPN localization region, but the object has previous detections
at similar magnitudes. No viable optical counterparts were thus identified.

We would like to highlight one interesting object discovered in the ZTF
fields on the first night (it does not fall into the IPN localization
region) and later followed up with the Kitt Peak EMCCD Demonstrator (KPED)
on the Kitt Peak 84 inch telescope on June 27. Located at RA: 19:48:49.1 ,
DEC: +46:30:36.1, ZTF18aauebur was first detected by ZTF June 25.30 (1 day
before the trigger); it is a rapidly evolving transient that has gone from
g = 18.4 to g = 20.5 in 1.92 days.  An underlying source is present at this
location in Pan-STARRS DR1 and GALEX. Given the low Galactic latitude, it
may be a stellar flare.

The median 5 sigma upper limit for an isolated point source in our images
was r > 20.9 and g > 20.9 mag for the observations made on June 26 and r >
21.2 and g > 21.0 mag for the observations made on June 27.

ZTF is a project led by PI S. R. Kulkarni at Caltech (see ATEL #11266
<http://www.astronomerstelegram.org/?read=11266>), and includes IPAC; WIS,
Israel; OKC, Sweden; JSI/UMd, USA; UW, USA; DESY, Germany; NRC, Taiwan; UW
Milwaukee, USA and LANL USA. ZTF acknowledges the generous support of the
NSF under AST MSIP Grant No 1440341. Alert distribution service provided by
DIRAC@UW. Alert filtering is being undertaken by the GROWTH marshal system,
supported by NSF PIRE grant 1545949.

[GCN OPS NOTE(01jul18): Per author's request, the "A"s in the Subject-line
and in the two places in the first paragraph were changed to "C"s.  And the
Trigger number in the Subject-line was changed to 551697835.]


GRB_name: GRB180630A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22872
SUBJECT: GRB 180630A: Swift detection of a burst with an optical counterpart
DATE:    18/06/30 11:23:40 GMT
FROM:    Caryl Gronwall at PSU/Swift-UVOT  <caryl@swift.psu.edu>

P. D'Avanzo (INAF-OAB), C. Gronwall (PSU), J.D. Gropp (PSU),
J. A. Kennea (PSU), H. A. Krimm (NSF/USRA), F. E. Marshall (NASA/GSFC)
and T. Sakamoto (AGU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 11:11:51 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180630A (trigger=845443).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 48.810, -87.482 which is 
   RA(J2000) = 03h 15m 14s
   Dec(J2000) = -87d 28' 54"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single-peaked
structure with a duration of about 10 sec.  The peak count rate
was ~6500 counts/sec (15-350 keV), at ~4 sec after the trigger. 

The XRT began observing the field at 11:13:13.4 UT, 81.6 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source located at RA, Dec 48.95887, -87.47850 which
is equivalent to:
   RA(J2000)  = 03h 15m 50.13s
   Dec(J2000) = -87d 28' 42.6"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). This
location is 26 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 http://www.swift.ac.uk/sper.  We
cannot determine whether the source is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 1.34
x 10^21 cm^-2 (Willingale et al. 2013). 

The initial flux in the 2.5 s image was 6.12e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 87 seconds after the BAT trigger. There is a candidate afterglow in
the rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 03:15:56.02 =  48.98342
  DEC(J2000) = -87:28:42.4  = -87.47844
with a 90%-confidence error radius of about 0.62 arc sec. This position is 5.7
arc sec. from the center of the XRT error circle. The estimated magnitude is
17.44 with a 1-sigma error of about  0.14. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.13. 

Burst Advocate for this burst is P. D'Avanzo (paolo.davanzo AT brera.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/too.html.)


GRB_name: GRB180630A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22873
SUBJECT: GRB 180630A: Enhanced Swift-XRT position
DATE:    18/06/30 15:42:40 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 1171 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 180630A, 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 = 48.98081, -87.47880 which is equivalent
to:

RA (J2000): 03h 15m 55.39s
Dec (J2000): -87d 28' 43.7"

with an uncertainty of 1.7 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: GRB180626C
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22874
SUBJECT: GRB 180626C / Fermi trigger 551697835: MASTER inspection
DATE:    18/06/30 16:18:31 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, V.Kornilov,  N.Tiurina, A.Kuznetsov, V.Chazov,
I. Gorbunov, D. Vlasenko, D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov
Lomonosov Moscow State University,SAI

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias

A. Tlatov, V.Senik, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

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

H.Levato, 
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

D. Buckley
South African Astronomical Observatory

O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University

A. Gabovich, V. Yurkov, Yu. Sergienko
Blagoveschensk Educational State University, Blagoveschensk



MASTER-IAC robotic telescope (MASTER-Net: http://observ.pereplet.ru Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) ,
located in Teyde Observatory (IAC, Spain),
was pointed to the IPN (Svinkin et al. GCN22864, Kozlova et al. GCN22868) Triangulation GRB180626C / Fermi trigger 551697835 
(GRB_Time  18/06/26 09:23:50.65UT; RA,Dec(2000)=19h 00m 14s +44d 49' 12" (GRB_ERROR: 8.21 deg radius, statistical only  , see 
https://gcn.gsfc.nasa.gov/other/551697835.fermi) also inspected by ZTF (Coughlin et al. GCN22871)
  at 2018-06-26 21:37:30UT-22:53:48 with unfiltered  mlim=19.1 (180s expositions);
2018-06-27 03:34:57-03:53:20 with mlim=19.7 on summary expositions (5sigma, exp=540s).
The observations started on zenit distance = 41 degrees.  The sun  altitude  was -17.66 degree.

MASTER-SAAO  robotic telescope located in South Africa started Fermi 
inspection  5834 sec after notice time and 37433 sec after trigger time at  2018-06-26 19:51:28 UT.
The 5-sigma upper limit on our second (180s exposure)  set is about 16.2mag.
The observations started on zenit distance = 89 degrees, galaxy latitude b = 22 degree.
The moon (98 % bright part) is 64 degrees above the horizon. The distance 
between  moon and  object is 69. The sun  altitude  was -52.2 degree.


MASTER-Amur robotic telescope, located at BSPU, was pointed to Fermi 
trigger 551697835 on 2018-06-27 14:09:39UT, and observed till  14:57:32.584UT with mlim=18.0(180s exp)

MASTER-Kislovodsk robotic telescope, located at Kislovodsk Solar Station 
of Pulkovo observatory, started Fermi trigger inspection at 2018-06-27 20:53:26 UT.
The 5-sigma upper limit on our first (180s exposure)  set is about 18.8mag .
The observations started on zenit distance =  6 degrees, galaxy latitude b = 22 degree.
The moon (100 % bright part) is 26 degrees above the horizon. The distance 
between  moon and  object is 68 .The sun  altitude  is -22.8 degree.

New OT, that could be connected with GRB, wasn't found.


GRB_name: GRB180630A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22875
SUBJECT: GRB 180630A: Fermi GBM detection
DATE:    18/06/30 16:54:15 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

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

"At 11:11:54.41 UT on 30 June 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180630A (trigger 552049919 / 180630467)
which was also detected by the Swift BAT and XRT instruments
(D'Avanzo et al. 2018, GCN 22872).
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 structured peak
with a duration (T90) of about 12 s (50-300 keV).
The time-averaged spectrum from T0-1.54s to T0+8.70 s is
best fit by a power law function with an exponential
high-energy cutoff. The power law index is -1.37 +/- 0.09 and
the cutoff energy, parameterized as Epeak, is 84 +/- 8 keV.
A Band function fits the spectrum equally well
with Epeak = 60 +/- 10 keV, alpha = -1.11 +/- 0.20,
and beta = -2.32 +/- 0.16.

The event fluence (10-1000 keV) in this time interval is
(2.5 +/- 0.1)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.15 s in the 10-1000 keV band
is 9.4 +/- 0.4 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB180630A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22876
SUBJECT: GRB 180630A: Swift-XRT refined Analysis
DATE:    18/06/30 21:33:37 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester), Z. Liu (NAOC /
U. Leicester), A. Melandri (INAF-OAB), V. D'Elia (ASDC), A. Tohuvavohu
(PSU), S. J. LaPorte (PSU), J.A. Kennea (PSU) and P. D'Avanzo report on
behalf of the Swift-XRT team:

We have analysed 6.3 ks of XRT data for GRB 180630A (D'Avanzo et al.
GCN Circ. 22872), from 87 s to 29.0 ks after the  BAT trigger. The data
comprise 69 s in Windowed Timing (WT) mode with the remainder in Photon
Counting (PC) mode. The enhanced XRT position for this burst was given
by Beardmore et al. (GCN Circ. 22873).

The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=3.04 (+0.61, -0.21). At T+155 s  the decay
flattens to an alpha of 0.25 (+0.26, -0.09). The light curve breaks
again at T+659 s to a decay with alpha=0.80 (+0.07, -0.05),  before a
final break at T+24.3 ks s after which the decay index is 4.4 (+3.6,
-2.2).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.91 (+0.21, -0.17). The
best-fitting absorption column is  consistent with the Galactic value
of 1.3 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has
a photon index of 1.64 (+/-0.12) and a best-fitting absorption column
of 1.7 (+0.5, -0.3) x 10^21 cm^-2. The counts to observed (unabsorbed)
0.3-10 keV flux conversion factor deduced from this spectrum  is 4.3 x
10^-11 (5.1 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.7 (+0.5, -0.3) x 10^21 cm^-2
Galactic foreground: 1.3 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.64 (+/-0.12)

If the light curve continues to decay with a power-law decay index of
4.4, the count rate at T+24 hours will be 4.3 x 10^-4 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.8 x
10^-14 (2.2 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/00845443.

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


GRB_name: GRB180630A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22877
SUBJECT: GRB 180630A: Swift-BAT refined analysis
DATE:    18/07/01 12:30:12 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), J. R. Cummings (CPI),
H. A. Krimm (NSF/USRA), C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(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 180630A (trigger #845443)
(D'Avanzo, et al., GCN Circ. 22872).  The BAT ground-calculated position is
RA, Dec = 48.885, -87.476 deg which is
    RA(J2000)  =  03h 15m 32.5s
    Dec(J2000) = -87d 28' 33.4"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 59%.
  
The mask-weighted light curve shows a double-peaked structure.  The first pulse
starts at T0, peaks at T+4 sec and ends at T+15 sec.  The second weak pulse
starts at T+15 sec and ends at T+30 sec.  T90 (15-350 keV) is 18.85 +- 6.45 sec
(estimated error including systematics).
  
The time-averaged spectrum from T-0.36 to T+30.02 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
2.07 +- 0.10.  The fluence in the 15-150 keV band is 1.8 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+3.65 sec in the 15-150 keV band
is 6.6 +- 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/845443/BA/


GRB_name: GRB180626B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22878
SUBJECT: GRB 180626B : GOTO optical observations
DATE:    18/07/01 21:14:54 GMT
FROM:    Danny Steeghs at U.of Warwick/GOTO  <D.T.H.Steeghs@warwick.ac.uk>

J.Lyman, D.Steeghs, K.Ulaczyk, A.Levan, B.Gompertz (U. Warwick),
N.Tanvir (U. Leicester), M.Dyer (U. Sheffield), K. Ackley, D.Galloway,
E.Rol (Monash U.), G.Ramsay (Armagh O.), V.Dhillon (U. Sheffield),
P.O'Brien (U. Leicester), S.Poshyachinda (NARIT),
D.Pollacco (U. Warwick), E.Thrane (Monash U.)

report on behalf of the GOTO collaboration:


In response to the short-duration GRB 180626B (GCN 22863, 22866), the
Gravitational-wave Optical Transient Observer (GOTO) observed the IPN
triangulation region as reported in Hurley et al. (GCN 22863).

Observations were spread over several telescope array pointings,
beginning 2018-06-26T21:52 UT (20.1 hours after the burst) and
employed sets of 3x120s exposures in our wide L filter (400-700nm).
Approximately 83% of the IPN region was covered on-chip. These fields
were repeated in subsequent nights to permit difference imaging
analysis and typically achieved a 5 sigma limiting magnitude of
V=19.9-20.1 (based on zeropoints derived from APASS crossmatching).

We made use of the GLADE galaxy catalog to pay particular attention to
possible source candidates near galaxies within 200 Mpc. No
significant sources that could be credibly associated with the GRB were
detected.

GOTO is operated at the La Palma observing facilities of the
University of Warwick on behalf of a consortium including the
University of Warwick, Monash University, Armagh Observatory, the
University of Leicester, the University of Sheffield, the National
Astronomical Research Institute of Thailand (NARIT) and the Instituto
de Astrofisica de Canarias (IAC)

https://goto-observatory.org/


GRB_name: GRB180626C
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22879
SUBJECT: GRB 180626C : GOTO optical observations
DATE:    18/07/01 21:15:44 GMT
FROM:    Danny Steeghs at U.of Warwick/GOTO  <D.T.H.Steeghs@warwick.ac.uk>

J.Lyman, D.Steeghs, K.Ulaczyk, A.Levan, B.Gompertz (U. Warwick),
N.Tanvir (U. Leicester), M.Dyer (U. Sheffield), K. Ackley, D.Galloway,
E.Rol (Monash U.), G.Ramsay (Armagh O.), V.Dhillon (U. Sheffield),
P.O'Brien (U. Leicester), S.Poshyachinda (NARIT),
D.Pollacco (U. Warwick), E.Thrane (Monash U.)

report on behalf of the GOTO collaboration:


In response to the short-duration GRB 180626C (GCN 22864, 22868,
22871, 22874), the Gravitational-wave Optical Transient Observer
(GOTO) observed the IPN triangulation region as reported in Svinkin et
al. (GCN 22864).

Observations were spread over several telescope array pointings,
beginning 2018-06-26T22:21 UT (13 hours after the burst) and employ
sets of 3x120s exposures in our wide L filter(400-700nm).
Approximately 95% of the IPN region was covered on-chip. These fields
were repeated in subsequent nights to permit difference imaging
analysis and typically achieved a 5 sigma limiting magnitude of
V=20.1-20.3 (based on zeropoints derived from APASS crossmatching).

We made use of the GLADE galaxy catalog to pay particular attention to
possible source candidates near galaxies within 200 Mpc. Similar to
the searches reported in Coughlin et al. (GCN 22871) and Lupinov et
al. (GCN 22874), we find no significant sources that could be credibly
associated with the GRB.


GOTO is operated at the La Palma observing facilities of the University
of Warwick on behalf of a consortium including the University of
Warwick, Monash University, Armagh Observatory, the University of
Leicester, the University of Sheffield, the National Astronomical
Research Institute of Thailand (NARIT) and the Instituto de Astrofisica
de Canarias (IAC)

https://goto-observatory.org/


GRB_name: GRB180701A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22880
SUBJECT: GRB 180701A: MAXI/GSC detection
DATE:    18/07/02 01:13:21 GMT
FROM:    H. Negoro at Nihon U.  <negoro@phys.cst.nihon-u.ac.jp>

MAXI/GSC detection of GRB 180701A/MAXI J2119-045

W. Maruyama, H. Negoro (Nihon U.),
T. Mihara, S. Nakahira, F. Yatabe, Y. Takao, M. Matsuoka (RIKEN), 
N. Kawai, M. Sugizaki, Y. Tachibana, K. Morita (Tokyo Tech), 
T. Sakamoto, M. Serino, S. Sugita, Y. Kawakubo, T. Hashimoto, 
A. Yoshida (AGU), M. Nakajima, A. Sakamaki (Nihon U.), S. Ueno, H. Tomida, 
M. Ishikawa, Y. Sugawara, N. Isobe, R. Shimomukai (JAXA), Y. Ueda, 
A. Tanimoto, T. Morita, S. Yamada (Kyoto U.), Y. Tsuboi, W. Iwakiri, R. Sasaki, 
H. Kawai, T. Sato (Chuo U.), H. Tsunemi, T. Yoneyama (Osaka U.), 
M. Yamauchi, K. Hidaka, S. Iwahori (Miyazaki U.), T. Kawamuro (NAOJ), 
K. Yamaoka (Nagoya U.), M. Shidatsu (Ehime U.) 

MAXI/GSC detected an uncatalogued short X-ray transient event at 06:47 UT 
on 2018 July 1. Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (319.919 deg, -4.500 deg) = (21 19 40, -04 30 00) (J2000) 
with a statistical 90% C.L. elliptical error region 
with long and short radii of 0.36 deg and 0.32 deg, respectively. 
The roll angle of the long axis from the north direction is 57.0 deg counterclockwise. 
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The X-ray flux averaged over the scan was 74 +- 19 mCrab
(4.0-10.0keV, 1 sigma error).
There was no significant excess flux in the previous transit at 05:14 UT
and in the next transit at 08:20 UT with an upper limit of 20 mCrab for each.

Due to the poor statistics, we could not obtain any useful information on 
the energy spectrum of the source.
The burst duration actually observed was about 10 seconds, which was, however, 
a lower limit of the duration for the event occurring at the beginning or end 
of the scan window. Note that, in such case, the error region to the scan 
direction is larger than that of the steady-flux-source case described above.

The nature of the source is quite unknown, then we refer to the source as 
GRB 180701A and MAXI J2119-045.


GRB_name: GRB180630A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22881
SUBJECT: GRB 180630A: Swift/UVOT Detection
DATE:    18/07/02 01:46:46 GMT
FROM:    Sam LaPorte at PSU  <sjl5346@psu.edu>

GRB 180630A: Swift/UVOT Detection

S. J. LaPorte (PSU) and P. D'Avanzo (INAF-OAB)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180630A
88 s after the BAT trigger (D'Avanzo et al., GCN Circ. 22872).
A fading source consistent with the XRT position
(Beardmore et al. GCN Circ. 22873)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  03:15:55.74 =  48.98224 (deg.)
    Dec (J2000) = -87:28:42.3  = -87.47842 (deg.)
with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence).

Preliminary detections and 3-sigma upper limits using the UVOT photometric
system
(Breeveld et al. 2011, AIP Conf. Proc. 1358, 373) for the early exposures are: 

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

white               88          237          148         17.49 +/- 0.04
white             6384         6584          196         19.50 +/- 0.11
v                  629         1597          117         18.56 +/- 0.20
b                  555          748           39         18.76 +/- 0.19
u                  300          549          246         17.76 +/- 0.06
w1                 678         7392          510         19.42 +/- 0.17
m2                 654         7187          452         20.16 +/- 0.33
w2                 605         6777          255        >19.9

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.13 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB180703A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22882
SUBJECT: GRB 180703A: Tiled Swift observations
DATE:    18/07/04 01:51:48 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Swift has initiated a series of observations, tiled on the sky, of the
Fermi/LAT GRB 180703A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00070

Any uncatalogued X-ray sources detected in this analysis will be
reported on this website and via GCN COUNTERPART notices. The probability of finding
serendipitous sources, unrelated to the Fermi/LAT 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: GRB180703A
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22883
SUBJECT: GRB 180703A: Fermi-LAT detection
DATE:    18/07/04 01:57:55 GMT
FROM:    Judith Racusin at GSFC  <judith.racusin@nasa.gov>

J. L. Racusin (NASA/GSFC), M. CrnogorÄeviÄ‡ (UMD), M. Axelsson (KTH and Stockholm Univ.), 
A. Barker (George Washington), G. Vianello (Stanford), and M. Arimoto (Kanazawa University), 
report on behalf of the Fermi-LAT team:

At 21:01:40.50 on July, 03, 2018 Fermi-LAT detected high-energy emission from GRB 180703A, 
which was also detected by Fermi-GBM (trigger 552344505 / 180703876).

The best LAT on-ground location is found to be
RA, Dec = 6.54, -67.1 (J2000)
with an error radius of 0.3 deg (90% containment, statistical error only).

This was 48 deg from the LAT boresight at the time of the trigger.

The data from the Fermi-LAT show a significant increase in the event rate that is spatially and temporally 
correlated with the trigger with high significance.

The highest-energy photon is a ~930 MeV event which is observed at 40 seconds after the GBM trigger.

A Swift ToO has been approved for this burst.

The Fermi-LAT point of contact for this burst is Judith Racusin (judith.racusin@nasa.gov).

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: GRB180703B
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22884
SUBJECT: GRB 180703B: Fermi-LAT detection
DATE:    18/07/04 02:35:47 GMT
FROM:    Judith Racusin at GSFC  <judith.racusin@nasa.gov>

J. L. Racusin (NASA/GSFC), M. CrnogorÄeviÄ‡ (UMD), A. Barker (George Washington), 
G. Vianello (Stanford),  M. Axelsson (KTH and Stockholm University) report on behalf 
of the Fermi-LAT team:

At 22:46:51.32 UTC on July 03, 2018 Fermi-LAT detected high-energy emission from 
GRB 180703B, which was also detected by Fermi-GBM (trigger 552350816 / 180703949).
The best LAT on-ground location is found to be

RA, Dec = 96.92, -29.88 (J2000)

with an error radius of 0.4 deg (90% containment, statistical error only). 

This was 30 deg from the LAT boresight at the time of the trigger.

The data from the Fermi-LAT show a significant increase in the event rate that is spatially 
and temporally correlated with the trigger with high significance. 

The highest-energy photon is a ~1 GeV event which is observed 35 seconds after the GBM 
trigger.

A Swift ToO has been requested for this burst. 

The Fermi-LAT point of contact for this burst is Judith Racusin (judith.racusin@nasa.gov).

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: GRB180704A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22885
SUBJECT: GRB 180704A: Swift detection of a burst
DATE:    18/07/04 05:47:20 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

E. Sonbas (Adiyaman Univ.), A. D'Ai (INAF-IASFPA),
K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of
the Neil Gehrels Swift Observatory Team:

At 05:36:42 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180704A (trigger=846088).  Swift did not immediately 
slew to the burst due to an Earth limb constraint. 
The BAT on-board calculated location is 
RA, Dec 32.638, +69.948 which is 
   RA(J2000) = 02h 10m 33s
   Dec(J2000) = +69d 56' 52"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a complex set
of peaks with a duration of about 25 sec.  The peak count rate
was ~4000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to an observing constraint, Swift will not slew until T0+48.1
minutes. There will be no XRT or UVOT data until this time. 

Burst Advocate for this burst is E. Sonbas (edasonbas AT yahoo.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/too.html.)


GRB_name: GRB180704A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22886
SUBJECT: GRB 180704A: MASTER optical observation
DATE:    18/07/04 06:33:15 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, V.Kornilov,  N.Tiurina, A.Kuznetsov, V.Chazov,
I. Gorbunov, D. Vlasenko, D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov
Lomonosov Moscow State University,SAI

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias (IAC)

A. Tlatov, V.Senik, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

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

H.Levato, Instituto de Ciencias Astronomicas, de la Tierra y del Espacio 
(ICATE)

D. Buckley
South African Astronomical Observatory

O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University

A. Gabovich, V. Yurkov, Yu. Sergienko
Blagoveschensk Educational State University, Blagoveschensk



MASTER-IAC robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
Spain (IAC Teide Observatory) was pointed to the Swift BAT GRB180704A 
(Sonbas et al. GCN 22885) 25 sec  after notice time and 41 sec after 
trigger time at 2018-07-04 05:37:23 UT. 
On our 10,20s exposure  set there is no optical transient  within SWIFT 
error-box (ra=32.6375 dec=69.9478 r=0.05).
The 5-sigma upper limit has been about 14.2mag
The message may be cited.


====================================================================



The observations made on zenit distance = 48 degrees, galaxy latitude b = 
8 degree.
The moon (70 % bright part) is 54 degrees above the horizon. The distance 
between  moon and  object is 83
Observations started at twilight.
The sun  altitude  is -7.5 degree, sunrise.


GRB_name: GRB180704A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22887
SUBJECT: GRB 180704A: Swift-XRT observations
DATE:    18/07/04 07:18:52 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

D.N. Burrows (PSU), J.A. Kennea (PSU), M. Perri (ASDC), G. Tagliaferri
(INAF-OAB), P.A. Evans (U. Leicester) and J.P. Osborne (U. Leicester)
report on behalf of the Swift-XRT team:

The XRT began observing the field of GRB 180704A at 06:26:11.9 UT,
2969.1 seconds after the BAT trigger. Using promptly downlinked data we
find an uncatalogued X-ray source with an enhanced position: RA, Dec
32.6592, 69.9641 which is equivalent to:
   RA(J2000)  = 02h 10m 38.22s
   Dec(J2000) = +69d 57' 50.7"
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This
location is 63 arcseconds from the BAT onboard position, within the BAT
error circle. This position may be improved as more data are received;
the latest position is available at http://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 4.92
x 10^21 cm^-2 (Willingale et al. 2013). 


GRB_name: GRB180703B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22888
SUBJECT: GRB 180703B: CALET Gamma-Ray Burst Monitor detection
DATE:    18/07/04 09:24:53 GMT
FROM:    Valentin Pal'shin at AGU  <val@phys.aoyama.ac.jp>

I. Takahashi (IPMU), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita,
Y. Kawakubo, A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita,
Y. Sone (AGU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The Fermi-LAT GRB 180703B (Racusin et al. GCN Circ. 22884) triggered
the CALET Gamma-ray Burst Monitor (CGBM) at 22:46:51.183 UTC on 3 July 2018.
The burst signal was seen by all CGBM detectors.

The burst light curve shows two short pulses which start at T+0.1 sec,
peaks at T+1.4 sec and ends at T+2.1 sec.  The T90 and the T50 durations
measured by the SGM data are 1.4 +- 0.2 sec and 0.4 +- 0.1 sec (40-1000 keV),
respectively.

Despite its very high brightness the burst spectrum is soft with almost
no emission seen in the CGBM data above ~500 keV. So, this is a very bright,
short, and soft GRB.
The follow-up observations of this interesting event is highly encouraged.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1214693124/

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


GRB_name: GRB150101B
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22889
SUBJECT: GRB150101B: INTEGRAL prompt gamma-ray signal from a possible GRB170817A-analogue
DATE:    18/07/04 10:24:47 GMT
FROM:    Carlo Ferrigno at IAAT/ISDC  <carlo.Ferrigno@unige.ch>

J. Rodi, A. Bazzano, P. Ubertini (IAPS-Roma)
E. Bozzo, C. Ferrigno, V. Savchenko (ISDC, University of Geneva, CH)
E. Kuulkers (ESTEC/ESA, The Netherlands)
D. Gotz (DRF/Irfu/DAp Saclay/CEA)
L. Hanlon, A. Martin-Carrillo (UCD, Ireland)
J. M. Mas-Hesse (CSIC-INTA, Spain)
S. Mereghetti (INAF IASF-Milano, Italy)
L. Natalucci (IAPS-Roma)
A. Lutovinov, R. Sunyaev (IKI, Russia)
report on behalf of the INTEGRAL Gravitational Wave Team

We have analyzed INTEGRAL archival data of the SPI-ACS and IBIS/PICsIT
in coincidence with GRB150101B (GCN 17267, GCN 17276). Troja et al.
(2018, arXiv:1806.10624) suggest that GRB150101B is a kilonova event
comparable to GW170817/GRB170817A, but at cosmological distance and
without the observations of a gravitational-wave trigger. The INTEGRAL
orientation was 24.9 degrees from the GRB location and implies a
somewhat suppressed response for SPI-ACS, but an improved response for
IBIS, especially IBIS/PICsIT (Savchenko et al. 2017, A&A 603, A46).

We confirm the independent detection by SPI-ACS and IBIS/PICsIT of a
short duration (~0.012 sec) event, consistent with that reported in
Troja et al. The signal in SPI-ACS (75 keV-10 MeV) and in IBIS/PICsIT
(200 keV-1.2 MeV) has a S/N of 5.1, and 4.2, respectively.

 From the SPI-ACS observation, we estimate a 75 keV-2 MeV fluence of
GRB150101B in the time interval T_0-0.05s - T_0+0.1s of (1.3 Â±
0.3)e-7 erg/cm2, assuming a simple power-law spectrum with a slope of
1.2 (as measured by Swift/BAT and Fermi/GBM).

Analysis is on-going to constrain any possible soft gamma-ray
afterglow with contemporaneous INTEGRAL observations.

A plot of the light curve can be found at
https://zenodo.org/record/1304812#.WzyLLa14VGw


GRB_name: GRB180704A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22890
SUBJECT: GRB 180704A: Enhanced Swift-XRT position
DATE:    18/07/04 10:31:38 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 4046 s of XRT Photon Counting mode data and 7 UVOT
images for GRB 180704A, 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 = 32.66048, +69.96408 which is equivalent
to:

RA (J2000): 02h 10m 38.51s
Dec (J2000): +69d 57' 50.7"

with an uncertainty of 1.5 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: GRB180703A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22891
SUBJECT: GRB 180703A: Swift-XRT observations
DATE:    18/07/04 12:02:52 GMT
FROM:    Antonino D'Ai at IASF-PA  <antonino.dai@ifc.inaf.it>

S.L. Gibson (U. Leicester), Z. Liu (NAOC / U. Leicester), P. D'Avanzo
(INAF-OAB), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), S. J. LaPorte
(PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), J.P. Osborne
(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
Fermi/LAT-detected burst GRB 180703A (Racusin et al. GCN Circ. 22883)
in a series of observations tiled on the sky. The total exposure time
is 2.0 ks, distributed over 4 tiles; the maximum exposure at a single
sky location was 863 s. The data were collected between T0+16.9 ks and
T0+29.0 ks, and are entirely in Photon Counting (PC) mode. 

One uncatalogued X-ray source has been detected, it is below the RASS
limit and shows no definitive signs of fading. Therefore, at the
present time we cannot confirm this as the afterglow. Details of this
source are given below:

Source 1:
  RA (J2000):  6.4693  =  00:25:52.63
  Dec (J2000): -67.1802  =  -67:10:48.7
  Error: 5.5 arcsec (radius, 90% conf.)
  Count-rate: 0.0207 [+0.0067, -0.0055] ct s^-1   
  Distance: 339 arcsec from Fermi/LAT position.
  Flux: (1.22 [+0.39, -0.32])e-12 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 tiled XRT
observations, including a position-specific upper limit calculator, are
available at http://www.swift.ac.uk/xrt_products/TILED_GRB00070.

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


GRB_name: GRB180703A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22892
SUBJECT: GRB 180703A: LCO Sutherland possible optical candidate
DATE:    18/07/04 13:26:02 GMT
FROM:    Renato Martone at Universita' di Ferrara  <mrtrnt@unife.it>

C. Guidorzi, R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell (U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU), A. Cucchiara, D. Morris (U. of Virgin Islands) on behalf of a large collaboration report:

One of the LCO 1-m units at Sutherland Observatory (South Africa) began observing Fermi-LAT GRB 180703A (Racusin et al. GCN 22883) on July 04, 02:34 UT (5.5 hours after the GRB trigger time) with the SDSS i' filter. On the border of the Swift-XRT error circle of source S1 (Gibson et al. GCN 22891) we marginally detect an object at the following position:

RA(J2000)=  00:25:52.35
DEC(J2000)= -67:10:43.4

with an error radius of ~1" and a magnitude of i'=20.6 +- 0.3 at a mid time of 5.65 hours post GRB, as calibrated against nearby USNOB-UCAC4 stars.


GRB_name: GRB180704A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22893
SUBJECT: GRB 180704A: Swift/UVOT Upper Limits
DATE:    18/07/04 13:31:43 GMT
FROM:    Sam Emery at MSSL-UCL  <samuel.emery.15@ucl.ac.uk>

S.W.K. Emery (UCL-MSSL) and E. Sonbas (Adiyaman Univ.) and
A. A. Breeveld (UCL-MSSL)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180704A
3255 s after the BAT trigger (Sonbas et al., GCN Circ. 22885).
No optical afterglow consistent with the XRT position
(Evans et al. GCN Circ. 22890)
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
exposures are:

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

white             3255         5455          537         >20.8
v                 4233        10567         1082         >19.8
b                 3618         5253          393         >19.9
u                 3413         5048          393         >19.6
uvw1                4643         4843          197         >19.2
uvm2                4438        11190          804         >20.3
uvw2                4028         9654         1082         >20.7

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.87 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB180704A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22894
SUBJECT: GRB 180704A: Swift-BAT refined analysis
DATE:    18/07/04 13:36:38 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC), J. R. Cummings (CPI),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL),
T. Sakamoto (AGU), E. Sonbas (Adiyaman Univ.), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
 
Using the data set from T-239 to T+760 sec from recent telemetry downlinks,
we report further analysis of BAT GRB 180704A (trigger #846088)
Sonbas, et al., GCN Circ. 22885).  The BAT ground-calculated position is
RA, Dec = 32.605, 69.965 deg, which is 
   RA(J2000)  =  02h 10m 25.1s 
   Dec(J2000) = +69d 57' 54.9" 
with an uncertainty of 1.3 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 7%.
 
The mask-weighted light curve shows several peaks, the first starting at ~T-21 sec,
and the lagest peak at ~T+1 sec, with a long tail out to ~T+40 sec.
T90 (15-350 keV) is 19.7 +- 1.4 sec (estimated error including systematics).
 
The time-averaged spectrum from T-17.90 to T+4.24 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.22 +- 0.10.  The fluence in the 15-150 keV band is 6.2 +- 0.4 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+0.04 sec in the 15-150 keV band
is 9.6 +- 1.2 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/846088/BA/


GRB_name: GRB180704A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22895
SUBJECT: GRB 180704A: Swift-XRT refined Analysis
DATE:    18/07/04 14:21:37 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

Z. Liu (NAOC / U. Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA),
A. Melandri (INAF-OAB), J.A. Kennea (PSU), B. Sbarufatti
(INAF-OAB/PSU), D.N. Burrows (PSU), J.P. Osborne (U. Leicester), K.L.
Page (U. Leicester) and E. Sonbas report on behalf of the Swift-XRT
team:

We have analysed 7.9 ks of XRT data for GRB 180704A (Sonbas et al. GCN
Circ. 22885), from 3.2 ks to 22.5 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. 22890).

The light curve can be modelled with an initial power-law decay with an
index of alpha=0.91 (+/-0.12), followed by a break at T+13.2 ks to an
alpha of 2.5 (+0.7, -0.6).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.92 (+0.14, -0.13). The
best-fitting absorption column is  8.3 (+1.2, -1.1) x 10^21 cm^-2, in
excess of the Galactic value of 4.9 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 4.8 x 10^-11 (8.2 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      8.3 (+1.2, -1.1) x 10^21 cm^-2
Galactic foreground: 4.9 x 10^21 cm^-2
Excess significance: 4.9 sigma
Photon index:      1.92 (+0.14, -0.13)

If the light curve continues to decay with a power-law decay index of
2.5, the count rate at T+24 hours will be 2.1 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.0 x
10^-13 (1.8 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/00846088.

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


GRB_name: GRB180703A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22896
SUBJECT: GRB 180703A: Fermi GBM detection
DATE:    18/07/04 16:59:58 GMT
FROM:    Suraj Poolakkil at UAH  <sp0076@uah.edu>

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

"At 21:01:40.50 UT on 03 July 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180703A (trigger 552344505 / 180703876),
which was also detected by the Fermi LAT (Racusin et al. 2018, GCN 22883).
The GBM on-ground location is consistent with the LAT position.

The angle from the Fermi LAT boresight
at the GBM trigger time is 44 degrees.

The GBM light curve shows a single peak
with a duration (T90) of about 20.2 s (50-300 keV).
The time-averaged spectrum from T0-3.1 s to T0+25.6 s is
best fit by a Band function with Epeak = 360 +/- 33 keV,
alpha = -0.80 +/- 0.04 and beta = -1.95 +/- 0.08.

The event fluence (10-1000 keV) in this time interval is
(2.001 +/- 0.043)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+3.52 s in the 10-1000 keV band
is 11.1 +/- 0.25 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB180703B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22897
SUBJECT: GRB 180703B: Fermi GBM detection
DATE:    18/07/04 17:00:32 GMT
FROM:    Suraj Poolakkil at UAH  <sp0076@uah.edu>

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

"At 22:46:51.32 UT on 03 July 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180703B (trigger 552350816/ 180703949),
which was also detected by the Fermi LAT (Racusin et al. 2018, GCN 22884).
The GBM on-ground location is consistent with the LAT position.

The angle from the Fermi LAT boresight
at the GBM trigger time is 31 degrees.

The GBM light curve shows two peaks
with a duration (T90) of about 1.6 s (50-300 keV).
The time-averaged spectrum from T0-0.1 s to T0+2.4 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.79 +/- 0.03 and
the cutoff energy, parameterized as Epeak, is 138 +/- 3 keV.

The event fluence (10-1000 keV) in this time interval is
(8.281 +/- 0.119)E-06 erg/cm^2. The 64-ms peak photon flux measured
starting from T0+1.21 s in the 10-1000 keV band
is 103.9 +/- 2.92 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB180703A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22898
SUBJECT: GRB 180703A: Swift/UVOT Upper Limits
DATE:    18/07/04 17:04:13 GMT
FROM:    Sam Emery at MSSL-UCL  <samuel.emery.15@ucl.ac.uk>

S.W.K. Emery (UCL-MSSL) and E. Sonbas (Adiyaman Univ.)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180703A
17269 s after the Fermi/LAT trigger (Racusin et al. GCN Circ. 22883).
No optical afterglow consistent with the XRT position of the
uncatalogued X-ray source, source 1 (Gibson et al. GCN Circ. 22891)
or the position from LCO Sutherland (Guidorzi et al. GCN Circ. 22892)
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
exposures at the position of source 1 are:

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

b             17353         28862           47         >19.2
u             17323         28834          116         >19.5
uvw1          17269         28807          234         >19.8
uvw2          17384         28917           97         >19.2

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB180704B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22899
SUBJECT: GRB 180704B: CALET Gamma-Ray Burst Monitor detection
DATE:    18/07/05 12:07:02 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

Y. Asaoka (Waseda U), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita,
Y. Kawakubo, A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito,
H. Morita, Y. Sone (AGU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
I. Takahashi (IPMU), S. Ozawa, S. Torii (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), W. Ishizaki (ICRR), M. L. Cherry (LSU),
S. Ricciarini (U of Florence), A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long GRB 180704B (INTEGRAL SPI-ACS trigger 8095; Konus-Wind
trigger time on 12:36:28.83) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 12:36:29.282 UTC on 4 July 2018.
The burst signal was seen by all CGBM detectors.

The burst light curve shows a weak precursor which starts
at T-39.5 sec and ends at T-28.2 sec followed by the main pulse
which starts at T+0.8 sec, peaks at T+8.6 sec, and ends at T+31.5 sec.
The T90 and the T50 durations measured by the SGM data are
56.5 +- 5.6 sec and 7.6 +- 0.9 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1214742901/

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


GRB_name: GRB180703A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22900
SUBJECT: GRB 180703A: AstroSat CZTI detection
DATE:    18/07/05 13:40:47 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

V. Sharma, A. Vibhute and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:

Analysis of Astrosat CZTI data showed the detection of a long GRB 180703A, which was also detected by Swift (Evans P. A. et al., GCN 22882), Fermi-LAT (Racusin J. L. et al., GCN 22883), Swift-XRT (Gibson S. L. et al., GCN 22891) and Fermi-GBM (Poolakkil S. et al., GCN 22896).

The source was clearly detected in the 40-200 keV energy range. The light curve shows a single peak of emission with peak at 21:01:44.5 UT, ~4 s after the GBM trigger. The measured peak count rate is 277.3 cts/s above the background in combined data of four quadrants, with a total of 2182 cts. The local mean background count rate was 519.6 cts/s. Using cumulative rates, we measure a T90 of 20.9 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: GRB180704A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22901
SUBJECT: GRB 180704A: AstroSat CZTI detection
DATE:    18/07/05 13:41:47 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

V. Sharma, A. Vibhute and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:

Analysis of Astrosat CZTI data showed the detection of a long GRB 180704A, which was also detected by Swift-BAT (Sonbas E. et al., GCN 22885) and Swift-XRT (Burrows D. N. et al., GCN 22887).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 05:36:43.500 UT. The measured peak count rate is 660.2 cts/s above the background in combined data of four quadrants, with a total of 5324 cts. The local mean background count rate was 571.8 cts/s. Using cumulative rates, we measure a T90 of 26 s. In preliminary analysis, we find that 463 compton events are associated with this event.

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: GRB180705A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22902
SUBJECT: GRB 180705A: Swift detection of a burst
DATE:    18/07/05 15:55:08 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

M. Stamatikos (OSU/NASA/GSFC), S. D. Barthelmy (GSFC),
A. A. Breeveld (UCL-MSSL), A. D'Ai (INAF-IASFPA), V. D'Elia (ASDC),
A. Deich (PSU), S. W. K Emery (UCL-MSSL), J.D. Gropp (PSU),
J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL), B. Sbarufatti (PSU)
and M. H. Siegel (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 15:41:14 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180705A (trigger=846299).  Swift did not slew due to an observing
constraint.  The BAT on-board calculated location is 
RA, Dec 212.594, -11.630, which is 
   RA(J2000)  =  14h 10m 23s
   Dec(J2000) = -11d 37' 48"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  As is typical for image triggers, the real-time light
curve does not show anything significant. The image trigger significance is 7.8
sigma, therefore we have high confidence in this event. 

Due to an observing constraint, Swift will not slew until T0+54
minutes. There will be no XRT or UVOT data until this time. 

Burst Advocate for this burst is M. Stamatikos (Michael.Stamatikos-1 AT nasa.gov). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB180705A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22903
SUBJECT: GRB 180705A: Swift-XRT observations
DATE:    18/07/05 17:10:37 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

J.A. Kennea (PSU), G. Tagliaferri (INAF-OAB), S. Campana (INAF-OAB),
P.A. Evans (U. Leicester), J.P. Osborne (U. Leicester) and D.N. Burrows
(PSU) report on behalf of the Swift-XRT team:

The XRT began observing the field of GRB 180705A at 16:37:18.4 UT,
3363.7 seconds after the BAT trigger. Using promptly downlinked data we
find an uncatalogued X-ray source located at RA, Dec 212.61326,
-11.64841 which is equivalent to:
   RA(J2000)  = 14h 10m 27.18s
   Dec(J2000) = -11d 38' 54.3"
with an uncertainty of 4.3 arcseconds (radius, 90% containment). This
location is 94 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 http://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.


GRB_name: GRB180705A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22904
SUBJECT: GRB 180705A: MASTER optical observation
DATE:    18/07/05 18:08:43 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, V.Kornilov,  N.Tiurina, A.Kuznetsov, V.Chazov,
I. Gorbunov, D. Vlasenko, D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov
Lomonosov Moscow State University,SAI

D. Buckley,
South African Astronomical Observatory (SAAO)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias (IAC)

A. Tlatov, V.Senik, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

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

H.Levato,
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University (ISU)

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


MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) ,
located in South African Astronomical Observatory,
was pointed to the Swift GRB180705A (BAT: Stamatikos et al. GCN 22902, GRBtime: 2018-07-05 15:41:14UT; XRT : RA,Dec2000=14h 10m 27.18s -11d 38' 54.3"  Kennea et al. GCN22903)
at 2018-07-05 15:54:52  ( GRB  Altitude: 55.90, Sun: Altitude: -3.10) at sunset.

So MASTER-SAAO started GRB180705A observations at 2018-07-05 16:35:54UT (GRB altitute: 62.78, Sun: Altitude: -11.10).

MASTER automatic unfiltered (W=0.2B+0.8R by USNO-B1) limits are the following

T_start,UT             Exp,s    mlim   MASTER-II
2018-07-05 16:35:54 540 18.8 WEST
2018-07-05 16:35:54 180 17.9 WEST
2018-07-05 16:35:59 540 18.3 EAST
2018-07-05 16:35:59 180 17.5 EAST
2018-07-05 16:39:32 180 18.2 WEST
2018-07-05 16:39:37 180 17.9 EAST
2018-07-05 16:44:51 180 18.7 WEST
2018-07-05 16:44:56 180 18.4 EAST
2018-07-05 16:48:21 540 19.7 WEST
2018-07-05 16:48:21 180 18.8 WEST
2018-07-05 16:48:25 540 19.5 EAST
2018-07-05 16:48:25 180 18.5 EAST
2018-07-05 16:51:52 180 19.0 WEST
2018-07-05 16:51:56 180 18.8 EAST
2018-07-05 16:55:26 180 19.0 WEST
2018-07-05 16:55:30 180 18.8 EAST
2018-07-05 16:58:59 540 19.9 WEST
2018-07-05 16:58:59 180 19.3 WEST
2018-07-05 16:59:04 540 19.7 EAST
2018-07-05 16:59:04 180 19.0 EAST
2018-07-05 17:02:29 180 19.3 WEST
2018-07-05 17:02:34 180 19.0 EAST
2018-07-05 17:05:58 180 19.3 WEST
2018-07-05 17:06:03 180 19.0 EAST
2018-07-05 17:09:33 540 20.0 WEST
2018-07-05 17:09:33 180 19.3 WEST
2018-07-05 17:09:37 540 19.6 EAST
2018-07-05 17:09:37 180 19.0 EAST
2018-07-05 17:13:06 180 19.3 WEST
2018-07-05 17:13:10 180 19.1 EAST
2018-07-05 17:16:51 180 19.3 WEST
2018-07-05 17:16:56 180 19.0 EAST
2018-07-05 17:20:25 180 19.3 WEST
2018-07-05 17:20:29 180 19.0 EAST

The message may be cited.


GRB_name: GRB180705A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22906
SUBJECT: GRB 180705A: Enhanced Swift-XRT position
DATE:    18/07/05 19:08:58 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 1348 s of XRT Photon Counting mode data and 4 UVOT
images for GRB 180705A, 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 = 212.61323, -11.64745 which is equivalent
to:

RA (J2000): 14h 10m 27.17s
Dec (J2000): -11d 38' 50.8"

with an uncertainty of 1.8 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: GRB180705A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22907
SUBJECT: GRB 180705A: Swift-BAT refined analysis
DATE:    18/07/06 03:32:53 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (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 180705A (trigger #846299)
(Stamatikos et al., GCN Circ. 22902).  The BAT ground-calculated position is
RA, Dec = 212.605, -11.640 deg which is
  RA(J2000)  =  14h 10m 25.1s
  Dec(J2000) = -11d 38' 23.7"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 36%.

The mask-weighted light curve shows some weak emission that starts at ~T0 and
ends at ~T+130 s. However, the burst went out of the BAT FOV from T+158 s to
T+204 s due to a preplanned slew, and thus there might be additional
emission when the burst was out of the FOV. The burst came back in the BAT FOV
shortly during the slew period (from T0+205 s to T0+262 s), though no emission
are found during this time. T90 (15-350 keV) is 123.2 +- 16.6 sec (estimated
error including systematics).

The time-averaged spectrum from T+0.26 to T+133.70 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.63 +- 0.22.  The fluence in the 15-150 keV band is 2.0 +- 0.3 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+3.60 sec in the 15-150 keV band
is 0.7 +- 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/846299/BA/


GRB_name: GRB180703B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22908
SUBJECT: IPN Triangulation of GRB 180703B
DATE:    18/07/06 05:14:31 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

K. Hurley, on behalf of the IPN,

I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, D. Svinkin,
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,

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

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

and

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

The short duration GRB 180703B
(Fermi-LAT detection: Racusin et al., GCN Circ. 22884;
CGBM detection: Takahasi et al., GCN Circ. 22888;
Fermi-GBM detection: Poolakkil and Meegan, GCN Circ. 22897)
was detected by Fermi (GBM trigger 552350816), Konus-Wind,
INTEGRAL (SPI-ACS), Mars-Odyssey (HEND), CALET (CGBM),
and Swift (BAT), at about 82009 s UT (22:46:49).
The burst was outside the coded field of view of the BAT.

We have triangulated it to a Konus-HEND annulus centered at
RA(2000)=132.436 deg (08h 49m 45s)  Dec(2000)=+22.998 deg (+22d 59' 54"),
whose radius is 62.605 +/- 0.326 deg (3 sigma).

The LAT position reported by Racusin et al. (GCN Circ. 22884)
is consistent with the annulus. The annulus combined with
the LAT (90 % containment, statistical-only) error circle
gives the following error box:
---------------------------------------------
  RA(2000), deg  Dec(2000), deg
---------------------------------------------
Center:
     97.0594 -29.7187
Corners:
     96.9223 -29.8774
     97.2925 -30.1165
     97.1962 -29.5599
     96.5548 -29.6361
---------------------------------------------
The error box area is 894.7 sq. arcmin
(a factor of 2 smaller than that of the LAT error circle).

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB180703_T82008/IPN


GRB_name: GRB180706A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22909
SUBJECT: GRB 180706A: Swift detection of a burst with optical counterpart
DATE:    18/07/06 08:43:15 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

M. Stamatikos (OSU/NASA/GSFC), S. D. Barthelmy (GSFC),
A. P. Beardmore (U Leicester), A. D'Ai (INAF-IASFPA),
V. D'Elia (ASDC), P. A. Evans (U Leicester), J.D. Gropp (PSU),
J. A. Kennea (PSU) and K. L. Page (U Leicester) report on behalf of
the Neil Gehrels Swift Observatory Team:

At 08:24:40 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180706A (trigger=846395).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 181.665, +66.035, which is 
   RA(J2000)  =  12h 06m 40s
   Dec(J2000) = +66d 02' 05"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve shows two main peaks
with a total duration of about 40 sec.  The peak count rate
was ~4000 counts/sec (15-350 keV), at ~28 sec after the trigger. 

The XRT began observing the field at 08:26:08.0 UT, 87.7 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
uncatalogued X-ray source with an enhanced position: RA, Dec 181.6428,
66.0366 which is equivalent to:
   RA(J2000)  = 12h 06m 34.28s
   Dec(J2000) = +66d 02' 11.6"
with an uncertainty of 2.4 arcseconds (radius, 90% containment). This
location is 32 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 http://www.swift.ac.uk/sper.  We
cannot determine whether the source is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 1.44
x 10^20 cm^-2 (Willingale et al. 2013). 

The initial flux in the 2.5 s image was 7.91e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 250 seconds with the U filter starting
307 seconds after the BAT trigger. There is a candidate afterglow in the
rapidly available 2.7'x2.7' sub-image at
  RA(J2000)  = 12:06:34.34 = 181.64308
  DEC(J2000) = +66:02:13.6  =  66.03712
with a 90%-confidence error radius of about 0.77 arc sec. This position is 2.9
arc sec. from the center of the XRT error circle. The estimated magnitude is
17.74 with a 1-sigma error of about  0.15. No correction has been made for the
expected extinction corresponding to E(B-V) of 0.02. 

Burst Advocate for this burst is M. Stamatikos (Michael.Stamatikos-1 AT nasa.gov). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB180706A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22910
SUBJECT: GRB 180706A: COATLI Optical Detection 
DATE:    18/07/06 09:02:57 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), Carlos
RomÃ¡n-ZÃºÃ±iga (UNAM), and William H. Lee (UNAM) report:

We observed the field of the GRB 180706A (Stamatikos et al., GCN Circ.
22909) with the COATLI 50-cm telescope and interim imager (Watson et al.
2016, Proc. SPIE, 9908, 50) at the Observatorio AstronÃ³mico Nacional on
the Sierra de San Pedro MÃ¡rtir from 2018-07-06 08:25:26.83 (29.5 seconds
after alert and 46.4 seconds after trigger) to 08:50:34, obtaining 795
seconds of exposure in the w filter.

We detect an uncatalogued source in the XRT error region with a
preliminary magnitude of

  w = 18.73 +/- 0.08

This magnitude is calibrated against the USNO-B1 catalog (adjusted to an
approximate AB system) and is not corrected for Galactic extinction in
the direction of the GRB.

At the moment we have no information on fading. Further observations are
planned.

We thank the COATLI technical team (Fernando Ãngeles, Oscar Chapa,
Salvador Cuevas, Alejandro Farah, Jorge Fuentes, RosalÃ­a Langarica,
Fernando QuirÃ³s, and Carlos Tejada) and the staff of the Observatorio
AstronÃ³mico Nacional.


GRB_name: GRB180705A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22911
SUBJECT: GRB 180705A: RATIR Optical Observations 
DATE:    18/07/06 09:19:42 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Alexander Kutyrev (GSFC),
William H. Lee (UNAM), Michael G. Richer (UNAM), Ori Fox (STScI), J.
Xavier Prochaska (UCSC), Josh Bloom (UCB), Antonino Cucchiara (UVI),
Eleonora Troja (GSFC), Owen Littlejohns (ASU), Enrico Ramirez-Ruiz
(UCSC), JesÃºs GonzÃ¡lez (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Harvey
Moseley (GSFC), John Capone (UMD), V. Zach Golkhou (U. Wash.), and Vicki
Toy (UMD) report:

We observed the field of GRB 180705A (Stamatikos et al., GCN Circ.
22902) with the Reionization and Transients Infrared Camera (RATIR;
www.ratir.org) on the 1.5m Harold Johnson Telescope at the Observatorio
AstronÃ³mico Nacional on Sierra San Pedro MÃ¡rtir from 2018/07 6.16 to
2018/07 6.27 UTC (12.19 to 14.82 hours after the BAT trigger), obtaining
a total of 1.74 hours exposure in the r and i bands.

For a source within the Swift-XRT error circle (Kennea et al., GCN Circ.
22903), in comparison with the SDSS DR9 catalog, we obtain the following
3-sigma upper limits:

  r > 23.20 
  i > 23.07

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

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


GRB_name: GRB180705A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22912
SUBJECT: GRB 180705A: Swift/UVOT Upper Limits
DATE:    18/07/06 10:11:35 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>

A. A. Breeveld (UCL-MSSL), S. W. K Emery (UCL-MSSL) and M. Stamatikos 
(OSU/NASA/GSFC) report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180705A
3368 s after the BAT trigger (Stamatikos et al., GCN Circ. 22902).
No optical afterglow consistent with the enhanced XRT position (Goad et 
al. GCN Circ. 22906) 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          3368         3485          115         >20.2
white             3368         5327          312         >20.8
v                 4103         5738          393         >18.9
b                 4923        11649          311         >20.5
u                 4718        11527         1082         >21.0
w1                4513        16889          483         >20.5
m2                4308        15205          647         >20.1
w2                5333         5533          197         >20.4

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 0.06 in the direction of the 
burst (Schlegel et al. 1998).


GRB_name: GRB180705A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22913
SUBJECT: GRB 180705A: TSHAO optical upper limit
DATE:    18/07/06 11:29:42 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

E. Mazaeva (IKI), A. Pozanenko (IKI),  A. Kusakin (FAPHI), I. Reva 
(FAPHI),  A. Volnova (IKI), M. Krugov (FAPHI) report on behalf of larger 
GRB follow-up collaboration:

We observed the field of GRB 180705A  (Stamatikos et al., GCN 22902) 
with Zeiss-1000 1-m telescope of Tien Shan Astronomical Observatory 
starting on July 05 (UT) 16:13:52. We obtained several images in 
R-filter.  Within enhanced XRT Swift-XRT position (Goad et al., GCN 
22906)  we do not detect any object.  Preliminary photometry of the 
field is following.

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

2018-07-05  16:13:52 0.04895  R      25*120  n/d  n/d    21.3

The photometry is based on several nearby SDSS-DR12 stars.

Ref.stars
SDSS-DR12_id           R(Lupton)
J141030.67-113927.0    17.460
J141015.17-113809.7    17.680


GRB_name: GRB180703B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22914
SUBJECT: Konus-Wind observation of GRB 180703B
DATE:    18/07/06 11:56:57 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

D. Frederiks, S. Golenetskii, R.Aptekar, A. Kozlova,
A.Lysenko,  D. Svinkin, A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

GRB 180703B (IPN Triangulation: Hurley et al., GCN 22908;
Fermi-LAT detection: Racusin et al., GCN 22884;
Fermi-GBM detection: Poolakkil & Meegan, GCN 22897)
triggered Konus-Wind at T0=82008.633 s UT (22:46:48.633)

The burst light curve shows two prominent peaks,
with a total duration of ~2.0 s.
The emission in the main peak is seen up to ~2 MeV.

As observed by Konus-Wind, the burst had a fluence of
(6.4 Â± 0.4)x10^-6 erg/cm2 and a 64-ms peak energy flux,
measured from T0+1.088, of (1.60 Â± 0.09)x10^-5 erg/cm2
(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 - 2 MeV range by a cutoff power-law
(CPL) function with the following model parameters:
the photon index alpha = -0.74(-0.18,+0.19),
and the peak energy Ep = 131(-9,+11) keV,
chi2 = 55/57 dof.
Fitting this spectrum with the GRB (Band) function yields
the same alpha and Ep, and only an upper limit on beta (<-3.3).


The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB180703_T82008/

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


GRB_name: GRB180701A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22915
SUBJECT: Konus-Wind observation of GRB 180701A
DATE:    18/07/06 12:18:26 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

A. Kozlova, S. Golenetskii, R.Aptekar, D. Frederiks,
M. Ulanov, D. Svinkin, A. Tsvetkova, A.Lysenko,
and T. Cline on behalf of the Konus-Wind team, report:

A long GRB was detected by Konus-Wind (KW) in the
waiting mode on July 1, 2018 at ~23864 s UT (06:37:44),
~600 s before the MAXI trigger (GRB 180701A;
Maruyama et al., GCN 22880).

The burst light curve shows a single pulse
with a duration of ~ 12 s. Taking into account the
proximity of this burst to the MAXI/GSC trigger and
the consistency of the KW ecliptic latitude response with
the position of GRB 180701A we suggest that KW observed
the main part of GRB 180701A.

As observed by KW, the burst had a fluence of
1.85(-0.13,+0.64)x10^-6 erg/cm2 and a 2.944-s peak flux,
measured from ~T0(MAXI)-555.6 s, of 2.47(-0.75,+1.13)x10^-7 erg/cm2/s
(both in the 20 keV - 10 MeV energy range).

Modeling the KW 3-channel time-integrated spectrum
(from ~T0(MAXI)-558.6 s to ~T0(MAXI)-546.8 s)
by a simple power-law model yields the power law
index of -2.52(-0.11,+0.25), chi2 = 1.3/1 dof.

The KW light curve of this burst is available at
http://www.ioffe.rssi.ru/LEA/GRBs/GRB180701A

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


GRB_name: GRB180706A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22916
SUBJECT: GRB 180706A: Enhanced Swift-XRT position
DATE:    18/07/06 14:46:59 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 1356 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 180706A, 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 = 181.64259, +66.03714 which is equivalent
to:

RA (J2000): 12h 06m 34.22s
Dec (J2000): +66d 02' 13.7"

with an uncertainty of 1.7 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: GRB180706A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22917
SUBJECT: GRB 180706A: Swift-XRT refined Analysis
DATE:    18/07/06 15:38:54 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB),
B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), A. Tohuvavohu (PSU),
J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore
(U. Leicester) and M. Stamatikos report on behalf of the Swift-XRT
team:

We have analysed 6.1 ks of XRT data for GRB 180706A (Stamatikos et al.
GCN Circ. 22909), from 77 s to 17.9 ks after the  BAT trigger. The data
comprise 169 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 Osborne et
al. (GCN Circ. 22916).

The late-time light curve (from T0+5.5 ks) can be modelled with a
power-law decay with a decay index of alpha=0.58 (+0.21, -0.22).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 3.11 (+/-0.09). The
best-fitting absorption column is  1.65 (+/-0.18) x 10^21 cm^-2, in
excess of the Galactic value of 1.4 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 2.16 (+0.17, -0.16)
and a best-fitting absorption column of 6.7 (+3.7, -3.3) x 10^20 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 3.0 x 10^-11 (3.6 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      6.7 (+3.7, -3.3) x 10^20 cm^-2
Galactic foreground: 1.4 x 10^20 cm^-2
Excess significance: 2.6 sigma
Photon index:      2.16 (+0.17, -0.16)

If the light curve continues to decay with a power-law decay index of
0.58, the count rate at T+24 hours will be 0.026 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 7.7 x
10^-13 (9.3 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/00846395.

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


GRB_name: GRB180704A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22918
SUBJECT: Konus-Wind observation of GRB 180704A
DATE:    18/07/06 16:06:15 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

D. Frederiks, S. Golenetskii, R.Aptekar, A. Kozlova,
A.Lysenko,  D. Svinkin, A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The long GRB 180704A (Swift/BAT detection: Sonbas et al.,
GCN 22885; Markwardt et al., GCN 22894;
AstroSat CZTI detection: Sharma et al., GCN 22901)
triggered Konus-Wind at T0=20182.254 s UT (05:36:22.254).

The KW light curve shows a multi-peaked structure with
a total duration of ~40 s. A possible precursor is
seen in the waiting mode data around T0 - 62 s.
The emission is seen up to ~4 MeV.

As observed by Konus-Wind, the burst had a fluence of
(1.8 Â± 0.1)x10^-5 erg/cm2 and a 64-ms peak energy flux,
measured from T0+20.352, of (2.4 Â± 0.2)x10^-6 erg/cm2
(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 cutoff power-law
(CPL) function with the following model parameters:
the photon index alpha = -0.49(-0.13,+0.14),
and the peak energy Ep = 183(-11,+33) keV,
chi2 = 98/98 dof.
Fitting this spectrum with the GRB (Band) function yields
the same alpha and Ep, and only an upper limit on beta (<-3.2).

The spectrum near the peak count rate (measured from T0+16.640
to T0+24.832 s) is best fit in the 20 keV - 15 MeV range by
the CPL function with the following model parameters:
the photon index alpha = -0.38(-0.20,+0.22),
and the peak energy Ep = 163(-13,+15) keV,
chi2 = 121/98 dof.
Fitting this spectrum with the GRB (Band) function yields
the same alpha and Ep, and only an upper limit on beta (<-3.2).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB180704_T20182/

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


GRB_name: GRB180706A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22919
SUBJECT: GRB 180706A: Fermi GBM observation
DATE:    18/07/06 17:06:31 GMT
FROM:    Elisabetta Bissaldi at INFN,Bari  <elisabetta.bissaldi@ba.infn.it>

E. Bissaldi (Politecnico & INFN Bari)
reports on behalf of the Fermi GBM Team:


"At 08:25:09.03 UT on 06 July 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180706A (trigger 552558314 / 180706351),
which was also detected by the Swift/BAT (Stamatikos et al. 2018, GCN 22909).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 60 degrees.

The GBM light curve consists of multiple peaks
with a duration (T90) of about 38 s (50-300 keV).
The time-averaged spectrum from T0-30 s to T0+10 s is
adequately fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.98 +/- 0.13 and
the cutoff energy, parameterized as Epeak, is 53 +/- 4 keV.

The event fluence (10-1000 keV) in this time interval is
(3.3 +/- 0.2)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0-2 s in the 10-1000 keV band is 4.9 +/- 0.3 ph/s/cm^2.


The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB180705A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22920
SUBJECT: GRB 180705A: Swift-XRT refined Analysis
DATE:    18/07/06 17:10:02 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), D.N. Burrows (PSU), A.
Tohuvavohu (PSU), S. J. LaPorte (PSU), K.L. Page (U. Leicester), A.P.
Beardmore (U. Leicester), P.A. Evans (U. Leicester), V. D'Elia (ASDC)
and M. Stamatikos report on behalf of the Swift-XRT team:

We have analysed 5.7 ks of XRT data for GRB 180705A (Stamatikos et al.
GCN Circ. 22902), from 3.4 ks to 56.6 ks after the  BAT trigger. The
data comprise 1.1 ks in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Goad et al. (GCN Circ. 22906).

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.12 (+0.17, -0.13).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.99 (+0.32, -0.30). The
best-fitting absorption column is  3.9 (+1.8, -1.5) x 10^21 cm^-2, in
excess of the Galactic value of 5.8 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.9 x 10^-11 (6.0 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      3.9 (+1.8, -1.5) x 10^21 cm^-2
Galactic foreground: 5.8 x 10^20 cm^-2
Excess significance: 3.7 sigma
Photon index:      1.99 (+0.32, -0.30)

If the light curve continues to decay with a power-law decay index of
1.12, the count rate at T+24 hours will be 6.4 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.5 x
10^-13 (3.8 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/00846299.

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


GRB_name: GRB180706A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22921
SUBJECT: GRB 180706A: Swift-BAT refined analysis
DATE:    18/07/06 18:11:57 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

T. Sakamoto (AGU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (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 180706A (trigger #846395)
(Stamatikos et al., GCN Circ. 22909).  The BAT ground-calculated position is
RA, Dec = 181.687, 66.044 deg which is
  RA(J2000)  =  12h 06m 45.0s
  Dec(J2000) = +66d 02' 40.1"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 86%.

The mask-weighted light curve shows a double-peaked structure that starts
at ~T-20 s and ends at ~T+50 s. The smaller peak occurs at ~T+2 s, and
the larger peak happens at ~T+28 s. T90 (15-350 keV) is 42.7 +- 8.7 sec
(estimated error including systematics).

The time-averaged spectrum from T-18.77 to T+50.99 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.90 +- 0.08.  The fluence in the 15-150 keV band is 2.4 +- 0.1 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+27.82 sec in the 15-150 keV band
is 3.2 +- 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/846395/BA/


GRB_name: GRB180706A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22922
SUBJECT: GRB 180706A: Swift/UVOT Detection
DATE:    18/07/06 18:42:37 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

S. R. Oates (U.Warwick) and M. Stamatikos (OSU/NASA/GSFC)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180706A
95 s after the BAT trigger (Stamatikos et al., GCN Circ. 22909).
A source consistent with the XRT position
(Osborne et al. GCN Circ. 22916) and the COATLI optical detection 
(Watson et al. GCN Circ. 22910) is detected in the initial UVOT exposures.

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)          95          245          147         19.88 +/- 0.34
white              587          607           20         18.11 +/- 0.21
v                  637         1582          117         >18.5
b                  563          756           39         18.34 +/- 0.30
u                  308          557          246         17.90 +/- 0.12
w1                 686         1459           78         18.44 +/- 0.33
m2                 661         1606          117         >18.8
w2                 613         1558          117         >19.1

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB180706A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22923
SUBJECT: GRB 180706A: TSHAO optical observations
DATE:    18/07/06 21:15:30 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

A. Volnova (IKI), I. Reva (FAPHI), E. Mazaeva (IKI), A. Pozanenko (IKI), 
  A. Kusakin (FAPHI),  M. Krugov (FAPHI) report on behalf of larger GRB 
follow-up collaboration:

We observed the field of GRB 180706A  (Stamatikos et al., GCN 22909) 
with Zeiss-1000 telescope of Tien Shan Astronomical Observatory starting 
on July 06 (UT) 16:18:35. We obtained several images in R-filter.  The 
optical afterglow (Stamatikos et al., GCN 22909;  Watson et al., GCN 
22910)  is clearly detected in a combined image.  Preliminary photometry 
of the afterglow is following.

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

2018-07-06  16:18:35 0.35345  R      29*120  20.65 0.09   22.2

The photometry is based on several SDSS-DR12 stars.

Ref.stars
SDSS-DR12_id           R(Lupton)
J120642.39+660133.6 18.5600.025
J120649.22+660218.2 17.5190.018
J120653.24+660249.5 17.9870.017


GRB_name: GRB180706A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22924
SUBJECT: GRB 180706A: GOTO optical limits
DATE:    18/07/06 23:16:00 GMT
FROM:    Danny Steeghs at U.of Warwick/GOTO  <D.T.H.Steeghs@warwick.ac.uk>

K.Ulaczyk, D.Steeghs (U. Warwick), G.Ramsay (Armagh O.), M.Dyer
(U. Sheffield), B.Gompertz, J.Lyman, A.Levan, R.Cutter (U. Warwick)
K. Ackley, D.Galloway, E.Rol (Monash U.), V.Dhillon (U. Sheffield),
P.O'Brien, N.Tanvir (U. Leicester), S.Poshyachinda (NARIT),
D.Pollacco (U. Warwick), E.Thrane (Monash U.)

report on behalf of the GOTO collaboration:

In response to GRB 180706A (GCN 22909, 22910, 22916, 22917, 22919,
22921), the Gravitational-wave Optical Transient Observer (GOTO)
observed the field near the XRT position as reported by Osborne
et al. (GCN 22916).

Observations started at 2018-07-06T21:26:42 UT (13 hours after the
burst) and ended at 2018-07-06T23:49:54 and consisted of a set of
12x120s exposures in our wide L filter(400-700nm). We did not detect
a significant source corresponding to the reported optical counterpart.
A stacked image was used to derive a 5-sigma upper limit of V>21.6,
after astrometric and photometric (APASS V) calibrations.
This is consistent with the photometric evolution between the early
optical detections (GCN 22910, 22922) and the TSHAO magnitude reported
in Volnova et al. (GCN 22923).


GOTO is operated at the La Palma observing facilities of the University
of Warwick on behalf of a consortium including the University of
Warwick, Monash University, Armagh Observatory, the University of
Leicester, the University of Sheffield, the National Astronomical
Research Institute of Thailand (NARIT) and the Instituto de Astrofisica
de Canarias (IAC)

https://goto-observatory.org/


GRB_name: GRB180703A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22925
SUBJECT: IPN Triangulation of GRB 180703A
DATE:    18/07/07 08:32:45 GMT
FROM:    Anna Kozlova at Ioffe Institute  <ann_kozlova@mail.ioffe.ru>

K. Hurley, on behalf of the IPN,

I. G. Mitrofanov, D. Golovin, M. L. Litvak, and A. B. Sanin,
on behalf of the HEND-Odyssey GRB team,

A. Kozlova, S. Golenetskii, R. Aptekar, D. Frederiks, D. Svinkin,
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,

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

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

and

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

The long duration GRB 180703A
(Fermi-LAT detection: Racusin et al., GCN Circ. 22883;
Fermi-GBM detection: Poolakkil and Meegan, GCN Circ. 22896;
AstroSat CZTI detection: Sharma et al., GCN Circ. 22900)
was detected by Fermi (GBM trigger 552344505), Konus-Wind,
INTEGRAL (SPI-ACS), Mars-Odyssey (HEND), and Swift (BAT),
at about 75700 s UT (21:01:40). The burst was outside the
coded field of view of the BAT.

We have triangulated it to a Konus-HEND annulus centered at
RA(2000)=312.437 deg (20h 49m 45s)  Dec(2000)=-22.995 deg (-22d 59' 40"),
whose radius is 54.738 +/- 1.217 deg (3 sigma).

The annulus is consistent with, but does not reduce the area of, the LAT
position reported by Racusin et al. (GCN Circ. 22883).

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB180703_T75705/IPN


GRB_name: GRB180703A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22926
SUBJECT: GRB 180703A: MASTER optical observation 
DATE:    18/07/07 15:21:34 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, V.Kornilov,  N.Tiurina, A.Kuznetsov, V.Chazov,
I. Gorbunov, D. Vlasenko, D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov
Lomonosov Moscow State University,SAI

D. Buckley,
South African Astronomical Observatory (SAAO)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias (IAC)

A. Tlatov, V.Senik, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

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

H.Levato,
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University (ISU)

A. Gabovich, V. Yurkov, Yu. Sergienko
Blagoveschensk Educational State University (BSPU)
MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
South Africa (South African Astronomical Observatory) was pointed to the 
GRB180703A (Poolakkil et al., GCN Circ #22896) 17 sec after notice time 
and 576 sec after trigger time at 
2018-07-03 21:11:17 UT. On our first (120s exposure)  set we not  found
optical transient within FERMI error-box (ra=349.946 dec=-65.5794 r=1.62) 
brighter then 18.0.

MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
South Africa (South African Astronomical Observatory) was pointed to the 
GRB180703A (Racusin et al., GCN Circ #22883) 14961 sec after trigger time 
at  2018-07-04 01:11:02 UT . On our first (180s exposure)  set we  do not 
found  optical transients within LAT error-box (ra=6.54 dec=-67.09 
r=0.3)  brighter then 18.3.

The observations made on zenit distance = 44 degrees, galaxy latitude b = 
-50 degree.
The moon (72 % bright part) is 55 degrees above the horizon. The distance 
between  moon and  object is 60
The sun  altitude  is -55.4 degree.
The object can be observed till sunrise at 2018-07-04 05:38:26

MASTER-OAFA robotic telescope (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  GRB180703A 14975 sec after trigger 
time at 2018-07-04 01:11:15 UT. On our first (180s exposure)  set we 
found 6 optical transient within LAT error-box (ra=6.5375 dec=-67.0894 
r=0.3039) brighter then 14.7.


The observations made on zenit distance = 76 degrees, galaxy latitude b = 
-50 degree.
The moon (72 % bright part) below the horizon (The altitude of the Moon is 
-18 degree ).
The sun  altitude  is -43.1 degree.
The object can be observed till sunrise at 2018-07-04 11:36:37


The visibility GRB error box (coord: 349.9500 -65.5800 error_box: 0.3) 
at trigger time at different MASTER sites:


obj: -42.33 sun: -21.55 - Tavrida (Crimea, Russia) 
obj: -41.44 sun: -11.38 - IAC, Teide, (Tenerife, Spain)
obj:  28.43 sun: -66.35 - SAAO (Sutherland, SA) 
obj: -31.89 sun: -23.27 - Kislovodsk (Russia)
obj: -38.98 sun: -9.15 -  Ural(Kourovka, Russia)
obj: -27.62 sun:  0.11 -  Tunka (near Baykal Lake, Russia) 
obj: -26.46 sun: 12.65 -  Amur(Blagoveschensk)
obj:  7.39 sun:  7.00 -   OAFA (Argentina)

The message may be cited.


GRB_name: GRB180703A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22927
SUBJECT: Konus-Wind observation of GRB 180703A
DATE:    18/07/08 12:38:41 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

D. Frederiks, S. Golenetskii, R.Aptekar, A. Kozlova,
A.Lysenko,  D. Svinkin, A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The long GRB 180703A (IPN Triangulation: Hurley et al., GCN 22925;
Fermi-LAT detection: Racusin et al., GCN 22883;
Fermi-GBM detection: Poolakkil & Meegan, GCN 22896)
triggered Konus-Wind at T0=75705.256 s UT (21:01:45.256)/

The burst light curve shows a single, FRED-like pulse
with a total duration of ~50 s. Also, there is a weak
count rate increase in the softest KW light curve around T0 + 170 s.
The emission in the main peak is seen up to ~10 MeV.

As observed by Konus-Wind, the burst had a fluence of
(4.1 Â± 1.0)x10^-5 erg/cm2 and a 64-ms peak energy flux,
measured from T0+1.728, of (8.9 Â± 1.3)x10^-6 erg/cm2
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+49.408 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 = -0.85 (-0.21,+0.33),
the high energy photon index beta = -1.89 (-0.37,+0.19),
the peak energy Ep = 367 (-136,+196) keV,
chi2 = 89/97 dof.

The spectrum near the peak count rate (measured from T0
to T0+8.448 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 = -0.73 (-0.17,+0.20),
the high energy photon index beta = -1.90 (-0.22,+0.13),
the peak energy Ep = 407 (-97,+147) keV,
chi2 = 88/97 dof.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB180703_T75705/

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


GRB_name: GRB180705A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22929
SUBJECT: GRB 180705A: RTT150 optical upper limit
DATE:    18/07/08 16:42:54 GMT
FROM:    Rodion Burenin at IKI, Moscow  <rodion@hea.iki.rssi.ru>

I. Bikmaev, E. Irtuganov, N. Sakhibullin (KFU/AST),
R. Burenin, M. Pavlinsky, R. Sunyaev (IKI),
I. Khamitov, S. Ozdemir (TUG), E. Gogus (Sabanci Uni.)

report:

We observed the field of GRB 180705A (Stamatikos et al., GCN 22902)
with the Russian-Turkish 1.5-m optical telescope (RTT150, Bakirlitepe,
TUBITAK National Observatory, Turkey) using the TFOSC instrument.

We obtained series of Rc exposures in July 05, 2018 (6 frames x 600
sec, UT = 19:12 - 20:19), ~ 4 hours after the burst. Within enhanced
Swift-XRT position (Goad et al., GCN 22906) we have not detected any
object down to Rc =~ 23.5 mag in the combined image (calibrated
against SDSS secondary standard stars).  Our result confirms OT
non-detections as published in other GCNs (Lipunov et al., GCN 22904,
Watson et al., GCN 22911, Breeveld et al., GCN 22912, Mazaeva et al.,
GCN 22913).


GRB_name: GRB180709A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22930
SUBJECT: GRB 180709A: Swift detection of a burst
DATE:    18/07/09 11:11:25 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC), S. D. Barthelmy (GSFC),
A. D'Ai (INAF-IASFPA), V. D'Elia (ASDC), P. A. Evans (U Leicester),
J. A. Kennea (PSU), N. P. M. Kuin (UCL-MSSL), A. Y. Lien (GSFC/UMBC)
and K. L. Page (U Leicester) report on behalf of the Neil Gehrels
Swift Observatory Team:

At 10:52:00 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180709A (trigger=846868).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 38.119, +60.372 which is 
   RA(J2000) = 02h 32m 29s
   Dec(J2000) = +60d 22' 18"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multi-peaked
structure with a duration of about 30 sec.  The peak count rate
was ~800 counts/sec (15-350 keV), at ~6 sec after the trigger. 

The XRT began observing the field at 10:53:45.0 UT, 104.8 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source with an enhanced position: RA, Dec
38.1178, 60.3490 which is equivalent to:
   RA(J2000)  = 02h 32m 28.27s
   Dec(J2000) = +60d 20' 56.5"
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This
location is 82 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 http://www.swift.ac.uk/sper. No
spectrum from the promptly downlinked event data is yet available to
determine the column density. 

The initial flux in the 2.5 s image was 6.60e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 114 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. 

Burst Advocate for this burst is F. E. Marshall (marshall AT milkyway.gsfc.nasa.gov). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB180703A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22931
SUBJECT: GRB 180703A: Swift-XRT afterglow detection
DATE:    18/07/09 13:33:20 GMT
FROM:    Antonino D'Ai at IASF-PA  <antonino.dai@ifc.inaf.it>

S.L. Gibson (U. Leicester), Z. Liu (NAOC / U. Leicester), P. D'Avanzo
(INAF-OAB), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), S. J. LaPorte
(PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), J.P. Osborne
(U. Leicester) and P.A. Evans (U. Leicester) report on behalf of the
Swift-XRT team:

Swift-XRT has conducted further observations of the field of the
Fermi/LAT-detected burst GRB 180703A (Racusin et al. GCN Circ. 22883).
The observations now extend from T0+17.3 ks to T0+263.7 ks. The source
previously reported by Gibson et al. (GCN Circ. 22891), "Source 1", is 
believed to be the afterglow.  The position of this source is RA,
Dec=6.4699, -67.1802 which is equivalent to:

RA (J2000): 00:25:52.79
Dec(J2000): -67:10:48.7

with an uncertainty of 4.8 arcsec (radius, 90% confidence).  This
position is 5.7 arcmin from the Fermi/LAT position.  The source is
fading with alpha >0.8.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00020797.
The results of the full analysis of the tiled XRT observations are
available at http://www.swift.ac.uk/xrt_products/TILED_GRB00070.

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


GRB_name: GRB180703B
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22932
SUBJECT: GRB 180703B: further analysis of CGBM data
DATE:    18/07/09 14:07:10 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

V. Pal'shin, Y. Kawakubo, A. Yoshida, T. Sakamoto, S. Sugita, A. Tezuka,
S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

Using the CALET Gamma-ray Burst Monitor (CGBM) event data
we report further analysis of the bright, short-duration, soft spectrum
GRB 180703B (Fermi-LAT detection: Racusin et al. GCN Circ. 22884;
CGBM detection: Takahashi et al. GCN Circ. 22888;
Fermi-GBM detection: Poolakkil and Meegan GCN Circ. 22897;
IPN localization: Hurley et al. GCN Circ. 22908;
Konus-Wind observation: Frederiks et al. GCN Circ. 22914).

Using a 16-ms binned light curve of the sum of HXM1 and HXM2 detectors,
the estimated spectral lag for the 25-50 keV to 100-300 keV bands is
43 Â± 30 ms (68% CL).  This value is more consistent with lags of long rather
than short GRBs.

We also obtained more precise estimates of T90 and T50 using the SGM 16-ms lc:
1.44 s +- 0.10 s and 0.34 +- 0.06 sec (40-1000 keV), respectively.

The time-averaged spectrum of the burst (measured by the SGM from T0+0.032 sec
to T0+1.856 sec, where T0=22:46:51.183 UTC) is best fit in the 30-1000 keV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.83(-0.32, +0.36) and Ep = 143(-13, +15) keV (chi2 = 62/59 dof).
The resulting fluence in this energy range is 5.98(-0.43, +0.46)x10^-6 erg/cm2.
The quoted errors are at 90% CL.

All the quoted values are preliminary.


GRB_name: GRB180709A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22933
SUBJECT: GRB 180709A: Enhanced Swift-XRT position
DATE:    18/07/09 14:25:14 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

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

Using 1493 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 180709A, 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 = 38.11784, +60.34912 which is equivalent
to:

RA (J2000): 02h 32m 28.28s
Dec (J2000): +60d 20' 56.8"

with an uncertainty of 1.8 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: GRB180709A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22934
SUBJECT: GRB 180709A: COATLI Optical Observations
DATE:    18/07/09 15:27:42 GMT
FROM:    Nat Butler at Az State U  <natbutler@asu.edu>

Nat Butler (ASU), Alan M. Watson (UNAM), aRosa L. Becerra (UNAM), William
H. Lee (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Alexander Kutyrev (GSFC), and
Eleonora Troja (GSFC) report:

We observed the field of GRB 180709A (Marshall et al., GCN Circ 22930) with
the COATLI 50-cm telescope and interim imager at the Observatorio
AstronÃ³mico Nacional on the Sierra de San Pedro MÃ¡rtir (
http://coatli.astroscu.unam.mx) from 2018-07-09 10:53:05.6 to 11:26:07.1
UTC (from 65.4 seconds after the trigger or 14.5 seconds after the alert to
0.55 hours after the trigger), obtaining a total of 695 seconds of exposure
in the w filter.

For a source within the XRT error region (Marshall et al., GCN Circ.
22930), we determine a 3-sigma upper limit of

 w > 21.3

This magnitude is calibrated against the USNO-B1 catalog (adjusted to an
approximate AB system) and is not corrected for Galactic extinction in the
direction of the GRB.

We thank the COATLI technical team (Fernando Ãngeles, Oscar Chapa, Salvador
Cuevas, Alejandro Farah, Jorge Fuentes, RosalÃ­a Langarica, Fernando QuirÃ³s,
and Carlos Tejada) and the staff of the Observatorio AstronÃ³mico Nacional.


GRB_name: GRB180709A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22935
SUBJECT: GRB 180709A: Optical limits
DATE:    18/07/09 16:36:22 GMT
FROM:    Jules Halpern at Columbia U.  <jph1@columbia.edu>

J. P. Halpern (Columbia U.) reports:

I observed the field of Swift GRB 180709A (Marshall et al., GCN 22930)
with an SDSS r filter using the 1.3m McGraw Hill telescope of the
MDM Observatory, beginning 17.6 minutes after the trigger.
Four 5-minute exposures were obtained in morning twilight.
Upper limits at the enhanced Swift-XRT position of Beardmore et al.
(GCN 22933) are listed below, as calibrated to Pan-STARRS1 photometry.

       ---------------------------------------------
        Date(UT)  Start(UT)  Mid-time T-T0   r(mag)
       ---------------------------------------------
        July 9     11:09:34      1194 s      > 22.0
        July 9     11:14:41      1501 s      > 21.8
        July 9     11:19:47      1807 s      > 21.4
        July 9     11:24:54      2114 s      > 21.1
       ---------------------------------------------

These magnitudes are not corrected for Galactic extinction, which is
considerable at this Galactic latitude of -0.1 deg.  According to the
NED implementation of Schlafly & Finkbeiner (2011), A_r = 6.1 mag.


GRB_name: GRB180709A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22936
SUBJECT: GRB 180709A: Swift-XRT refined Analysis
DATE:    18/07/09 20:08:00 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

S. J. LaPorte (PSU), J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU),
P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester), Z. Liu (NAOC /
U. Leicester), V. D'Elia (ASDC), A. D'Ai (INAF-IASFPA), A. Melandri
(INAF-OAB) and F.E. Marshall report on behalf of the Swift-XRT team:

We have analysed 6.8 ks of XRT data for GRB 180709A (Marshall et al.
GCN Circ. 22930), from 111 s to 24.8 ks after the  BAT trigger. The
data comprise 277 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Beardmore et al. (GCN Circ. 22933).

The light curve can be modelled with a power-law decay with a decay
index of alpha=1.95 (+0.09, -0.08).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.41 (+/-0.20). The
best-fitting absorption column is  1.9 (+/-0.4) x 10^22 cm^-2, in
excess of the Galactic value of 8.9 x 10^21 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.7 (+0.5, -0.4) and
a best-fitting absorption column of 3.5 (+1.2, -1.0) x 10^22 cm^-2. The
counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 8.4 x 10^-11 (1.6 x 10^-10) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      3.5 (+1.2, -1.0) x 10^22 cm^-2
Galactic foreground: 8.9 x 10^21 cm^-2
Excess significance: 4.3 sigma
Photon index:      1.7 (+0.5, -0.4)

If the light curve continues to decay with a power-law decay index of
1.95, the count rate at T+24 hours will be 2.1 x 10^-5 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.8 x
10^-15 (3.4 x 10^-15) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00846868.

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


GRB_name: GRB180709A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22937
SUBJECT: GRB 180709A: Swift/UVOT Upper Limits
DATE:    18/07/09 20:38:53 GMT
FROM:    Alice Breeveld at MSSL-UCL  <a.breeveld@ucl.ac.uk>

A. A. Breeveld (UCL-MSSL), S. W. K. Emery (UCL-MSSL) and F. E. Marshall 
(NASA/GSFC) report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180709A 
115 s after the BAT trigger (Marshall et al., GCN Circ. 22930).
No optical afterglow consistent with the XRT position (Beardmore et al., 
GCN Circ. 22933) 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           115          264          147         >20.5
u_FC               273          523          246         >19.6
v                  604          797           39         >18.0
b                  529          723           39         >19.0
uvw1               654          846           39         >17.7

The magnitudes in the table are not corrected for the Galactic 
extinction due to the reddening of E(B-V) = 2.72 in the direction of the 
burst (Schlegel et al. 1998).


GRB_name: GRB180709A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22938
SUBJECT: GRB 180709A: Swift-BAT refined analysis
DATE:    18/07/09 20:48:13 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

M. Stamatikos (OSU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
F. E. Marshall (NASA/GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), T. N. Ukwatta (LANL)
(i.e. the Swift-BAT team):

Using the data set from T-240 to T+963 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 180709A (trigger #846868)
(Marshall et al., GCN Circ. 22930).  The BAT ground-calculated position is
RA, Dec = 38.086, 60.333 deg which is
  RA(J2000)  =  02h 32m 20.7s
  Dec(J2000) = +60d 19' 59.4"
with an uncertainty of 1.6 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 81%.

The mask-weighted light curve shows a single-peaked structure that starts
at ~T0 and peaks at ~T+10 s. The main structure ends at ~T+40 s, with some
tail emission lasting till ~T+240 s. T90 (15-350 keV) is 215.1 +- 28.9 sec
(estimated error including systematics).

The time-averaged spectrum from T+0.54 to T+243.46 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.37 +- 0.23.  The fluence in the 15-150 keV band is 1.4 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T+8.73 sec in the 15-150 keV band
is 0.6 +- 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/846868/BA/


GRB_name: GRB180709A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22939
SUBJECT: GRB 180709A: BOOTES-5/JGT optical observations
DATE:    18/07/09 21:54:44 GMT
FROM:    Irene Carrasco at Inst.De Astrofisica de Andalucia  <irene@iaa.es>

I. Carrasco (Univ. de Malaga), Y. Hu, E. Fernandez-Garcia, J. C. Tello 
and A. J. Castro-Tirado (IAA-CSIC), D. Hiriart and
W. H. Lee (UNAM), S. Jeong and I. H. Park (SKKU), M. D. Caballero-Garcia 
(ASU-CAS, CZ) and R. Cunniffe (Inst. of Physics, CZ) on behalf of a 
larger collaboration, report:

The 60 cm BOOTES-5/JGT at Observatorio Astronomico Nacional in San Pedro 
Martir (Mexico) automatically responded in 21s (and 74s after the GRB 
onset) to the Swift trigger of GRB 180709A (Marshall et al., GCN  
22930). The first unfiltered images (10 s exposures) were obtained at 
10:53:14 UT. At the position of the Swift X-ray afterglow, no optical 
afterglow is detected down 18.1 mag. Furthermore, on the co-add of the 
images obtained until 11:43:04 UT no afterglow is detected down to 21 
mag, consistent with the limits reported by Butler et al. (GCN 22934), 
Halpern (GCN 22935) and Breeveld et al. GCN 22937).

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


GRB_name: GRB180705A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22941
SUBJECT: GRB 180705A: OSN observations
DATE:    18/07/11 19:25:41 GMT
FROM:    Alexander Kann at IAA-CSIC  <kann@iaa.es>

D. A. Kann, L. Izzo (both HETH/IAA-CSIC), and A. Sota (IAA/CSIC) report 
on behalf of HETH:

We observed the field of GRB 180705A (Stamatikos et al., GCN #22902) 
with the 1.5-m OSN telescope in Granada, Spain.

We obtained 20 x 300 s images in the Ic band centered at 0.262416 days 
(6.3 hrs) after the GRB.

At the XRT position of the GRB (Goad et al., GCN #22906), there is a 
possible faint source, formally detected at Ic (Vega) = 23.6 +/- 0.2 
mag. We note, however, that the background of the image is structured 
because of the proximity of the bright star HD 123921 (V ~ 9 mag), 
therefore the detection may be spurious. The formal 3 sigma upper limit 
is Ic > 24 mag, also possibly overestimated.

Even if the source we detect is not real, any afterglow of this GRB is 
clearly very faint, in agreement with other non-detection reports 
(Lipunov et al., GCN #22904, Watson et al., GCN #22911, Breeveld et al., 
GCN #22912, Mazaeva et al., GCN #22913, Bikmaev et al., GCN #22929).

The field was calibrated against SDSS secondary standard stars using the 
transformation of Lupton (2005).


GRB_name: GRB180711A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22943
SUBJECT: GRB 180711A: CALET Gamma-Ray Burst Monitor detection
DATE:    18/07/13 04:07:39 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

S. Ozawa (Waseda U), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita, Y. Kawakubo,
A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
Y. Asaoka, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The weak GRB 180711A (INTEGRAL SPI-ACS trigger 8101; Konus-Wind
trigger time on 17:02:02.37 UT) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 17:02:00.439 UTC on 11 July 2018.
The burst signal was seen only by the CGBM SGM detector.

The burst light curve shows a single pulse which starts
at T+0.6 sec, peaks at ~T+2.1 sec, and ends at T+5.3 sec.
The T90 and the T50 durations measured by the SGM data are
4.3 +- 0.6 sec and 2.5 +- 0.6 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1215363620/

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


GRB_name: GRB180703A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22944
SUBJECT: GRB 180703A: optical afterglow confirmation
DATE:    18/07/13 11:55:46 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi, R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell 
(U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU), A. Cucchiara, 
D. Morris (U. of Virgin Islands) on behalf of a large collaboration report:

We observed Fermi-LAT GRB 180703A (Racusin et al. GCN 22883) with the 
LCO 2-m unit in Hawaii (former FTN) on July 12, 17:46 UT (8.9 days after 
the GRB trigger time) with the SDSS i' filter. We do not detect the 
optical candidate (Guidorzi et al. GCN 22892) found on the border of the 
Swift-XRT error circle of the confirmed X-ray afterglow (Gibson et al. 
GCN 22931) down to a limit magnitude of i'> 22.0 with a 5x120s exposure. 
We therefore confirm the nature of optical afterglow of the candidate. A 
comparison between the images taken at both epochs is available at the 
link below.

http://www.fe.infn.it/u/guidorzi/new_guidorzi_files/180703A_OT.png


GRB_name: GRB180714A
Detection_method: INTEGRAL
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22946
SUBJECT: GRB180714A: a long GRB detected by INTEGRAL
DATE:    18/07/14 14:02:50 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 30 s has been detected by IBAS in the
IBIS/ISGRI data at 13:01:15 UT of 2018 July 14.

The refined coordinates (J2000) are:

R.A.= 242.9191 deg
DEC.= 33.2811  deg

with an uncertainty of 2.5    arcmin (90% c.l.).

The burst had a peak flux of  0.3    counts/cm2/s (20-200 keV, 1-s
integration  time) and a fluence in the same energy range of about 3x10^-7
erg/cmq.

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


GRB_name: GRB180715A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22947
SUBJECT: GRB 180715A: Swift detection of a short hard burst
DATE:    18/07/15 18:15:11 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
S. W. K Emery (UCL-MSSL), J.D. Gropp (PSU), S. J. LaPorte (PSU),
A. Y. Lien (GSFC/UMBC), Z. Liu (NAOC/U. Leicester),
D. M. Palmer (LANL) and A. Tohuvavohu (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 18:07:05 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180715A (trigger=848048).  Swift could not immediately
slew to the location due to the Earth limb constraint. 
The BAT on-board calculated location is 
RA, Dec 235.069, -0.925 which is 
   RA(J2000) = 15h 40m 17s
   Dec(J2000) = -00d 55' 28"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a single short
peak structure with a duration of about 0.7 sec.  The peak count rate
was ~6000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

Due to an observing constraint, Swift will not slew until T0+50.9
minutes. There will be no XRT or UVOT data until this time. 

Burst Advocate for this burst is T. N. Ukwatta (tilan.ukwatta 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/too.html.)


GRB_name: GRB180715A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22948
SUBJECT: GRB 180715A: Swift-XRT observations
DATE:    18/07/15 19:54:22 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

S. Campana (INAF-OAB), G. Cusumano (INAF-IASF PA), P.A. Evans (U.
Leicester), J.P. Osborne (U. Leicester), D.N. Burrows (PSU) and J.A.
Kennea (PSU) report on behalf of the Swift-XRT team:

The XRT began observing the field of GRB 180715A at 18:59:52.8 UT,
3167.8 seconds after the BAT trigger. No source was detected in 1.1 ks
of promptly downlinked data, which covered 73% of the BAT error circle.
We are waiting for the full dataset to detect and localise the XRT
counterpart.


GRB_name: GRB180715A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22949
SUBJECT: GRB 180715A: LCO Sutherland possible optical candidate
DATE:    18/07/15 19:58:20 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi, R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell 
(U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU), A. Cucchiara, 
D. Morris (U. of Virgin Islands) on behalf of a large collaboration report:

One of the LCO 1-m units at Sutherland Observatory (South Africa) 
automatically began observing Swift GRB 180715A (Ukwatta et al. GCN 
22947) on July 15, 18:17:37 UT (10.5 minutes after the GRB trigger time) 
with the SDSS r' filter. Within the Swift-BAT error circle, well within 
the glare of a 8-mag catalogued object we clearly detect a source which 
is not present in the SDSS catalogue at the following position:

RA(J2000)=  15:40:22.30
DEC(J2000)= -00:54:44.4

with an error radius of ~1".


GRB_name: GRB180715A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22950
SUBJECT: GRB 180715A: GOTO optical limits
DATE:    18/07/15 23:27:04 GMT
FROM:    Joe Lyman at U of Warwick  <j.d.lyman@warwick.ac.uk>

J.Lyman, D.Steeghs (U. Warwick), G.Ramsay (Armagh O.), M.Dyer
(U. Sheffield), K.Ulaczyk, B.Gompertz, A.Levan, R.Cutter (U. Warwick)
K. Ackley, D.Galloway, E.Rol (Monash U.), V.Dhillon (U. Sheffield),
P.O'Brien, N.Tanvir (U. Leicester), S.Poshyachinda (NARIT),
D.Pollacco (U. Warwick), E.Thrane (Monash U.)

report on behalf of the GOTO collaboration:

In response to GRB 180715A (Ukwatta et al. GCN 22947), the
Gravitational-wave Optical Transient Observer (GOTO) observed the
field near the Swift BAT detection.

Observations started at 2018-07-15T22:37:10 UT (4.5 hours after the
burst) consisted of a set of 3x120s exposures in our wide L filter
(400-700nm). We detect the source identified by Guidorzi et al.
(GCN 22949) but note that this source appears in PanSTARRS
images of the field and in the Gaia catalogue and is thus likely to
be unrelated. We did not detect any other uncatalogued source within
the BAT localisation uncertainty. A preliminary analysis of the stacked
image was used to derive a 5-sigma upper limit of V>20.5 mag.


GOTO is operated at the La Palma observing facilities of the University
of Warwick on behalf of a consortium including the University of
Warwick, Monash University, Armagh Observatory, the University of
Leicester, the University of Sheffield, the National Astronomical
Research Institute of Thailand (NARIT) and the Instituto de Astrofisica
de Canarias (IAC)

https://goto-observatory.org/


GRB_name: GRB180715A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22951
SUBJECT: GRB 180715A: Swift-BAT refined analysis
DATE:    18/07/16 00:39:59 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

T. N. Ukwatta (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA),
A. Y. Lien (GSFC/UMBC), 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 180715A (trigger #848048)
(Ukwatta et al., GCN Circ. 22947).  The BAT ground-calculated position is
RA, Dec = 235.085, -0.899 deg which is
  RA(J2000)  =  15h 40m 20.5s
  Dec(J2000) = -00d 53' 57.6"
with an uncertainty of 2.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 85%.

The mask-weighted light curve shows a double-peaked structure that starts
at ~T-0.1 and ends at ~T+0.6, The two peaks occur at ~T+0.1 and ~T+0.5,
respectively. T90 (15-350 keV) is 0.68 +- 0.09 sec (estimated error including
systematics).

The time-averaged spectrum from T-0.14 to T+0.63 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
0.74 +- 0.27.  The fluence in the 15-150 keV band is 1.3 +- 0.2 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.26 sec in the 15-150 keV band
is 1.2 +- 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/848048/BA/


GRB_name: GRB180715A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22952
SUBJECT: GRB 180715A: Fermi GBM detection
DATE:    18/07/16 04:35:23 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 18:07:05.06 UT on 15 July 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180715A (trigger 553370830 / 180715755)
which was also detected by the Swift/BAT (Ukwatta et al. 2018, GCN 22947).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 75
degrees.

The GBM light curve shows a single structured peak
with a duration (T90) of about 0.7 s (50-300 keV).
The time-averaged spectrum from T0-0.19 to T+0.51 s is
adequately fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.14 +/- 0.21 and
the cutoff energy, parameterized as Epeak, is 852 +/- 182 keV.

The event fluence (10-1000 keV) in this time interval is
(1.7 +/- 0.1)E-06 erg/cm^2. The 64-ms peak photon flux measured
starting from T0-0.064s in the 10-1000 keV band
is 8.4 +/- 1.3 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB180715A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22953
SUBJECT: GRB 180715A: Swift-XRT observations
DATE:    18/07/16 23:29:17 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

J.A. Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), S.L. Gibson (U.
Leicester), Z. Liu (NAOC / U. Leicester), J.P. Osborne (U. Leicester),
A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB),
D.N. Burrows (PSU) and T. N. Ukwatta (LANL) report on behalf of the
Swift-XRT team:

We have analysed 14 ks of Photon Counting (PC) mode XRT data for the
Swift/BAT-detected burst GRB 180715A (Ukwatta et al. GCN Circ. 22951),
collected between T0+11.0 ks and T0+67.7 ks. 

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


The 3-sigma upper limit at the BAT position is 9.5x10^-4 ct/sec.

Details of these sources are given below:

Source 5:
  RA (J2000):  235.1362  =  15:40:32.68
  Dec (J2000): -0.9559  =  -00:57:21.2
  Error: 6.1 arcsec (radius, 90% conf.)
  Count-rate: (5.4 [+2.7, -2.1])e-4 ct s^-1   
  Distance: 266 arcsec from Swift/BAT position.

Source 7:
  RA (J2000):  235.0967  =  15:40:23.21
  Dec (J2000): -0.9760  =  -00:58:33.6
  Error: 5.4 arcsec (radius, 90% conf.)
  Count-rate: (7.4 [+3.2, -2.6])e-4 ct s^-1   
  Distance: 210 arcsec from Swift/BAT position.

Source 8:
  RA (J2000):  235.1256  =  15:40:30.15
  Dec (J2000): -0.8791  =  -00:52:44.8
  Error: 6.5 arcsec (radius, 90% conf.)
  Count-rate: (8.2 [+3.3, -2.7])e-4 ct s^-1   
  Distance: 261 arcsec from Swift/BAT position.
  Flux: (5.6 [+2.3, -1.8])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 10:
  RA (J2000):  234.9980  =  15:39:59.51
  Dec (J2000): -0.9504  =  -00:57:01.5
  Error: 5.0 arcsec (radius, 90% conf.)
  Count-rate: (1.85 [+0.46, -0.42])e-3 ct s^-1  
  Distance: 272 arcsec from Swift/BAT position.
  Flux: (8.9 [+2.2, -2.0])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 11:
  RA (J2000):  235.0291  =  15:40:6.98
  Dec (J2000): -0.9196  =  -00:55:10.6
  Error: 10.7 arcsec (radius, 90% conf.)
  Count-rate: (4.4 [+2.5, -2.0])e-4 ct s^-1   
  Distance: 144 arcsec from Swift/BAT position.

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

The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
http://www.swift.ac.uk/ToO_GRBs/00848048.

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


GRB_name: GRB180715A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22954
SUBJECT: GRB 180715A: COATLI Optical Observations 
DATE:    18/07/17 04:44:52 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), William
H. Lee (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Alexander Kutyrev (GSFC), and
Eleonora Troja (GSFC) report:

We observed the field of the short GRB 180715A (Ukwatta et al., GCN Circ.
22947) with the COATLI 50-cm telescope and interim imager at the
Observatorio AstronÃ³mico Nacional on the Sierra de San Pedro MÃ¡rtir 
(http://coatli.astroscu.unam.mx) from 2018-07-16 03:40:25 to 08:07:12 UTC
(9.55 to 14.00 hours after the trigger), obtaining a total of 3.33 hours
of exposure in the w filter.

We do not detect any optical sources coincident with the five X-ray
sources reported by Kennea et al. (GCN Circ. 22953) to a 5-sigma limiting
magnitude of

w > 22.4

This magnitude is calibrated against the USNO-B1 catalog (adjusted to an
approximate AB system) and is not corrected for Galactic extinction in
the direction of the GRB.

We thank the COATLI technical team (Fernando Ãngeles, Oscar Chapa,
Salvador Cuevas, Alejandro Farah, Jorge Fuentes, RosalÃ­a Langarica,
Fernando QuirÃ³s, and Carlos Tejada) and the staff of the Observatorio
AstronÃ³mico Nacional.


GRB_name: GRB180715A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22955
SUBJECT: GRB 180715A: LCO Sutherland observations
DATE:    18/07/17 09:43:53 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi, R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell 
(U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU), A. Cucchiara, 
D. Morris (U. of Virgin Islands) on behalf of a large collaboration report:

With reference to the observation of our previous report (Guidorzi et 
al. GCN 22949), within the XRT error circles of the five X-ray sources 
(Kennea et al. GCN 22953) we found no uncatalogued source down to 
r'>20.0 mag at a mid time of 0.28 hours after the GRB trigger time 
(5x120s exposure), as calibrated against nearby SDSS objects.


GRB_name: GRB180715A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22956
SUBJECT: GRB 180715A: CALET Gamma-Ray Burst Monitor detection
DATE:    18/07/18 06:03:29 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

S. Torii (Waseda U), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita, Y. Kawakubo,
A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The short, hard GRB 180715A (Swift-BAT trigger #848048:
Ukwatta, et al., GCN Circ. 22947, 22951; Fermi-GBM detection:
Hamburg and Meegan, GCN Circ. 22952) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 18:07:04.799 UTC on 15 July 2018.
The burst signal was seen by all CGBM detectors.

The burst light curve shows a double-peaked pulse which starts
at T+0.192 sec and ends at T+0.784 sec.
The T90 and the T50 durations measured by the SGM data are
0.53 +- 0.07 sec and 0.34 +- 0.12 sec (40-1000 keV), respectively.

The time-averaged spectrum of the burst (measured by the SGM from
T+0.192 sec to T+0.784 sec) is best fit in the 0.03-10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -0.64(-0.37, +0.46) and Ep = 707(-195, +337) keV (chi2 = 29.4/32 dof).
The resulting fluence in this energy range is 2.32(-0.50, +0.65)x10^-6 erg/cm2.
The quoted errors are at 90% CL.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1215713118/

All the quoted values are preliminary.

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


GRB_name: GRB180718A
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22959
SUBJECT: GRB 180718A short GRB detected by IPN and found in ground analysis of BAT data
DATE:    18/07/18 23:38:33 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin and K. Hurley, on behalf of the IPN,

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

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

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,
report:

The short-duration GRB 180718A was detected by
Fermi (GBM; trigger 553571869), INTEGRAL (SPI-ACS), and Swift (BAT),
at about 7065 s UT (01:57:45).

We have triangulated this GRB to a GBM-INTEGRAL annulus centered at
RA(2000)=260.736 deg (17h22m57s) Dec(2000)=+48.285 deg (+48d17'07"),
whose radius is 79.182 +/- 2.067 deg (3 sigma).

 From the ground analysis using the available Swift/BAT event data
from T-1 to T+2 sec, we found a 6.3 sigma detection in an image with
intervals from T0-0.026 s to T0+0.165 s and energy range 15-150 keV,
where T0 = 2018-07-18 01:57:44.530 UTC.

The BAT ground-calculated position of this detection is
RA, Dec = 336.019, 2.790 deg which is
    RA(J2000)  =  22h 24m 04.6s
    Dec(J2000) = +02d 47' 23.3"
with an uncertainty of 3.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 25%.
The position is consistent with the annulus.

The BAT mask-weighted light curve shows
a single-pulse structure that starts at ~T0 and ends at ~T+0.1 s.
T90 (15-350 keV) is 0.08 +- 0.02 sec (estimated error including 
systematics).

Due to the weakness of this burst, the BAT spectrum is
not well-constrained. However, the burst seems to be relatively soft
comparing to regular short GRBs.

The results of the batgrbproduct analysis are available at
https://gcn.gsfc.nasa.gov/notices_s/848489/BA/

A ToO observation with Swift/XRT has been requested.


GRB_name: GRB180718A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22960
SUBJECT: GRB 180718A: Fermi GBM detection
DATE:    18/07/19 03:53:43 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

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

"At 01:57:44.60 UT on 18 July 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180718A (trigger 553571869 / 180718082),
which was also detected by the INTEGRAL SPI-ACS and subsequently
localized by IPN. Ground analysis of the Swift/BAT data revealed
a detection consistent with the IPN annulus (GCN 22959).

The angle from the Fermi LAT boresight at the GBM trigger time is 61
degrees.

The GBM light curve consists of a single peak
with a duration (T90) of about 0.08 s (50-300 keV).
The time-averaged spectrum from T0-0.06 s to T0+0.02 s is
adequately fit by a Band function with Epeak = 187 +/- 61 keV,
alpha = -0.2 +/- 0.4, and beta = -2.3 +/- 0.5.

The event fluence (10-1000 keV) in this time interval is
(2.3 +/- 0.3)E-07 erg/cm^2. The 64-ms peak photon flux measured
starting from T0-0.05 s in the 10-1000 keV band
is 9 +/- 1 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB180718B
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22961
SUBJECT: GRB 180718B: Fermi-LAT detection
DATE:    18/07/19 04:24:04 GMT
FROM:    Judith Racusin at GSFC  <judith.racusin@nasa.gov>

M. Crnogorcevic (NASA/GSFC/UMD), G. Vianello (Stanford), J. L. Racusin (NASA/GSFC), 
M. Axelsson (KTH and Stockholm University), and E. Bissaldi (Politecnico and INFN Bari), report 
on behalf of the Fermi-LAT team:

At 18:18:24.46 UT on July, 18, 2018 Fermi-LAT detected high-energy emission from GRB 180718B, 
which was also detected by Fermi-GBM (trigger 553630709 / 180718763). 

The best LAT on-ground location is found to be
RA, Dec = 44.68, -31.5 (J2000)

with an error radius of 0.65 deg (90% containment, statistical error only). 

This was 50 deg from the LAT boresight at the time of the trigger.

The data from the Fermi-LAT show a significant increase in the event rate that is spatially and 
temporally correlated with the trigger with high significance. 

The highest-energy photon is a 300 MeV event which is observed 17 seconds after the GBM trigger.

A Swift ToO has been requested for this burst.

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: GRB180718B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22962
SUBJECT: GRB 180718B: Swift ToO observations
DATE:    18/07/19 05:01:17 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 180718B. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020803

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: GRB180718A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22963
SUBJECT: GRB 180718A: Swift ToO observations
DATE:    18/07/19 08:58:17 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 GRB 180718A. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020802

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 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: GRB180716A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22964
SUBJECT: GRB 180716A: CALET Gamma-Ray Burst Monitor detection
DATE:    18/07/19 10:26:47 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

Y. Shimizu (Kanagawa U), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita, Y. Kawakubo,
A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
T. Tamura (Kanagawa U), W. Ishizaki (ICRR), M. L. Cherry (LSU),
S. Ricciarini (U of Florence), A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The short GRB 180716A (Konus-Wind trigger time on 19:27:20.845 UT)
triggered the CALET Gamma-ray Burst Monitor (CGBM) at 19:27:24.372 UTC
on 16 July 2018. This GRB is also clearly seen by the publicly available
INTEGRAL SPI-ACS light curve.
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 signal was seen only by the SGM instrument.

The burst light curve shows a structured pulse which starts
at T-0.38 sec, peaks at T-0.13 sec, and ends at T+0.26 sec.
There is a weaker pulse marginally seen at ~T-0.9 sec.
The T90 and the T50 durations measured by the SGM data are
0.58 +- 0.18 sec and 0.26 +- 0.18 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1215804335/

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


GRB_name: GRB180718B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22965
SUBJECT: GRB 180718B: Fermi GBM detection
DATE:    18/07/19 14:07:31 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 18:18:24.46 UT on 18 July 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180718B (trigger 553630709 / 180718763).
which was also detected by the Fermi LAT (Racusin et al. 2018, GCN 22961).
The GBM on-ground location is consistent with the LAT position.

The angle from the Fermi LAT boresight at the GBM trigger time is 48
degrees.

The GBM light curve shows a structured FRED-like peak
with a duration (T90) of about 98 s (50-300 keV).
The time-averaged spectrum from T0+0 s to T0+66 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.73 +/- 0.05 and
the cutoff energy, parameterized as Epeak, is 761 +/- 78 keV.
A Band function also fits the spectrum with Epeak = 731 +/- 83 keV,
alpha = -0.71 +/- 0.05,and beta = -2.79 +/- 0.73.

The event fluence (10-1000 keV) in this time interval is
(2.6 +/- 0.1)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.6 s in the 10-1000 keV band
is 3.6 +/- 0.2 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB180715A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22967
SUBJECT: GRB 180715A: Swift/UVOT Upper Limits
DATE:    18/07/19 15:46:40 GMT
FROM:    Mike Siegel at PSU/Swift MOC  <siegel@swift.psu.edu>

M. H. Siegel (PSU) and T. N. Ukwatta (LANL)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180715A
4312 s after the BAT trigger (Ukwatta et al., GCN Circ. 22947).
No optical afterglow consistent with the BAT position (Ukwatta et al., GCN
Circ. 22951) 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          4312         4462          147         >20.6
white             4312         5695          344         >21.0
v                 4469         4669          197         >19.1
b                 5290         5490          197         >20.1
u                 5085         5284          197         >19.8
w1                4879         5079          197         >19.5
m2                4674         4874          197         >19.7
w2                5701         5726           25         >18.7

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.13 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB180715A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22968
SUBJECT: GRB 180715A: Gemini imaging upper limits
DATE:    18/07/19 22:55:09 GMT
FROM:    Wen-fai Fong at Northwestern U  <wfong@northwestern.edu>

W. Fong (Northwestern Univ.), A. J. Levan (U. Warwick), R. Chornock (Ohio Univ.) report on behalf of a larger collaboration:

"We observed the location of the short-duration GRB 180715A (Ukwatta et al., GCN 22947) with the twin Gemini-North and Gemini-South 8-meter telescopes located on Mauna Kea, Hawaii and Cerro Pachon, Chile, respectively. We used the pair of Gemini Multi-Object Spectrographs (GMOS) to obtain r-band imaging at mid-times of 5.9 hr, 13.0 hr and 1.2 days post-burst, spanning 2018 Jul 16-Jul 17 UT. Our observational coverage of the refined Swift/BAT position (90% containment; Ukwatta et al., GCN 22951) as well as the uncatalogued Swift/XRT sources (Kennea et al., GCN 22953) is as follows:

5.9 hr: ~70% of BAT position, XRT S7 and S11
13.0 hr: 100% of BAT position, XRT S8
1.2 days: 100% of BAT position, XRT S8

We identify optical sources in and around each of these 3 XRT sources (90% containment; Kennea et al., GCN 22953) in our imaging; however, all sources are clearly visible in archival PS1 or SDSS imaging and have measured magnitudes within +/- 0.3 mag of known values. Furthermore, we do not detect any uncatalogued optical sources in or around these 3 XRT sources to 3-sigma limits of r>23.6 AB mag (S7 and S11 at 5.9 hr) and r>25.2 AB mag (S8 at 13.0 hr). The photometry is calibrated to SDSS DR12 and is not corrected for Galactic extinction in the direction of the burst.

Finally, we perform image subtraction between the observations at 13.0 hr and 1.2 days, which each provide full coverage of the refined BAT position (90% containment). We note that there is significant contamination from the 8th mag star that affects ~20% of the BAT position in the subtraction. For the remaining, uncontaminated region, we place a 3-sigma limit of r>24 AB mag on the optical afterglow of GRB 180715A at 13.0 hr after the burst.

We thank the Gemini-North and Gemini-South queue observers and staff for their rapid assistance with these observations."


GRB_name: GRB180715B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22969
SUBJECT: GRB180715B: Zwicky Transient Facility Follow-Up of a Fermi Short GRB (Trigger 553369644)
DATE:    18/07/20 01:53:36 GMT
FROM:    S. Bradley Cenko at NASA/GSFC  <brad.cenko@nasa.gov>

S. Bradley Cenko (NASA GSFC), Michael W. Coughlin (Caltech), Shaon Ghosh (UWM), Tomas Ahumada (UMD), Virginia Cunningham (UMD), Pradip Gatkine (UMD), Eric C. Bellm (UW), Mansi M. Kasliwal (Caltech), Leo P. Singer (NASA GSFC), V. Zach Golkhou (UW), and Lin Yan (Caltech) on behalf of the ZTF and GROWTH collaborations and the KPED team

We observed the localization region of the short GRB 180715B (trigger 553369644) detected by the Gamma-Ray Burst Monitor (GBM) on the Fermi satellite with the Palomar 48-inch telescope equipped with the 47 square degree Zwicky Transient Facility (ZTF) camera. We obtained a series of r- and g-band images covering 254.31 square degrees beginning at 04:18 UT on 2018 July 16 (10:22 hours after the burst trigger time), corresponding to ~ 36% of the probability enclosed in the localization region.  

The images were processed through the ZTF reduction and image subtraction pipelines at IPAC to search for potential counterparts. 45 high-significance transient and variable candidates were identified by our pipeline in the area observed, most (31) of which had previous detections with ZTF in the days and weeks prior to the GRB trigger time (e.g., supernovae, active galactic nuclei). The 14 transients discovered the night of July 16 are listed in the table below. 

 ZTF ID           RA           DEC     discovery magnitude    last non-detection    
----------------------------------------------------------------------------------
ZTF18aamwzlv  13:06:44.59  +68:59:52.9  2018 Jul 16 g=21.26  2018 Jul 08 g>20.34    
ZTF18abhbevp  14:21:00.83  +72:11:43.8  2018 Jul 16 g=20.64  2018 Jul 07 g>20.08  
ZTF18abhbpkm  16:02:36.78  +70:47:05.1  2018 Jul 16 g=21.24  2018 Jul 13 g>20.52   
ZTF18abhhjyd  13:02:32.07  +75:16:49.4  2018 Jul 16 g=21.24  2018 Jul 05 g>20.56  
ZTF18abhbgan  15:43:18.86  +72:05:24.8  2018 Jul 16 g=21.22  2018 Jul 13 g>20.17 
ZTF18abhbfoi  13:24:34.01  +70:56:47.5  2018 Jul 16 g=21.12  2018 Jul 08 g>20.55   
ZTF18abhbcjy  14:20:50.39  +73:25:40.5  2018 Jul 16 g=20.65  2018 Jul 17 g>20.51   
ZTF18abhaogg  13:42:45.47  +74:19:38.3  2018 Jul 16 r=20.40  2018 Jul 05 r>20.35   
ZTF18abhbamj  15:26:58.78  +72:02:17.8  2018 Jul 16 g=21.22  2018 Jul 13 g>20.01   
ZTF18abhawjn  13:31:27.33  +66:46:45.4  2018 Jul 16 r=21.19  2018 Jul 08 r>20.31   
ZTF18abharzk  13:41:09.05  +70:43:06.8  2018 Jul 16 r=21.30  2018 Jul 08 r>20.28   
ZTF18abhbckn  12:49:53.85  +73:02:00.5  2018 Jul 16 r=20.93  2018 Jul 08 r>19.96   
ZTF18abhbfqf  13:16:00.24  +69:37:24.1  2018 Jul 16 g=19.59  2018 Jul 08 g>20.50 
ZTF18aauhpyb  13:21:45.49  +70:55:59.8  2018 Jul 16 r=18.99  2018 Jul 08 r>20.28 

The median 5-sigma upper limit for an isolated point source in our images was r > 21.4 and g > 21.6 mag for the observations made on July 16 and r > 21.4 and g > 21.3 mag for the observations made on July 17.

We obtained follow-up spectroscopy of ZTF18aauhpyb with the Spectral Energy Distribution Machine (SEDM; Blagorodnova et al., 2018, PASP) on the Palomar 60 inch telescope on the night of July 18.  The spectrum displays a blue continuum with emission lines from Balmer H at a redshift of 0.  We thus classify the source as a variable star.

We also obtained follow-up spectroscopy of ZTF18abhbfqf with the Double Spectrograph (DBSP) on the 200 inch Hale Telescope at Palomar Observatory on the night of July 17.  Cross-correlation with template spectra using the Superfit package (Howell et al., 2005, ApJ) indicates the source is a type Ia supernova before maximum light at a redshift of z = 0.110 (from host galaxy features).

Further observations are planned.

ZTF is a project led by PI S. R. Kulkarni at Caltech (see ATEL #11266), and includes IPAC; WIS, Israel; OKC, Sweden; JSI/UMd, USA; UW, USA; DESY, Germany; NRC, Taiwan; UW Milwaukee, USA and LANL USA. ZTF acknowledges the generous support of the NSF under AST MSIP Grant No 1440341. Alert distribution service provided by DIRAC@UW. Alert filtering is being undertaken by the GROWTH marshal system, supported by NSF PIRE grant 1545949.
 


GRB_name: GRB180720A
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22970
SUBJECT: AGILE/MCAL detection of GRB 180720A
DATE:    18/07/20 07:09:02 GMT
FROM:    Alessandro Ursi at INAF/IAPS  <alessandro.ursi@gmail.com>

AGILE/MCAL detection of GRB 180720A

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

The AGILE Mini-CALorimeter (MCAL) detected a burst at T0 = 2018-07-20
05:06:03.29 +/- 0.01 s (UTC), lasting about ~ 3.6 s in the 0.4-100 MeV
energy range. The light curve is composed of a single smooth peak and
released a total of ~3000 counts at E> 400 keV in the detector, above an
average background rate of 20 counts / 32 ms.

Further analysis is still in progress.

The AGILE-MCAL detector has a full solid angle acceptance, and is
operational in the range 0.4 - 100 MeV.


GRB_name: GRB180718B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22971
SUBJECT: GRB 180718B: MASTER optical observation 
DATE:    18/07/20 12:48:11 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

E. Gorbovskoy, V. Lipunov, V.Kornilov,  N.Tiurina, 
A.Kuznetsov, V.Chazov, I. Gorbunov, D. Vlasenko, D.Zimnukhov, D.Kuvshinov, 
P.Balanutsa, V.Vladimirov
Lomonosov Moscow State University,SAI

D. Buckley,
South African Astronomical Observatory (SAAO)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias (IAC)

A. Tlatov, V.Senik, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

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

H.Levato,
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University (ISU)

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


MASTER-OAFA robotic telescope (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  GRB180718.76 36087 sec after notice time and 36087 sec after 
trigger time at 2018-07-19 04:19:52 UT. On our combined images (1800 s), 
started 41401 sec after tigger time at 2018-07-19 05:48:25 UT, we 
not found  optical transient within LAT error-box (ra=44.6792 dec=-31.5 
r=1)  brighter then 20.4.


The observations made on zenit distance = 74 degrees, galaxy latitude b = 
-62 degree. The moon (44 % bright part) below the horizon (The altitude of 
the Moon is  -20 degree ).
The sun  altitude  is -71.7 degree.
The object can be observed till sunrise at 2018-07-19 11:33:26 .

The message may be cited.


GRB_name: GRB180718A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22972
SUBJECT: GRB 180718A: MASTER optical observation 
DATE:    18/07/20 13:00:27 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

D. Vlasenko, N.Tiurina,  E. Gorbovskoy, V. Lipunov, V.Kornilov, 
A.Kuznetsov, V.Chazov, I.  Gorbunov, D.Zimnukhov, D.Kuvshinov, 
P.Balanutsa, V.Vladimirov
Lomonosov Moscow State University,SAI

D. Buckley,
South African Astronomical Observatory (SAAO)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias (IAC)

A. Tlatov, V.Senik, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

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

H.Levato,
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University (ISU)

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



MASTER Global Robotic Net  ( Lipunov et al., 2010, Advances in Astronomy, 
vol. 2010, 30L) inspected  GRB180718A  (Svinkin et al. GCN22959 ;
Fermi trigger 553571869  at 2018-07-18 01:57:44.60 UT , Hamburg  et al. 
GCN22960; Swift BAT position RA,Dec2000= 22h 24m 04.6s +02d 47' 23.3" 
(Svinkin et  al GCN22959; Evans et al. GCN22963)

MASTER-Kislovodsk robotic telescope (MASTER-Net: 
http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, 
vol. 2010, 30L) located in Russia (Pulkovo Solar Station) was pointed to 
the GRB180718A (D. Svinkin et al., GCN Circ #22959) 60867 sec after 
trigger time at 2018-07-18 18:52:12 UT . On our first (180s exposure)  set 
we  do not found  optical transients within Swift error-box (ra=336.019 
dec=2.790 r=0.05)  brighter then 18.5.

The observations made on zenit distance = 13.51 degrees, galaxy latitude b 
= -43.86 degree.
The moon (39 % bright part) is 15 degrees above the horizon. The distance 
between  moon and  object is 142
The sun  altitude  is -17.5 degree.
The errorbox observed 2 nights till 2018-07-19 22:23:00

MASTER-Tavrida robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
Russia (SAI Crimea astronomical station) was pointed to the GRB180718A (D. 
Svinkin et al., GCN Circ #22959) 63704 sec after trigger time at 
2018-07-18 19:39:29 UT . On our first (180s exposure)  set we  do not 
found  optical transients within Swift error-box (ra=336.019 dec=2.790 
r=0.05)  brighter then 18.6.

The observations made on zenit distance = 15.68 degrees, galaxy latitude b 
= -43.86 degree.
The moon (39 % bright part) is 13 degrees above the horizon. The distance 
between  moon and  object is 142
The sun  altitude  is -18 degree.
The errorbox observed 2 nights till 2018-07-19 21:25:48

MASTER-IAC robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
Spain (IAC Teide Observatory) was pointed to the GRB180718A (D. Svinkin et 
al., GCN Circ #22959) 161995 sec after trigger time at 2018-07-19 22:57:40 
UT . On our first (180s exposure)  set we  do not found  optical 
transients within Swift error-box (ra=336.019 dec=2.790 r=0.05)  brighter 
then 17.5.

The observations made on zenit distance = 18.52 degrees, galaxy latitude b 
= -43.86 degree.
The moon (39 % bright part) is 25 degrees above the horizon. The distance 
between  moon and  object is 128
The sun  altitude  is -11.80 degree.
The errorbox observed till 2018-07-19 23:53:58

The visibility GRB error box (coord: 336.019 2.790  error_box: 0.05)
at trigger time at different MASTER sites:

obj:  43.32 sun: -3.21 - Tavrida (Crimea, Russia)
obj:  53.60 sun: -39.34 - IAC, Teide, (Tenerife, Spain)
obj:  53.56 sun: -45.24 - SAAO (Sutherland, SA)
obj:  40.32 sun:  1.49 - Kislovodsk (Russia)
obj:  23.50 sun:  16.36 -  Ural(Kourovka, Russia)
obj:  0.76  sun:  41.53 -  Tunka (near Baykal Lake, Russia)
obj: -14.45 sun:  55.06 -  Amur(Blagoveschensk)
obj:  6.93  sun: -51.86 -   OAFA (Argentina)

The message may be cited.


GRB_name: GRB180720B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22973
SUBJECT: GRB 180720B: Swift detection of a burst
DATE:    18/07/20 14:34:56 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

M. H. Siegel (PSU), D. N. Burrows (PSU), A. Deich (PSU),
J.D. Gropp (PSU), J. A. Kennea (PSU), S. J. LaPorte (PSU),
A. Y. Lien (GSFC/UMBC), M. J. Moss (George Washington University),
K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (PSU) and
A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 14:21:44 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180720B (trigger=848890).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 0.530, -2.933 which is 
   RA(J2000) = 00h 02m 07s
   Dec(J2000) = -02d 56' 00"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multi-peaked
structure with a duration of about 150 sec.  The peak count rate
was ~50000 counts/sec (15-350 keV), at ~11 sec after the trigger. 

The XRT began observing the field at 14:23:11.0 UT, 86.5 seconds after
the BAT trigger. XRT found a bright, flaring and fading uncatalogued 
X-ray source located at RA, Dec 0.5279, -2.9170 which is equivalent to:
   RA(J2000)  = +00h 02m 6.70s
   Dec(J2000) = -02d 55' 01.2"
with an uncertainty of 5.0 arcseconds (radius, 90% containment). This
location is 58 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy. 

The initial flux in the 0.1 s image was 6.59e-08 erg cm^-2 s^-1 (0.2-10
keV). 

No UVOT data is available yet. 

Burst Advocate for this burst is M. H. Siegel (siegel AT swift.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/too.html.)

[GCN OPS NOTE(21jul18):  In response to GCN Circular 22975, this 
archived copy of 22973 has been modified with the correct GRB maining
"A" --> "B".]


GRB_name: GRB180720A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22974
SUBJECT: GRB 180720A: Fermi GBM observation
DATE:    18/07/20 14:39:48 GMT
FROM:    Elisabetta Bissaldi at INFN,Bari  <elisabetta.bissaldi@ba.infn.it>

E. Bissaldi (Politecnico & INFN Bari)
reports on behalf of the Fermi GBM Team:


"At 05:06:02.06 UT on 20 July 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180720A (trigger 553755967 / 180720213),
which was also detected by the AGILE/MCAL (Ursi et al. 2018, GCN 22970).

The on-ground calculated location, using the GBM trigger data, is

RA, Dec = 127.0, -0.4 (J2000 degrees),

with an uncertainty of 1 degree (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 74 degrees.

The GBM light curve consists of single FRED-like peak
with a duration (T90) of about 9 s (50-300 keV).
The time-averaged spectrum from T0 to T0+10 s is
best fit by a Band function with Epeak = 260 +/- 15 keV,
alpha = -1.08 +/- 0.02 and beta = -2.13 +/- 0.06.

The event fluence (10-1000 keV) in this time interval is
(2.563 +/- 0.026)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+1.3 s in the 10-1000 keV band
is 36.5 +/- 0.5 ph/s/cm^2.


The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB180720B
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22975
SUBJECT: Correction: Swift trigger #848890 is GRB 180720B (not GRB 180720A)
DATE:    18/07/20 14:48:26 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

M. H. Siegel (PSU), D. N. Burrows (PSU), A. Deich (PSU),
J.D. Gropp (PSU), J. A. Kennea (PSU), S. J. LaPorte (PSU),
A. Y. Lien (GSFC/UMBC), M. J. Moss (George Washington University),
K. L. Page (U Leicester), D. M. Palmer (LANL), B. Sbarufatti (PSU) and
A. Tohuvavohu (PSU) report on behalf of the Neil Gehrels Swift
Observatory Team:

The GRB name in GCN Circ. #22973 should be GRB 180720B because of 
an earlier detection of GRB 180720A from AGILE/MCAL (GCN Circ. #22970).

We apologize for the mistake and any confusion caused by this.


GRB_name: GRB180720B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22976
SUBJECT: GRB 180720B: LCO Haleakala possible bright optical candidate
DATE:    18/07/20 15:30:47 GMT
FROM:    Renato Martone at Universita' di Ferrara  <mrtrnt@unife.it>

R. Martone, C. Guidorzi (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell (U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU), A. Cucchiara, D. Morris (U. of Virgin Islands) on behalf of a large collaboration report:

The LCO 2-m unit at Haleakala Observatory (Hawaii) began observing Swift GRB180720B (Siegel et al. GCN 22973)  on July 20, 14:33:34 UT (11.8 minutes after the GRB trigger time) with the SDSS i' filter. On the border of the Swift-XRT error circle, we detect a 13-mag uncatalogued object at the following position:

RA(J2000)= +00:02:06.87
DEC(J2000)= -02:55:05.2

with an error radius of ~1â€  as calibrated against nearby SDSS stars.


GRB_name: GRB180720B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22977
SUBJECT: GRB 180720B: Kanata 1.5m optical/NIR observation
DATE:    18/07/20 16:21:08 GMT
FROM:    Koji Kawabata at HASC,Hiroshima U  <kawabtkj@hiroshima-u.ac.jp>

M. Sasada, T. Nakaoka, M. Kawabata, N. Uchida, Y. Yamazaki,
K. S. Kawabata (Hiroshima Univ.) report on behalf of Kanata team:

We performed optical and NIR imaging polarimetry to the field of the
GRB 180720B (Siegel et al. GCN 22973; Martone et al. GCN 22976) from
2018-07-20 14:22:57 UT (73 seconds after the trigger) with HOWPol 
and HONIR attached to the 1.5-m Kanata telescope at Higashi-Hiroshima
Observatory, Japan. We detected a bright optical counterpart of the 
GRB within the the Swift-XRT error circle of the X-ray afterglow. The
magnitude of the optical counterpart was R~9.4 mag in our first frame 
taken with 30 second exposure and then smoothly declined. Further
analysis is ongoing.


GRB_name: GRB180715A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22978
SUBJECT: GRB 180715A: MASTER optical observation 
DATE:    18/07/20 18:09:52 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

D. Vlasenko, N.Tiurina,  E. Gorbovskoy, V. Lipunov, V.Kornilov, A.Kuznetsov, 
V.Chazov, I.  Gorbunov, D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov
Lomonosov Moscow State University,SAI
4
A. Tlatov, V.Senik, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

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

H.Levato,
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University (ISU)

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

D. Buckley,
South African Astronomical Observatory (SAAO)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias (IAC)


MASTER-Tavrida robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
Russia (SAI Crimea astronomical station) was pointed to the GRB180715A 
(Ukwatta et al., GCN Circ #22947) 96 sec after trigger time at 2018-07-15 
18:08:41 UT as sun altitude was -6.95 dec first image was at 2018-07-15 
18:30:37.  On our first (180s exposure)  set we do not found  optical 
transients within Swift error-box (ra=235.069 dec=-0.925 r=0.05)  brighter 
then 20.7.

The observations made on zenit distance = 44.16 degrees, galaxy latitude b 
= 40,1 degree.
The moon (10 % bright part) is 8 degrees above the horizon. The distance 
between  moon and  object is 82
The sun  altitude  is -9.85 degree.
The object can be observed till 2018-07-15 21:36:28

MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
South Africa (South African Astronomical observatory) was pointed to the 
GRB180715A (Ukwatta et al., GCN Circ #22947) 495 sec after trigger time at 
2018-07-15 18:15:20 UT . On our first (100s exposure)  set we  do not 
found  optical transients within Swift error-box (ra=235.069 dec=-0.925 
r=0.05)  brighter then 20.8.

The observations made on zenit distance = 57.43 degrees, galaxy latitude b 
= 40.1 degree.
The moon (10 % bright part) is 6.5 degrees above the horizon. The distance 
between  moon and  object is 83
The sun  altitude  is -28.83 degree.
The object can be observed till 2018-07-15 22:48:22.

The visibility GRB error box (coord: 235.069 -0.925  error_box: 0.05) at 
trigger time at different MASTER sites:

obj:  44.19 sun: -6.73 - Tavrida (Crimea, Russia)
obj:  36.94 sun:  23.52 - IAC, Teide (Tenerife,Spain)
obj:  57.43 sun: -28.83 - SAAO (Sutherland, SA)
obj:  43.89 sun: -11.87 - Kislovodsk (Russia)
obj:  27.30 sun: -7.55 - Ural (Kourovka, Russia)
obj:  9.49  sun: -15.74 - Tunka (near Baykal Lake, Russia)
obj: -5.64  sun: -10.73 - Amur(Blagoveschensk)
obj: -7.22  sun:  32.97 - OAFA (Argentina)

The message may be cited.


GRB_name: GRB180720B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22979
SUBJECT: GRB 180720B : TSHAO optical observations
DATE:    18/07/20 21:36:57 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

I. Reva (FAPHI), A. Pozanenko (IKI), A. Volnova (IKI),  E. Mazaeva (IKI), 
A. Kusakin (FAPHI),  M. Krugov (FAPHI) report on behalf of larger GRB
follow-up collaboration:

We observed the field of GRB 180720B (Siegel  et al., GCN 22973)  with 
Zeiss-1000 telescope of Tien Shan Astronomical Observatory starting on July 
20  (UT) 19:46:17. We obtained several images in R and B-filters.  The 
optical afterglow (Martone et al. GCN 22976;  Sasadaet al., GCN 22977)  is 
clearly detected in both filters.  Preliminary photometry  of the afterglow 
at  (UT, mid time) 19:59 is R =17.1 +/- 0.1. The photometry is based on 
nearby USNO-B1.0 (R2) stars.


GRB_name: GRB180720B
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22980
SUBJECT: GRB 180720B : Fermi-LAT detection
DATE:    18/07/20 22:28:56 GMT
FROM:    Elisabetta Bissaldi at INFN,Bari  <elisabetta.bissaldi@ba.infn.it>

E. Bissaldi (Politecnico & INFN Bari) and J. L. Racusin (NASA/GSFC)
report on behalf of the Fermi-LAT team:


"At 14:21:44.55 UT on July 20, 2018, Fermi-LAT detected
high-energy emission from GRB 180720B, which was also
detected by Swift (Siegel et al. 2018, GCN 22973)
and by Fermi-GBM (trigger 553789304 / 180720598).

The best LAT on-ground location is found to be

RA, Dec = 0.58, -2.95 (J2000)

with an error radius of 0.11 deg (90 % containment, statistical error only).
This was 50 deg from the LAT boresight at the time of the trigger.

The data from the Fermi-LAT show a significant increase
in the event rate that is spatially and temporally correlated
with the trigger with very high significance.
The highest-energy photon is a 5 GeV event which is
observed 137 seconds after the GBM trigger.
Given that GRB 180720B is detected by both Swift and Fermi,
and it is very bright in the LAT, we encourage follow-up observations.

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: GRB180720B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22981
SUBJECT: GRB 180720B: Fermi GBM observation
DATE:    18/07/20 22:50:18 GMT
FROM:    Oliver J Roberts at USRA/NASA  <oliver.roberts@nasa.gov>

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

"At 14:21:39.65 UT on 20 July 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180720B (trigger 553789304 / 180720598),
which was also detected by Swift (Siegel et al. 2018, GCN 22973/22975) 
and the LAT (Bissaldi et al., GCN 22980). The GBM on-ground location is 
consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time using the
Swift-XRT position is 50 degrees.

The GBM light curve consists of a very bright, FRED-like peak with 
numerous overlapping pulses with a duration (T90) of 49 s (50-300 keV).
The time-averaged spectrum from T0 to T0+55 s is best fit by a Band 
function with Epeak = 631 +/- 10 keV, alpha = -1.11 +/- 0.01 and 
beta = -2.30 +/- 0.03.

The event fluence (10-1000 keV) over the T90 interval is 
(2.985 +/- 0.001)E-04 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+4.4 s in the 10-1000 keV band is 125 +/- 1 ph/s/cm^2.


The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB180720C
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22982
SUBJECT: GRB 180720C: Swift detection of a burst or possible Galactic Transient
DATE:    18/07/20 22:54:24 GMT
FROM:    Boris Sbarufatti at PSU  <bxs60@psu.edu>

S. J. LaPorte (PSU), P. A. Evans (U Leicester), J.D. Gropp (PSU),
J. A. Kennea (PSU), A. Y. Lien (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), M. J. Moss (George Washington University),
B. Sbarufatti (PSU) and A. Tohuvavohu (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 22:23:57 UT, the Swift Burst Alert Telescope (BAT) triggered and
located a possible GRB 180720C or Galactic transient (trigger=848932). 
Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 265.623, -26.584 which is 
   RA(J2000) = 17h 42m 30s
   Dec(J2000) = -26d 35' 01"
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 30 sec.  The peak count rate
was ~2000 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 22:25:34.8 UT, 97.2 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source located at RA, Dec 265.63486, -26.63041 which is
equivalent to:
   RA(J2000)  = 17h 42m 32.37s
   Dec(J2000) = -26d 37' 49.5"
with an uncertainty of 5.7 arcseconds (radius, 90% containment). This
location is 171 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
http://www.swift.ac.uk/sper.  We cannot determine whether the source is
fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (6.76 x
10^21 cm^-2, Willingale et al. 2013), with an excess column of 2.7
(+3.01/-2.29) x 10^22 cm^-2 (90% confidence). 

We note that the detected source is at the edge of the reduced field of view available with the promptly down linked data. Because of that the accuracy of the position could be lower than stated. 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 100 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. Because of the density of
catalogued stars, further analysis is required to report an upper limit for any
afterglow in the region. No correction has been made for the large, but
uncertain, extinction expected. 

While the BAT and XRT data are consistent with a GRB, because of the
proximity to the Galactic Center, at present we cannot rule out a
Galactic transient nature for the source. 

Burst Advocate for this burst is S. J. LaPorte (extragsam 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/too.html.)


GRB_name: GRB180720B
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22983
SUBJECT: GRB 180720B: MITSuME Akeno optical observations
DATE:    18/07/21 02:16:27 GMT
FROM:    Ryosuke Itoh at Tokyo Institute of Tech.  <itoh@hp.phys.titech.ac.jp>

R. Itoh, K. L. Murata, Y. Tachibana, S. Harita, K. Morita,
K. Shiraishi, K. Iida, M. Oeda, R. Adachi, S. Niwano,
Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We observed the optical counterpart of GRB 180720B
(Siegel et al., GCN 22973)
with the optical three color (g', Rc, and Ic) CCD cameras attached to
the MITSuME 50cm telescope of Akeno Observatory, Yamanashi, Japan.

The observation started on 2018-07-20 18:08:46 UT, (~3.8 hours after
the burst). We detected the previously reported afterglow
(Martone et al., GCN 22976, Sasada et al., GCN 22977, Reva et al., GCN 22979)
in the g', Rc and Ic band.

The photometric results of the OT are listed below.
We used UCAC-4 catalog for flux calibration.

#T0+[hour]  MID-UT    T-EXP[sec] g'   Rc   Ic
-------------------------------------------------------------------
3.8    18:14:30   540  16.53+/-0.06  16.67+/-0.06 16.25+/- 0.08
-------------------------------------------------------------------
T0+ : Elapsed time after the burst [hour]
T-EXP: Total Exposure time [sec]


GRB_name: GRB180720B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22984
SUBJECT: GRB 180720B: Swift-XRT refined Analysis
DATE:    18/07/21 02:17:13 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

K.L. Page (U. Leicester), A.P. Beardmore (U. Leicester), V. D'Elia
(ASDC), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), A. Tohuvavohu
(PSU), S. J. LaPorte (PSU), J.A. Kennea (PSU), P.A. Evans (U.
Leicester) and M.H. Siegel report on behalf of the Swift-XRT team:

We have analysed 7.2 ks of XRT data for GRB 180720B (Siegel et al. GCN
Circ. 22973), from 90 s to 19.4 ks after the  BAT trigger. The data
comprise 3.3 ks in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The refined XRT position is RA, Dec =
0.5286, -2.9189 which is equivalent to:

RA (J2000): 00 02 06.86
Dec(J2000): -02 55 08.1

with an uncertainty of 3.5 arcsec (radius, 90% confidence).

The late-time light curve (from T0+5.6 ks) can be modelled with an
initial power-law decay with an index of alpha=1.18 (+0.16, -0.28),
followed by a break at T+7030 s to an alpha of -0.17 (+0.26, -1.33).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.770 (+/-0.011). The
best-fitting absorption column is  1.42 (+/-0.04) x 10^21 cm^-2, in
excess of the Galactic value of 3.9 x 10^20 cm^-2 (Willingale et al.
2013). The PC mode spectrum has a photon index of 1.85 (+/-0.07) and a
best-fitting absorption column of 1.75 (+0.23, -0.22) x 10^21 cm^-2.
The counts to observed (unabsorbed) 0.3-10 keV flux conversion factor
deduced from this spectrum  is 3.8 x 10^-11 (4.9 x 10^-11) erg cm^-2
count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.75 (+0.23, -0.22) x 10^21 cm^-2
Galactic foreground: 3.9 x 10^20 cm^-2
Excess significance: 10.1 sigma
Photon index:      1.85 (+/-0.07)

If the light curve continues to decay with a power-law decay index of
-0.17, the count rate at T+24 hours will be 21 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 8.4 x
10^-10 (1.1 x 10^-9) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00848890.

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

[GCN OPS NOTE(21jul18):  In response to GCN Circular 22986, this
archived copy of 22984 has been modified with the correct GRB maining
"A" --> "B".]


GRB_name: GRB180720B
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22985
SUBJECT: GRB 180720B: OSN detection, fading slower?
DATE:    18/07/21 02:51:06 GMT
FROM:    Alexander Kann at IAA-CSIC  <kann@iaa.es>

D. A. Kann, L. Izzo (both HETH/IAA-CSIC), V. Casanova (IAA-CSIC), and A. de
Ugarte Postigo (HETH-IAA/CSIC and DARK/NBI) report on behalf of HETH:

We observed the position of the extremely bright GRB 180720B (Swift-BAT 
detection: Siegel et al., GCN #22973, GCN #22975; Fermi-LAT detection: 
Bissaldi and Racusin, GCN #22980; Fermi-GBM detection: Roberts et al., 
GCN #22981) with the T90 telescope of the Observatorio Sierra Nevada 
(OSN) near Granada, Spain.

The optical afterglow (Martone et al., GCN #22976; Sasada et al., GCN 
#22977; Reva et al., GCN #22979; Itoh et al., GCN #22983) is clearly 
detected in single 180 s images. For an Rc image at mid-time 0.455188 
days after the INTEGRAL SPI/ACS trigger (14:21:40 UT), we derive Rc = 
17.53 +/- 0.03 mag.

We note that this is only ~0.4 mag fainter than the value found by Reva 
et al. at 0.23 days after the GRB, indicating the decay may have slowed 
down. This feature also seems to be seen in the XRT light curve (Page et 
al., GCN #22984).

Further observations, even with smaller telescopes, are strongly 
encouraged.

Magnitudes were obtained against SDSS standard stars transformed 
following the equations of Lupton (2005).

[GCN OPS NOTE(21jul18): Due to a processing problem with some
in-line UTF formatting characters, the "slower?" was deleted
from the SUBJECT-line in the distributed circulars.  It has been
replaced in these archived copies.]

[GCN OPS NOTE(21jul18): Per author's request, A. de U.P. was added
to the author list.]


GRB_name: GRB180720B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22986
SUBJECT: GCN 22984 was for GRB 180720B
DATE:    18/07/21 02:59:07 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 :

The XRT refined analysis reported in GCN Circ. 22984 was the analysis of GRB 180720B, not A as reported in the circular. Apologies for the confusion.


GRB_name: GRB180720C
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22987
SUBJECT: GRB 180720C: Enhanced Swift-XRT position
DATE:    18/07/21 03:44:53 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 2824 s of XRT Photon Counting mode data and 7 UVOT
images for GRB 180720C, 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 = 265.63557, -26.62903 which is equivalent
to:

RA (J2000): 17h 42m 32.54s
Dec (J2000): -26d 37' 44.5"

with an uncertainty of 1.9 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: GRB180720B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22988
SUBJECT: GRB 180720B: LCO optical afterglow observations
DATE:    18/07/21 04:59:42 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

Nicolas Crouzet (IAC) and Daniele B. Malesani (DAWN/NBI and DARK/NBI) 
report:

We observed the optical afterglow of GRB 180720B (Siegel et al., GCN 
22973; Martone et al., GCN 22976) using the 0.4-m telescope located at 
the Teide Observatory, part of the Las Cumbres Observatory (LCO) 
telescope network.

A single 600-s exposure in the SDSS r band was obtained with mean time 
July 21.094 UT (0.495 days after the GRB). The PSF of the image is not 
optimal, being double-peaked.

Aperture photometry, compared to nearby stars from the Pan-STARRS 
catalog, provides for the afterglow a preliminary magnitude r = 17.85 +- 
0.10 AB.


GRB_name: GRB180706A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22989
SUBJECT: GRB 180706A: OSN detection
DATE:    18/07/21 05:26:20 GMT
FROM:    Alexander Kann at IAA-CSIC  <kann@iaa.es>

D. A. Kann, L. Izzo (both HETH/IAA-CSIC) and A. Sota (IAA-CSIC) report 
on behalf of HETH:

We observed the position of the Swift GRB 180706A (Stamatikos et al., 
GCN #22909) with the T150 telescope of the Observatorio Sierra Nevada 
(OSN) near Granada, Spain.

We obtained 6 x 300 s Ic images (mean time after trigger 0.546615 days) 
and further 5 x 300 s Ic images a night later (mean time after trigger 
1.57231 days).

The afterglow (Stamatikos et al., GCN #22909; Watson et al., GCN #22910; 
Oates et al., GCN #22922; Volnova et al., GCN #22923) is clearly 
detected in the first night, and we derive Ic = 20.56 +/- 0.06 mag. It 
is not detected anymore in the second night to a limit of Ic > 22.5. The 
detection magnitude is in good agreement with the earlier measurement of 
Volnova et al. when typical Rc-Ic colors of GRBs are taken into account.

The lead author is sorry for the long vacation this data took.


GRB_name: GRB180720C
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22990
SUBJECT: GRB 180720C: Fermi GBM observation
DATE:    18/07/21 05:39:40 GMT
FROM:    Oliver J Roberts at USRA/NASA  <oliver.roberts@nasa.gov>

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

"At 22:23:53.15 UT on 20 July 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180720C (trigger 553818238 / 180720933),
which was also detected by Swift (S.J. LaPorte et al. 2018, GCN 22982).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time using 
the Swift-XRT position is 111 degrees.

The GBM light curve consists of broad, single peak with a 
duration (T90) of about 23 s (50-300 keV). The time-averaged spectrum 
from T0-6.1 to T0+17.4 s is adequately fit by a power law function 
with an exponential high-energy cutoff. The power law index is 
-1.12 +/- 0.08 and the cutoff energy, parameterized as Epeak, 
is 583 +/- 161 keV.

The event fluence (10-1000 keV) over this time interval is
(2.83 +/- 0.05)E-06 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+4.3 s in the 10-1000 keV band is 2.8 +/- 0.3 ph/s/cm^2.


The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB180720C
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22991
SUBJECT: GRB 180720C: LT observations
DATE:    18/07/21 08:22:42 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi, R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell 
(U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU) on behalf of a 
large collaboration report:

The 2-m robotic Liverpool Telescope automatically began observing Swift 
GRB 180720C (LaPorte et al. GCN 22982) on July 20, 22:28:18 UT (261 
seconds after the GRB trigger time) with the RINGO3 polarimeter and the 
IO:O camera in the SDSS-R filter. Within the enhanced Swift-XRT error 
circle (Evans et al. GCN 22987) we do not find any uncatalogued object 
down to r'>20.4 mag at a mid time of 47 minutes post GRB with a 3x10s 
exposure, as calibrated against nearby Pan-STARRS objects.


GRB_name: GRB180720C
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22992
SUBJECT: GRB 180720C: Swift/UVOT Upper Limits
DATE:    18/07/21 08:35:26 GMT
FROM:    Samantha Oates at MSSL  <sro@mssl.ucl.ac.uk>

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

The Swift/UVOT began settled observations of the field of GRB 180720C
100 s after the BAT trigger (LaPorte et al., GCN Circ. 22982).
No optical afterglow consistent with the XRT position (Evans et al., GCN
Circ. 22987) 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           >20.3
white              100         5490         541           >21.0    
u (FC)             312         425          111           >19.2
u                  312         11199       1193           >20.6
v                  4263        5901         393           >19.1
b                  3646        11902       1072           >20.8
uvw1               4674        10285       1133           >20.3
uvm2               4469        6106         393           >19.7
uvw2               4058        5696         393           >19.8

The magnitudes in the table are not corrected for the Galactic extinction
due to the significant reddening of E(B-V) = 2.11 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB180720B
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22993
SUBJECT: GRB 180720B: MAXI/GSC detection
DATE:    18/07/21 11:19:21 GMT
FROM:    H. Negoro at Nihon U.  <negoro@phys.cst.nihon-u.ac.jp>

H. Negoro (Nihon U.), A. Tanimoto (Kyoto U.), 
M. Nakajima, W. Maruyama, A. Sakamaki (Nihon U.), 
T. Mihara, S. Nakahira, F. Yatabe, Y. Takao, M. Matsuoka (RIKEN), 
N. Kawai, M. Sugizaki, Y. Tachibana, K. Morita (Tokyo Tech), 
T. Sakamoto, M. Serino, S. Sugita, Y. Kawakubo, T. Hashimoto, A. Yoshida (AGU), 
S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N. Isobe, R. Shimomukai (JAXA), 
Y. Ueda, T. Morita, S. Yamada (Kyoto U.), Y. Tsuboi, W. Iwakiri, R. Sasaki, 
H. Kawai, T. Sato (Chuo U.), H. Tsunemi, T. Yoneyama (Osaka U.), 
M. Yamauchi, K. Hidaka, S. Iwahori (Miyazaki U.), T. Kawamuro (NAOJ), 
K. Yamaoka (Nagoya U.), M. Shidatsu (Ehime U.) 
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered on GRB 180720B (Siegel et al., GCN 22973/20975;
Bissaldi et al., GCN 22980; Roberts et al., GCN 22981) at 14:28:15 UT on 2018 July 20, 
396 sec after the Fermi/GRB trigger.
Assuming that the source flux was constant over the transit, we obtain the source position at
(R.A., Dec) = (0.467 deg, -2.846 deg) = (00 01 52, -02 50 45) (J2000) 
with a statistical 90% C.L. elliptical error region 
with long and short radii of 0.21 deg and 0.16 deg, respectively. 
The roll angle of the long axis from the north direction is 166.0 deg counterclockwise. 
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).
The above position is 5.6 arcminutes from the Swift/XRT 
position of GRB 180720B (Siegel et al. GCN 22973). 
The X-ray flux averaged over the scan was 191 +- 27 mCrab (4.0-10.0keV, 1 sigma error).
MAXI/GSC also detected the source at 25 +/- 12 mCrab in the next scan transit at 16:01.

The 2-20 keV GSC spectrum obtained in the scan transit at 14:28 is well described by 
an absorbed power-law with a photon index of 2.11 +/- 0.25 with n_H fixed at the total
Galactic column density to the direction of 3.5e20 atoms/cm2.


GRB_name: GRB180721A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22994
SUBJECT: GRB 180721A: Swift detection of a burst
DATE:    18/07/21 11:20:41 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

B. Sbarufatti (PSU), F. E. Marshall (NASA/GSFC) and
D. M. Palmer (LANL) report on behalf of the Neil Gehrels Swift
Observatory Team:

At 11:06:48 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180721A (trigger=849018).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 347.695, +4.880 which is 
   RA(J2000) = 23h 10m 47s
   Dec(J2000) = +04d 52' 47"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a multi-peaked
structure with a duration of about 60 sec.  The peak count rate
was ~1800 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 11:07:45.3 UT, 56.9 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source with an enhanced position: RA, Dec
347.7100, 4.8553 which is equivalent to:
   RA(J2000)  = 23h 10m 50.41s
   Dec(J2000) = +04d 51' 19.1"
with an uncertainty of 2.3 arcseconds (radius, 90% containment). This
location is 103 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
http://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
10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.7
(+3.22/-2.74) x 10^21 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 7.38e-10 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 250 seconds with the U filter starting
119 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 19.2 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 18.0 mag. No
correction has been made for the expected extinction corresponding to E(B-V) of
0.07. 

Burst Advocate for this burst is B. Sbarufatti (bxs60 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/too.html.)


GRB_name: GRB180721A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22995
SUBJECT: GRB 180721A: LCO Haleakala observations
DATE:    18/07/21 13:28:40 GMT
FROM:    Cristiano Guidorzi at Ferrara U,Italy  <guidorzi@fe.infn.it>

C. Guidorzi, R. Martone (U. Ferrara), S. Kobayashi (LJMU), C.G. Mundell 
(U. Bath), A. Gomboc (U. Nova Gorica), I.A. Steele (LJMU), A. Cucchiara, 
D. Morris (U. of Virgin Islands) on behalf of a large collaboration report:

The LCO 2-m unit at Haleakala Observatory (Hawaii) automatically began 
observing Swift GRB 180721A (Sbarufatti et al. GCN 22994) on July 21, 
11:21:40 UT (14.9 minutes after the GRB trigger time) with the SDSS i' 
filter. Within the Swift-XRT error circle we do not detect any source 
down to i'>20.2 mag at a mid time of 20.4 minutes post GRB with a 5x120s 
exposure, as calibrated against nearby SDSS objects.


GRB_name: GRB180720B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22996
SUBJECT: GRB 180720B: VLT/X-shooter redshift
DATE:    18/07/21 14:34:50 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

P. M. Vreeswijk (Radboud Univ. Nijmegen), D. A. Kann (HETH/IAA-CSIC), K. 
E. Heintz (Univ. Iceland and DAWN/NBI), A. de Ugarte Postigo 
(HETH-IAA/CSIC and DARK/NBI), B. Milvang-Jensen (DAWN/NBI), D. B. 
Malesani (DARK/NBI and DAWN/NBI), S. Covino (INAF/Brera), A. J. Levan 
(Univ. Warwick), G. Pugliese (Amsterdam), report on behalf of the 
Stargate collaboration:

We observed the optical counterpart of GRB 180720B (Siegel et al., GCN  
22973; Martone et al., GCN 22976) with the ESO VLT UT2 equipped with the 
X-shooter spectrograph. Two spectra of 600 s each were secured starting 
on 2018 July 21.384 UT (0.786 days after the GRB), covering the 
wavelength range 3000-25000 AA.

A bright continuum is detected across the entire observed range. Several 
absorption features are detected, which can be identified as due to Fe 
II, Mg II, Mg I, and Ca II, all at z = 0.654. We also identify 
fine-structure transitions due to both Fe II* and Ni II**, thus making 
the redshift association with the GRB secure.

We acknowledge the ESO observing staff at Paranal, in particular Juan 
Carlos Munoz, Emanuela Pompei, and Luca Sbordone.


GRB_name: GRB180721A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22997
SUBJECT: GRB 180721A: Enhanced Swift-XRT position
DATE:    18/07/21 15:29:16 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 1486 s of XRT Photon Counting mode data and 3 UVOT
images for GRB 180721A, 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 = 347.71167, +4.85678 which is equivalent
to:

RA (J2000): 23h 10m 50.80s
Dec (J2000): +04d 51' 24.4"

with an uncertainty of 2.8 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: GRB180720B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22998
SUBJECT: GRB 180720B: Swift-BAT refined analysis
DATE:    18/07/21 17:11:45 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

S. D. Barthelmy (GSFC), J. R. Cummings (CPI),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. H. Siegel (PSU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(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 180720B (trigger #848890)
(Siegel et al., GCN Circ. 22973).  The BAT ground-calculated position is
RA, Dec = 0.528, -2.925 deg which is
   RA(J2000)  =  00h 02m 06.8s
   Dec(J2000) = -02d 55' 31.3"
with an uncertainty of 1.2 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 8%.

The mask-weighted light curve shows a multi-peaked structure, with the main peak
occurs around ~T+11 s. The burst emission starts around ~T-20 s, although there might
be additional emission before the GRB came into the BAT FOV at ~T-57 s. The burst lasts
beyond the available event data range (until T+962 s). Analysis using the BAT survey data
shows that the burst emission extends at least till ~ T+2000 s, when Swift went into SAA
and no more data were collected. The burst came back into the BAT FOV at ~ T0+5626 s, and
the burst was no longer detected (signal-to-noise ratio < 3 sigma).

The time-averaged spectrum from T-20.0 to T+961.1 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.36 +- 0.03.  The fluence in the 15-150 keV band is 8.6 +- 0.1 x 10^-05 erg/cm2.
The 1-sec peak photon flux measured from T+10.94 sec in the 15-150 keV band
is 67.9 +- 2.6 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/848890/BA/


GRB_name: GRB180721A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  22999
SUBJECT: GRB 180721A: Swift-XRT refined Analysis
DATE:    18/07/21 18:10:31 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A.P. Beardmore (U. Leicester), A. D'Ai (INAF-IASFPA), A. Melandri
(INAF-OAB), P. D'Avanzo (INAF-OAB), S. J. LaPorte (PSU), J.A. Kennea
(PSU), P.A. Evans (U. Leicester), S.L. Gibson (U. Leicester) and B.
Sbarufatti report on behalf of the Swift-XRT team:

We have analysed 6.6 ks of XRT data for GRB 180721A (Sbarufatti et al.
GCN Circ. 22994), from 63 s to 17.7 ks after the  BAT trigger. The data
comprise 17 s in Windowed Timing (WT) mode with the remainder in Photon
Counting (PC) mode. The enhanced XRT position for this burst was given
by Goad et al. (GCN Circ. 22997).

The light curve can be modelled with an initial power-law decay with an
index of alpha=2.9 (+0.8, -0.5), followed by a break at T+203 s to an
alpha of 0.84 (+/-0.07).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.14 (+0.24, -0.23). The
best-fitting absorption column is  1.4 (+0.7, -0.6) x 10^21 cm^-2, in
excess of the Galactic value of 6.5 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.2 x 10^-11 (4.3 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.4 (+0.7, -0.6) x 10^21 cm^-2
Galactic foreground: 6.5 x 10^20 cm^-2
Excess significance: 2.1 sigma
Photon index:      2.14 (+0.24, -0.23)

If the light curve continues to decay with a power-law decay index of
0.84, the count rate at T+24 hours will be 3.6 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 1.2 x
10^-13 (1.6 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/00849018.

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


GRB_name: GRB180720C
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23000
SUBJECT: GRB 180720C: Swift-BAT refined analysis
DATE:    18/07/21 19:01:08 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

J. R. Cummings (CPI), S. D. Barthelmy (GSFC),
H. A. Krimm (NSF/USRA), S. J. LaPorte (PSU),
A. Y. Lien (GSFC/UMBC), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(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 180720C (trigger #848932)
(LaPorte et al., GCN Circ. 22982).  The BAT ground-calculated position is
RA, Dec = 265.655, -26.634 deg which is
  RA(J2000)  =  17h 42m 37.1s
  Dec(J2000) = -26d 38' 02.5"
with an uncertainty of 1.7 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 98%.

The mask-weighted light curve shows a main single-pulse structure that
starts at ~T-20 s, peaks at ~T0, and ends at ~T+20 s. In addition, there are
some weak emission prior to this main pulse, starting at ~T-150 s.
T90 (15-350 keV) is 124.2 +- 32.7 sec (estimated error including systematics).

The time-averaged spectrum from T-150.52 to T+23.34 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.39 +- 0.13.  The fluence in the 15-150 keV band is 2.4 +- 0.2 x 10^-6 erg/cm2.
The 1-sec peak photon flux measured from T-0.27 sec in the 15-150 keV band
is 1.1 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The temporal and spectral characteristics of this burst are
consistent with those of a long GRB.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/848932/BA/


GRB_name: GRB180721A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23001
SUBJECT: GRB 180721A: Swift-BAT refined analysis
DATE:    18/07/21 19:01:43 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

H. A. Krimm (NSF/USRA), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), D. M. Palmer (LANL),
T. Sakamoto (AGU), B. Sbarufatti (PSU),
M. Stamatikos (OSU), T. N. Ukwatta (LANL)
(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 180721A (trigger #849018)
(Sbarufatti et al., GCN Circ. 22994).  The BAT ground-calculated position is
RA, Dec = 347.708, 4.871 deg which is
  RA(J2000)  =  23h 10m 49.9s
  Dec(J2000) = +04d 52' 16.1"
with an uncertainty of 1.8 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 100%.

The mask-weighted light curve shows a single-pulse structure that starts
at ~T-1 s, peaks at ~T+2 s, and ends at ~T+10 s. The main pulse is followed
by some weak emission that last till ~T+50 s. T90 (15-350 keV) is 47.6 +- 3.0 sec
(estimated error including systematics).

The time-averaged spectrum from T-0.39 to T+48.92 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.25 +- 0.22.  The fluence in the 15-150 keV band is 5.9 +- 0.9 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+1.82 sec in the 15-150 keV band
is 0.9 +- 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/849018/BA/


GRB_name: GRB180711A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23002
SUBJECT: GRB 180711A: AstroSat CZTI detection
DATE:    18/07/21 19:34:43 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:

Analysis of Astrosat CZTI data showed the detection of a GRB 180711A, which was also detected by CALET (Sakamoto T. et al., GCN 22943).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with the strongest peak at 17:02:02.5 UT. The measured peak count rate is 327.3 cts/s above the background in combined data of four quadrants, with a total of 1186 cts. The local mean background count rate was 494.7 cts/s. Using cumulative rates, we measure a T90 of 4.9 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: GRB180720C
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23003
SUBJECT: GRB 180720C: Swift-XRT refined Analysis
DATE:    18/07/21 19:36:09 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), J.A.
Kennea (PSU), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU), P.A.
Evans (U. Leicester), S.L. Gibson (U. Leicester), Z. Liu (NAOC / U.
Leicester) and S.J. LaPorte report on behalf of the Swift-XRT team:

We have analysed 7.2 ks of XRT data for GRB 180720C (LaPorte et al. GCN
Circ. 22982), from 105 s to 69.3 ks after the  BAT trigger. The data
are entirely in Photon Counting (PC) mode. The enhanced XRT position
for this burst was given by Evans et al. (GCN Circ. 22987).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.59 (+/-0.07).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 2.1 (+0.6, -0.5). The
best-fitting absorption column is  2.8 (+1.2, -1.0) x 10^22 cm^-2, in
excess of the Galactic value of 6.8 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 6.7 x 10^-11 (1.7 x 10^-10) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.8 (+1.2, -1.0) x 10^22 cm^-2
Galactic foreground: 6.8 x 10^21 cm^-2
Excess significance: 3.7 sigma
Photon index:      2.1 (+0.6, -0.5)

If the light curve continues to decay with a power-law decay index of
0.59, the count rate at T+24 hours will be 6.3 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 4.2 x
10^-13 (1.1 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/00848932.

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


GRB_name: GRB180720B
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23004
SUBJECT: GRB 180720B: MITSuME Ishigaki optical observations
DATE:    18/07/22 00:04:42 GMT
FROM:    Ryosuke Itoh at Tokyo Institute of Tech.  <itoh@hp.phys.titech.ac.jp>

T. Horiuchi,  H. Hanayama, M. Honma (IAO, NAOJ),
R. Itoh, K. L. Murata, Y. Tachibana, S. Harita, K. Morita
K. Shiraishi, K. Iida, M. Oeda, R. Adachi, S. Niwano,
Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We observed the optical counterpart of GRB 180720B
(Siegel et al., GCN 22973)
with the optical three color (g', Rc, and Ic) CCD cameras attached to
the Murikabushi 1m telescope of Ishigakijima Astronomical Observatory, Japan.

The observation started on 2018-07-20 17:11:26 UT, (~2.8 hours after
the burst). We detected the previously reported afterglow
(Martone et al., GCN 22976, Sasada et al., GCN 22977, Reva et al., GCN 22979)
in the Rc and Ic band.

The photometric results of the OT are listed below.
We used UCAC-4 catalog for flux calibration.

#T0+[hour]  MID-UT    T-EXP[sec] Rc   Ic
-------------------------------------------------------------------
2.8    17:14:58   240  16.23+/-0.03 16.24+/-0.05
-------------------------------------------------------------------
T0+ : Elapsed time after the burst [hour]
T-EXP: Total Exposure time [sec]


GRB_name: GRB180722A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23005
SUBJECT: GRB 180722A: MAXI/GSC detection
DATE:    18/07/22 07:26:39 GMT
FROM:    H. Negoro at Nihon U.  <negoro@phys.cst.nihon-u.ac.jp>

R. Shimomukai (JAXA), H. Negoro (Nihon U.), W. Iwakiri (Chuo U.), 
M. Nakajima, W. Maruyama, A. Sakamaki (Nihon U.), 
T. Mihara, S. Nakahira, F. Yatabe, Y. Takao, M. Matsuoka (RIKEN), 
N. Kawai, M. Sugizaki, Y. Tachibana, K. Morita (Tokyo Tech), 
T. Sakamoto, M. Serino, S. Sugita, Y. Kawakubo, T. Hashimoto, A. Yoshida (AGU), 
S. Ueno, H. Tomida, M. Ishikawa, Y. Sugawara, N. Isobe (JAXA), 
Y. Ueda, A. Tanimoto, T. Morita, S. Yamada (Kyoto U.), Y. Tsuboi, R. Sasaki, 
H. Kawai, T. Sato (Chuo U.), H. Tsunemi, T. Yoneyama (Osaka U.), 
M. Yamauchi, K. Hidaka, S. Iwahori (Miyazaki U.), T. Kawamuro (NAOJ), 
K. Yamaoka (Nagoya U.), M. Shidatsu (Ehime U.) 
report on behalf of the MAXI team:

The MAXI/GSC nova alert system triggered on a bright uncatalogued X-ray 
transient source at 05:59:06 UT on 2018 July 22.
Assuming that the source flux was constant over the transit,
we obtain the source position at
(R.A., Dec) = (302.894 deg, 24.221 deg) = (20 11 34, +24 13 15) (J2000) 
with a statistical 90% C.L. elliptical error region 
with long and short radii of 0.21 deg and 0.17 deg, respectively. 
The roll angle of the long axis from the north direction is 14.0 deg counterclockwise. 
There is an additional systematic uncertainty of 0.1 deg (90% containment radius).

We estimated a rectangular error box for the transient source with the following corners:
(301.985, 24.469) deg = (20 07 56, +24 28 07) (J2000)
(301.898, 24.157) deg = (20 07 35, +24 09 26) (J2000)
(303.593, 23.939) deg = (20 14 22, +23 56 18) (J2000)
(303.685, 24.249) deg = (20 14 44, +24 14 56) (J2000)

The X-ray flux averaged over the scan was 259 +- 32 mCrab
(4.0-10.0keV, 1 sigma error).

There was no significant excess flux in the previous transit at UT 04:26.


GRB_name: GRB180722A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23006
SUBJECT: GRB 180722A: MASTER optical observation
DATE:    18/07/22 08:18:13 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, N.Tiurina, 
V.Kornilov, A.Kuznetsov, V.Chazov, I.  Gorbunov,
D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov, D.Vlasenko
Lomonosov Moscow State University,SAI

D. Buckley,
South African Astronomical Observatory (SAAO)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias (IAC)

A. Tlatov, V.Senik, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

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

H.Levato,
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University (ISU)

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



MASTER-OAFA robotic telescope (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  GRB180722A( Shimomukai et al., MAXI/GSC detection, GCN #23005)
17  sec after notice  time and 2572 sec after trigger  time at 2018-07-22 
06:42:08 UT. On our  first (180s exposure)  set we  not found optical 
transient within MAXI error-box (ra=302.613 dec=24.2364  r=1) brighter 
then 17.7.


The observations made on zenit distance = 62 degrees, galaxy latitude b = 
-5 degrees.
The moon (74 % bright part) is  4 degrees above the horizon. The distance 
between  moon and  object is 75 .
The sun  altitude  is -61.0 degree.
The object can be observed till 2018-07-22 09:45:34.

  The message may be cited.


GRB_name: GRB180720C
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23009
SUBJECT: GRB 180720C: MASTER optical observation 
DATE:    18/07/22 08:51:43 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

E. Gorbovskoy, V.Lipunov, N.Tiurina, V. Lipunov, V.Kornilov, A.Kuznetsov, 
V.Chazov, I.  Gorbunov, D.Zimnukhov, D.Kuvshinov, P.Balanutsa, 
V.Vladimirov, D.Vlasenko
Lomonosov Moscow State University,SAI

D. Buckley,
South African Astronomical Observatory (SAAO)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias (IAC)

A. Tlatov, V.Senik, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

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

H.Levato,
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University (ISU)

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

MASTER-Kislovodsk robotic telescope (MASTER-Net: 
http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, 
vol. 2010, 30L) located in Russia (Lomonosov MSU, Kislovodsk Solar Station 
of Pulkovo observatory) was pointed to the  GRB180720C 21 sec after notice 
time and 102 sec after trigger time at 2018-07-20 22:25:39 UT.


MASTER-IAC robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
Spain (IAC Teide Observatory) was pointed to the  GRB180720C 258 sec after 
notice time and 1668 sec after trigger time at 2018-07-20 22:56:57 UT.

MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
South Africa (South African Astronomical Observatory) was pointed to the 
GRB180720C 30 sec after notice time and 111 sec after trigger time at 
2018-07-20 22:25:48 UT.

MASTER-OAFA robotic telescope (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  GRB180720C 21 sec after notice time and 102 sec after trigger time 
at 2018-07-20 22:25:39 UT.


We have a number of images on this observatories. The observations made 
very  close to Galactic center (~ 1 degree).  The upper limit on 
observaroties is about 18 mag.

The message may be cited.


GRB_name: GRB180720B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23011
SUBJECT: Konus-Wind observation of GRB 180720B
DATE:    18/07/22 13:43:39 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

D. Frederiks, S. Golenetskii, R.Aptekar, A. Kozlova,
A.Lysenko,  D. Svinkin, A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The long, extremely bright GRB 180720B
(Swift-BAT detection: Siegel et al., GCN 22973, GCN 22975;
Fermi-LAT detection: Bissaldi and Racusin, GCN 22980;
Fermi-GBM detection: Roberts et al., GCN 22981)
triggered Konus-Wind at T0=51705.261 s UT (14:21:45.261).

The burst light curve shows a multi-peaked structure
with a total duration (T100) of ~125 s.
The emission is seen up to ~15 MeV.

As observed by Konus-Wind, the burst had a fluence of
(5.43 Â± 0.26)x10^-4 erg/cm2 and a 64-ms peak energy flux,
measured from T0+15.168, of (9.70 Â± 0.52)x10^-5 erg/cm2
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+119.808 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 = -1.01 (-0.06,+0.06),
the high energy photon index beta = -2.07 (-0.08,+0.07),
the peak energy Ep = 451 (-45,+52) keV,
chi2 = 102/97 dof.

The spectrum near the peak count rate (measured from T0+14.592 s
to T0+15.360 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 = -0.82 (-0.09,+0.10),
the high energy photon index beta = -2.27 (-0.22,+0.13),
the peak energy Ep = 779 (-127,+169) keV,
chi2 = 92/76 dof.

Assuming the redshift z=0.654 (Vreeswijk et al., GCN 22996)
and a standard cosmology model with H_0 = 70 km/s/Mpc,
Omega_M = 0.30, and Omega_Lambda = 0.70,
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is ~6.0x10^53 erg,
the peak luminosity L_iso is ~1.8x10^53 erg/s,
and the rest-frame peak energy of the time-integrated spectrum,
Ep,z, is ~746 keV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB180720_T51705/

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


GRB_name: GRB180715A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23012
SUBJECT: GRB 180715A: AstroSat CZTI detection
DATE:    18/07/22 14:53:11 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:

Analysis of Astrosat CZTI data showed the detection of a GRB 180715A, which was also detected by Swift (Palmer D. et al., GCN 22947), Fermi-GBM (Hamburg R. et. al., GCN 22952) and CALET (Torii S. et al.,GCN 22956).

The source was clearly detected in the 40-200 keV energy range. The light curve shows a single peak of emission with peak at 18:06:59.5 UT. The measured peak count rate is 403.6 cts/s above the background in combined data of four quadrants, with a total of 408 cts. The local mean background count rate was 476.4 cts/s. Using cumulative rates, we measure a T90 of 0.9 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: GRB180715B
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23013
SUBJECT: GRB 180715B: AstroSat CZTI detection
DATE:    18/07/22 15:04:34 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:

Analysis of Astrosat CZTI data showed the detection of a short GRB 180715B, which was also detected by Fermi-GBM (trigger # 553369644, 17:47:19.090 UT) and Zwicky Transient Facility (Cenko S. B. et al., GCN 22969)

The source was clearly detected in the 40-200 keV energy range. The light curve shows a single peak of emission with peak at 17:47:19.5 UT, ~4 s after the GBM trigger. The measured peak count rate is 412.5 cts/s above the background in combined data of four quadrants, with a total of 604 cts. The local mean background count rate was 540.5 cts/s. Using cumulative rates, we measure a T90 of 1.7 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: GRB180721A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23014
SUBJECT: GRB 180721A: Swift/UVOT Upper Limits
DATE:    18/07/22 16:42:55 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

N. P. M. Kuin (UCL-MSSL) and B. Sbarufatti (PSU)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180721A
120 s after the BAT trigger (Sbarufatti et al., GCN Circ. 22994).
No optical afterglow consistent with the XRT position (Goad et al, GCN
Circ. 22997) 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

u_FC               120          370          246         >20.1
v                  425         1693          156         >19.1
b                  375         1642          175         >19.9
u                  120         1617          529         >20.1
w1                 474         1742          156         >19.6
m2                1697         1717           19         >18.3
w2                 401         1668          156         >20.5

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.07 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB180722A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23015
SUBJECT: GRB 180722A: Tiled Swift observations
DATE:    18/07/22 18:42:16 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 180722A. Automated analysis of the XRT data will
be presented online at http://www.swift.ac.uk/xrt_products/TILED_GRB00071

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: GRB180720C
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23016
SUBJECT: GRB 180720C: BOOTES-2/TELMA optical observations
DATE:    18/07/22 18:53:13 GMT
FROM:    Alberto Castro-Tirado at Inst.de Astro. de Andalucia  <ajct@iaa.es>

C. Perez del Pulgar and A. Castellon (Univ. de Malaga), E. 
Fernandez-Garcia, Y. Hu, I. Carrasco
and A. J. Castro-Tirado (IAA-CSIC), on behalf of a larger collaboration, 
report:

The 60cm BOOTES-2/TELMA robotic telescope at IHSM La Mayora (UMA-CSIC) 
in Algarrobo Costa (Spain) automatically
responded in 53s (and 132s after the GRB onset) to the Swift trigger of 
GRB 180720C (LaPorte et al., GCNC 22982).
The first image (10s exposure, unfiltered) was obtained at 22:26:09 UT. 
At the position of the Swift X-ray
afterglow (Evans et al. GCNC 22987), no optical afterglow is detected 
down 18 mag in this crowded field in
the direction of the Galactic Center (i.e. high extinction towards the 
source is very likely present).
This is consistent with the limits reported by Guidorzi et al. (GCNC 
22991), Oates et al. (GCNC 22992) and
Gorbovskoy et al. (GCNC 23009).

The message may be cited.


GRB_name: GRB180720B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23017
SUBJECT: GRB 180720B: COATLI Optical Detection 
DATE:    18/07/22 20:52:09 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), William
H. Lee (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Alexander Kutyrev (GSFC), and
Eleonora Troja (GSFC) report:

We observed the field of GRB 180720B (Siegel et al., GCN Circ. 22973)
with the COATLI 50-cm telescope and interim imager at the Observatorio
AstronÃ³mico Nacional on the Sierra de San Pedro MÃ¡rtir
(http://coatli.astroscu.unam.mx) from 2018-07-22 06:25 to 11:23 UTC
(from 40.07 to 45.03 hours after the trigger), obtaining a total of 4.06
hours of exposure in the w filter.

We detect the optical counterpart (Martone et al., GCN Circ. 22976) with

w = 20.07 +/- 0.02

These magnitudes are calibrated against the USNO-B1 catalog (adjusted to
an approximate AB system) and are not corrected for Galactic extinction
in the direction of the GRB.

We thank the COATLI technical team (Fernando Ãngeles, Oscar Chapa,
Salvador Cuevas, Alejandro Farah, Jorge Fuentes, RosalÃ­a Langarica,
Fernando QuirÃ³s, and Carlos Tejada) and the staff of the Observatorio
AstronÃ³mico Nacional.


GRB_name: GRB180721A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23018
SUBJECT: GRB 180721A: BOOTES-5/JGT optical observations
DATE:    18/07/22 20:55:42 GMT
FROM:    Irene Carrasco at Inst.De Astrofisica de Andalucia  <irene@iaa.es>

I. Carrasco (Univ. de Malaga), Y. Hu, E. Fernandez-Garcia, J. C. Tello 
and A. J. Castro-Tirado (IAA-CSIC),
D. Hiriart and W. H. Lee (UNAM), S. Jeong and I. H. Park (SKKU), M. D. 
Caballero-Garcia (ASU-CAS, CZ) and
R. Cunniffe (Inst. of Physics, CZ) on behalf of a larger collaboration, 
report:

The 60cm BOOTES-5/JGT robotic telescope at Observatorio Astronomico 
Nacional in San Pedro Martir (Mexico)
automatically responded in 21s (and 53s after the GRB onset) to the 
Swift trigger of GRB 180721A (Sbarufatti
et al., GCNC 22994). The first image (10s exposure, r-band) was obtained 
at 11:07:10 UT. At the position of
the Swift X-ray afterglow (Goad et al. GCNC 22997), no optical afterglow 
is detected down 18.1 mag. Furthermore,
on the co-add of the images obtained until 11:33:52 UT no afterglow is 
detected down to 21 mag, consistent with
the limit reported by Guidorzi et al. (GCNC 22995).

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


GRB_name: GRB180720B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23019
SUBJECT: GRB 180720B: Testing the universality of the newly born neutron star in BdHNe
DATE:    18/07/22 22:30:27 GMT
FROM:    Remo Rufinni at ICRA  <ruffini@icra.it>

R. Ruffini, Y. Aimuratov, C. L. Bianco, Y. C. Chen, D. M. Fuksman, M. Karlica, R. Moradi, D. Primorac, J.A. Rueda, N. Sahakyan, Y. Wang, on behalf of the ICRANet team, report:

GRB 180720B (Siegel et al., GCN 22973) is a long GRB with isotropic energy ~6.0e53 erg (Frederiks et al., GCN 23011). It belongs to the long GRB subclass of Binary Driven Hypernovae (BdHNe) (Ruffini et al., 2016, ApJ, 832, 136), with energies larger than 1e52 erg and GeV radiation, which allows the determination of the black hole mass (Ruffini et al., arXiv:1803.05476). It includes GRB 130427A associated to SN 2013cq (Ruffini et al., GCN 14526, Xu et al., GCN 14646), as well as GRB 160625B (Troja et al., 2017). The comparison of X-ray light-curves is attached [1], plotted in the rest frame of the sources. These sources are polar views from the normal to the plane of the binary progenitor (Ruffini et al., arXiv:1803.05476). In GRB 180720B, which has redshift z = 0.654 (GCN 22996), being a BdHN, a supernova is expected to peak, using the averaged observed value (Cano et al., 2016), at 21.8 +/ 4.3 day after the trigger (11 August 2018, uncertainty from August 7th to August 15th): the prolonged observations of the afterglow in all bands, especially the optical band, is recommended to further probe the nature of the supernova and of the newly born neutron star, strikingly constant in all BdHNe (see also Becerra et al., arXiv:1803.04356).


[1] Link: http://www.icranet.org/documents/20180721.jpg

Caption of figure: Three BdHNe with polar views from the normal to the plane of the binary progenitor, pointing to the similarities. GRB 130427A with redshift z=0.34 is associated to the companion supernova SN 2013cq. GRB 160625B has redshift z=1.406, which is too far for the optical observation of the associated supernova (Woosley & Bloom, 2006). GRB 180720B with redshift z=0.654 is expected to have the observation of an associated supernova.


GRB_name: GRB180720B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23020
SUBJECT: GRB 180720B:  ISON-Castelgrande optical observations
DATE:    18/07/22 23:39:09 GMT
FROM:    Alexei Pozanenko at IKI, Moscow  <apozanen@iki.rssi.ru>

S. Schmalz (KIAM), F. Graziani (GAUSS). A. Pozanenko (IKI), A. Volnova 
(IKI),  E. Mazaeva  (IKI),  I. Molotov (KIAM) report on behalf of larger GRB 
follow-up collaboration:

We observed the field of GRB 180720B (Swift-BAT detection: Siegel et al., 
GCN 22973, GCN 22975; Fermi-LAT detection: Bissaldi and Racusin, GCN 22980; 
Fermi-GBM detection: Roberts et al., GCN 22981; MAXI/GSC detection: Negoro 
et al., GCN 22993; Konus-Wind detection:  Frederiks et al., GCN 23011) 
with  ORI-22 (22 cm) telescope of ISON-Castelgrande observatory starting on 
July 20  (UT) 23:04:30.  We obtained 150 images of 60 s exposure in Clear 
filter.  The optical afterglow (e.g. Martone et al. GCN 22976;  Sasada et 
al., GCN 22977;  Reva et al., GCN 22979; Itoh et al., GCN 22983; Kann et 
al., GCN 22985)  is  detected in  separate images up to the end of series.

The coordinates of the optical afterglow are (J2000) 
:02:06.792   -02:55:04:99  with uncertainties of about 0.5 arcsec in both 
coordinates.  Preliminary photometry  of the  afterglow at  (UT, mid time) 
23:22:21 is R =17.40 +/- 0.15. The photometry is  based on nearby USNO-B1.0 
(R2) stars.


GRB_name: GRB180720B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23021
SUBJECT: GRB 180720B: REM photometry
DATE:    18/07/23 09:43:43 GMT
FROM:    Stefano Covino at Brera Astronomical Observatory  <stefano.covino@gmail.com>

S.Covino, D. Fugazza (INAF/OAB), on behalf of the REM team, report:

We observed the field of GRB180720B (Siegel et al. GCN 22973) with the REM 60cm robotic telescope located at the ESO premise of La Silla (Chile).
The observations were performed starting from about 13.5 hours after the event and were carried in the g, r, i, z, J, H and K bands. 

The optical counterpart (Martone et al. GCN 22976) is still detected in the optical and in the NIR bands. A preliminary photometry on the first H band set of frame gives:

H = 15.65 +- 0.22 at 13.7 hours from the GRB time.

Magnitudes are calibrated against the 2MASS catalogue.


GRB_name: GRB180721A
Detection_method: MITSuME
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23022
SUBJECT: GRB 180721A: MITSuME Akeno optical upper limits
DATE:    18/07/23 09:52:13 GMT
FROM:    Ryosuke Itoh at Tokyo Institute of Tech.  <itoh@hp.phys.titech.ac.jp>

M. Oeda, R. Itoh, K. L. Murata, Y. Tachibana, S. Harita, K. Morita,
K. Shiraishi, K. Iida, R. Adachi, S. Niwano,
Y. Yatsu, and N. Kawai (Tokyo Tech)
report on behalf of the MITSuME collaboration:

We searched for the optical counterpart of GRB 180721A
(B. Sbarufatti et al., GCN Circular #22994)
with the optical three color (g', Rc, and Ic) CCD cameras attached to
the MITSuME 50cm telescope of Akeno Observatory, Yamanashi, Japan.

The observation started on 2018-07-21 13:44:45.05 UT.
We did not find any point source at the enhanced position of the
XRT error circle (M.R. Goad et al., GCN Circular #22997) in all three bands.
We obtained following 5-sigma upper limits for the magnitudes.

T0+[min]    MID-UT      T-EXP[sec]    g'       Rc        Ic
-------------------------------------------------------------------------------------------------------
157.95     14:27:28  4,740   >16.9   >17.3   >16.9
-------------------------------------------------------------------------------------------------------
T0+ : Elapsed time after the burst
T-EXP: Total Exposure time
We used UCAC-4 catalog for flux calibration.


GRB_name: GRB180720B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23023
SUBJECT: GRB 180720B: MASTER Global Net OT observations 
DATE:    18/07/23 11:57:20 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, N.Tiurina, D.Vlasenko, V.Kornilov, A.Kuznetsov, 
V.Chazov, I.  Gorbunov, D.Zimnukhov, D.Kuvshinov, P.Balanutsa,
V.Vladimirov,
Lomonosov Moscow State University,SAI

D. Buckley,
South African Astronomical Observatory (SAAO)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias (IAC)

A. Tlatov, V.Senik, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

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

H.Levato,
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University (ISU)

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

MASTER-Amur robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
Russia (Blagoveschensk State Pedagogical University) was pointed to the 
Swift GRB180720B (Siegel et al., GCN Circ #22973) 113 sec after trigger 
time at 2018-07-20 14:23:37 UT.
So as the GRB was 4.6 degrees above the horizont, the good observations 
started on 2018-07-20 15:21:50UT.

Galaxy latitude b = -63.07 degree.
The moon (58 % bright part) is 9 degrees above the horizon. The distance 
between  moon and  object was 143.
The sun  altitude  was -17.19 degree.
The object observed till 2018-07-20 15:47:58

MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
South Africa (South African Astronomical observatory) was pointed to 
GRB180720B 27260 sec after trigger time at 2018-07-19 20:56:09 UT as 
MASTER's LAT (Bissaldi et al GCN22980)alert inspection with polarization 
filters.

MASTER-SAAO auto-detection system ( Lipunov et al., "MASTER Global Robotic 
Net", Advances in Astronomy, 2010, 30L )
  discovered bright OT source at (RA, Dec) = 00h 02m 06.92s -02d 55m 05.6s 
on  2018-07-19 20:56:09  UT.

The OT  magnitude is ~16.8m .

There is no minor planet at this place.
We have reference image on 2016-05-04.12293 UT with  unfiltered mlim =  18.1m.


The observations made on zenit distance = 16.7 degrees, galaxy latitude b 
= -74.37 degree. The moon (61 % bright part) was 24 degrees above the 
horizon.The sun  altitude  was -63.7 degree.

MASTER-SAAO reobserved this area on 2018-07-21 22:28:10-22:54:51UT as 
MASTER's MAXI (Negoro et al GCN 22993)  alert inspection  with mlim=20.2 
and unfiltered m_OT~19.1

The discovery and reference images are 
http://master.sai.msu.ru/static/OT/MASTERGRB180720B.jpg


MASTER-Kislovodsk robotic telescope (MASTER-Net: 
http://observ.pereplet.ru, Lipunov et al., 2010, Advances in Astronomy, 
vol. 2010, 30L) located in Russia (Pulkovo Solar Station) was pointed to 
the GRB180720B (Siegel et al., GCN Circ #22973) 27457 sec after trigger 
time at 2018-07-20 21:59:21 UT .
On our first (180s exposure)  set MASTER-Kislovodsk auto-detection system 
discovered OT with m_OT~17.0,  automatical  mlim~17.6.

The observations made on zenit distance = 25.66 degrees, galaxy latitude b 
= -63.07 degree.
The moon (61 % bright part) is below the horizon(The altitude of Moon is 
-8). The distance between  moon and  object is 138
The sun  altitude  is -24.87 degree.
The object observed till 2018-07-20 22:19:52

MASTER-IAC robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
Spain (IAC Teide Observatory) was pointed to the GRB180720B (Siegel et 
al., GCN Circ #22973) 44691 sec after trigger time at 2018-07-21 02:46:35 
UT . On our first (60s exposure)  MASTER-IAC auto-detection system 
discovered  optical transient within Swift error-box  with automatical 
magnitude ~18.0.

The observations made on zenit distance = 43.01 degrees, galaxy latitude b 
= -63.07 degree.
The moon (63 % bright part) is below the horizon(The altitude of Moon is 
-15). The distance between  moon and  object is 136
The sun  altitude  is -36.01 degree.
The object observed till 2018-07-21 03:03:36

The visibility GRB error box (coord:0.5279, -2.9170 error_box: 0.05)
at trigger time at different MASTER sites:

obj: -47.70 sun:  29.73 - Tavrida (Crimea, Russia)
obj: -41.62 sun:  72.28 - IAC, Teide, (Tenerife, Spain)
obj: -54.25 sun:  15.39 - SAAO (Sutherland, SA)
obj: -46.85 sun:  23.59 - Kislovodsk (Russia)
obj: -29.98 sun:  15.28 - Ural(Kourovka, Russia)
obj: -10.74 sun: -8.46  - Tunka (near Baykal Lake, Russia)
obj:  4.55  sun: -17.19 - Amur(Blagoveschensk)
obj:  6.72  sun:  27.64 - OAFA (Argentina)


The message may be cited.


GRB_name: GRB180720B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23024
SUBJECT: GRB 180720B: D50 optical observations
DATE:    18/07/23 20:21:57 GMT
FROM:    Jan Strobl at AI AS CR,Ondrejov  <jan@strobl.cz>

M. Jelinek, J. Strobl, R. Hudec, C. Polasek (ASU CAS Ondrejov)
report:

We observed the position of the bright GRB 180720B (Siegel et al., GCN 
22973 & GCN 22975) with the D50 telescope of the Astronomical Institute 
Ondrejov, near Prague, Czech Republic. We performed a series of ~300x 20s 
unfiltered exposures as soon as the position became accessible above local 
horizon, between 9.8 and 12h after the trigger.

The optical afterglow (Martone et al., GCN 22976; Sasada et al., GCN 
22977; Reva et al., GCN 22979; Itoh et al., GCN 22983) is clearly detected 
in single 20 s images.

We confirm the stationary behaviour during our observations as reported by 
Kann et al. (GCN 22985) - the afterglow might have faded as few as 0.04 
mag between 10 and 11h after the GRB trigger.


GRB_name: GRB180722A
Detection_method: MAXI Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23026
SUBJECT: GRB 180722A: MASTER second inspection
DATE:    18/07/24 10:16:15 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, N.Tiurina, D.Vlasenko, V.Kornilov, A.Kuznetsov, 
V.Chazov, I.  Gorbunov, D.Zimnukhov, D.Kuvshinov, P.Balanutsa,
V.Vladimirov,
Lomonosov Moscow State University,SAI

D. Buckley,
South African Astronomical Observatory (SAAO)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias (IAC)

A. Tlatov, V.Senik, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

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

H.Levato,
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University (ISU)

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


MASTER-SAAO  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in SAAO was starting second survey on the MAXI  GRB180722A 
error-box 
(ra=20 11 34 dec=+24 13 15 r=1)  61549 sec after notice time and 65839 sec 
after trigger time at 2018-07-23 00:16:35 UT (Shimomukai et al., 
MAXI/GSC detection, GCN #23005; Lipunov et al., GCN #23006). The 5-sigma 
upper limit on our first (180s exposure)  set is about 19.0  mag

This error-box was observed by MASTER-Amur ( 2018-07-23 
12:53:17-14:00:20UT, 60s, mlim=17.8) and another MASTER sites.

The coverage  map of the 3 sigms error box is available at
http://master.sai.msu.ru/static/OT/MASTERMAXIGRB180722A.jpg

The observations made on zenit distance = 61 degrees, galaxy latitude b = 
-6 degree.
The moon (80 % bright part) is 17 degrees above the horizon. The distance 
between  moon and  object is 69
The sun  altitude  is -65.7 degree.
The object can be observed till 2018-07-23 03:41:44




The message may be cited.


GRB_name: GRB180722B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23028
SUBJECT: GRB 180722B: CALET Gamma-Ray Burst Monitor detection
DATE:    18/07/24 11:07:33 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

T. Tamura (Kanagawa U), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita,
Y. Kawakubo, A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito,
H. Morita, Y. Sone (AGU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
I. Takahashi (IPMU), Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
Y. Shimizu (Kanagawa U), W. Ishizaki (ICRR), M. L. Cherry (LSU),
S. Ricciarini (U of Florence), A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long GRB 180722B (Fermi-GBM trigger #553996158; Konus-Wind
trigger time on 23:49:18.90 UT) triggered the CALET Gamma-ray
Burst Monitor (CGBM) at 23:49:16.174 UTC on 22 July 2018.
Because of a problem in one of the ground alert processing script,
the GCN notice was not distributed automatically for this event.

The burst light curve shows two broad pulses which start
at T-4.0 sec and end at T+39.9 sec.
The T90 and the T50 durations measured by the SGM data are
40.1 +- 3.2 sec and 30.0 +- 1.7 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1216338436/

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


GRB_name: GRB180723A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23029
SUBJECT: GRB 180723A: CALET Gamma-Ray Burst Monitor detection
DATE:    18/07/24 11:09:44 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

W. Ishizaki (ICRR), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita,
Y. Kawakubo, A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito,
H. Morita, Y. Sone (AGU), K. Yamaoka (Nagoya U), S. Nakahira (RIKEN),
I. Takahashi (IPMU), Y. Asaoka, S. Ozawa, S. Torii (Waseda U),
Y. Shimizu, T. Tamura (Kanagawa U), M. L. Cherry (LSU),
S. Ricciarini (U of Florence), A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The long GRB 180723A (Fermi-GBM trigger #554062193) triggered the CALET
Gamma-ray Burst Monitor (CGBM) at 18:09:45.493 UTC on 23 July 2018.
This GRB is also clearly seen by the publicly available INTEGRAL
SPI-ACS light curve.  The burst signal was seen by all CGBM detectors.

The burst light curve shows a FRED-like pulse which starts
at T+2.4 sec, peaks at T+4.9 sec, and ends at T+14.5 sec.
The T90 and the T50 durations measured by the SGM data are
10.0 +- 1.3 sec and 4.3 +- 0.7 sec (40-1000 keV), respectively.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1216404464/

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


GRB_name: GRB180718A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23030
SUBJECT: GRB 180718A: Swift-XRT observations
DATE:    18/07/24 13:37:13 GMT
FROM:    Boris Sbarufatti at PSU  <bxs60@psu.edu>

J.P. Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore
(U. Leicester), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), A. D'Ai
(INAF-IASFPA), D.N. Burrows (PSU), A. Tohuvavohu (PSU), S. J. LaPorte
(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-detected burst GRB 180718A (Svinkin et al. GCN Circ. 22959),
collecting 1.5 ks of Photon Counting (PC) mode data between T0+113.7 ks
and T0+115.2 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
ranges from ~0.005 to ~0.013 ct s^-1, corresponding to a 0.3-10 keV
observed flux of 2.1e-13 to 5.1e-13 erg cm^-2 s^-1 (assuming a typical
GRB spectrum).

The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
http://www.swift.ac.uk/ToO_GRBs/00020802.

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


GRB_name: GRB180718B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23031
SUBJECT: GRB 180718B: Swift-XRT observations
DATE:    18/07/24 14:21:22 GMT
FROM:    Boris Sbarufatti at PSU  <bxs60@psu.edu>

B. Sbarufatti (INAF-OAB/PSU), A. A. Breeveld (UCL-MSSL), Z. Liu (NAOC /
U. Leicester), J.P. Osborne (U. Leicester), K.L. Page (U. Leicester),
A. Melandri (INAF-OAB), P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), D.N.
Burrows (PSU), A. Tohuvavohu (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 180718B (Crnogorcevic et al. GCN Circ.
22961), collecting 5.0 ks of Photon Counting (PC) mode data between
T0+38.9 ks and T0+50.6 ks. 

Four 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. The UVOT finds no new optical sources at the position of any
of the four X-ray sources. Details of these sources are given below:

Source 1:
  RA (J2000):  44.7960  =  02:59:11.03
  Dec (J2000): -31.6692  =  -31:40:09.2
  Error: 3.0 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (9.0 +/- 2.4)e-3 ct s^-1  
  Distance: 705 arcsec from Fermi/LAT position.
  Flux: (2.79 +/- 0.74)e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 2:
  RA (J2000):  44.6153  =  02:58:27.68
  Dec (J2000): -31.6555  =  -31:39:19.9
  Error: 6.1 arcsec (radius, 90% conf.)
  Count-rate: (1.91 [+0.92, -0.71])e-3 ct s^-1  
  Distance: 593 arcsec from Fermi/LAT position.
  Flux: (5.1 [+2.4, -1.9])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

Source 3:
  RA (J2000):  44.7970  =  02:59:11.27
  Dec (J2000): -31.4797  =  -31:28:47.0
  Error: 4.0 arcsec (radius, 90% conf. [Enhanced position])
  Count-rate: (2.80 [+1.14, -0.91])e-3 ct s^-1  
  Distance: 366 arcsec from Fermi/LAT position.
  Flux: (1.19 [+0.49, -0.39])e-13 erg cm^-2 s^-1 (observed, 0.3-10 keV)


Source 4:
  RA (J2000):  44.7053  =  02:58:49.28
  Dec (J2000): -31.4407  =  -31:26:26.5
  Error: 5.0 arcsec (radius, 90% conf.)
  Count-rate: (2.51 [+1.10, -0.87])e-3 ct s^-1  
  Distance: 227 arcsec from Fermi/LAT position.
  Flux: (5.1 [+2.2, -1.8])e-14 erg cm^-2 s^-1 (observed, 0.3-10 keV)

The results of the XRT-team automatic analysis of the XRT observations,
including a position-specific upper limit calculator, are available at
http://www.swift.ac.uk/ToO_GRBs/00020803.

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


GRB_name: GRB180722A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23032
SUBJECT: GRB 180722A: Swift-XRT observations
DATE:    18/07/24 14:33:45 GMT
FROM:    Boris Sbarufatti at PSU  <bxs60@psu.edu>

P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), B. Sbarufatti (INAF-OAB/PSU),
D.N. Burrows (PSU), A. Tohuvavohu (PSU), S.L. Gibson (U. Leicester), Z.
Liu (NAOC / U. Leicester), J.P. Osborne (U. Leicester), A. D'Ai
(INAF-IASFPA) 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 180722A (Shimomukai et al. GCN Circ. 23005) in a series of
observations tiled on the sky. The total exposure time is 1.2 ks,
distributed over 7 tiles; the maximum exposure at a single sky location
was 391 s. The data were collected between T0+45.7 ks and T0+47.1 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
~0.04 to ~0.12 ct s^-1, corresponding to a 0.3-10 keV observed flux of
1.8e-12 to 4.9e-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 http://www.swift.ac.uk/xrt_products/TILED_GRB00071.

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


GRB_name: GRB180720B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23033
SUBJECT: GRB 180720B: KAIT Optical Observations
DATE:    18/07/25 00:12:38 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, observed the field of Swift GRB 180720B
(Siegel et al., GCN 22973) each night from 21 to 24 UT, at a mean time
of 0.855, 1.886, 2.883 and 3.874 days, respectively, after the burst.
Observations were performed with a sequence in the B, V, R, I and
clear (roughly R) filters, and the exposure time was 60 s per image.
The optical afterglow (Martone et al., GCN 22976) was clearly detected
and we measure its clear band mag to be 18.5, 19.6, 20.5 and 20.9,
respectively, calibrated to the SDSS catalog.


GRB_name: GRB180721A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23034
SUBJECT: GRB 180721A: KAIT Optical Upper Limit
DATE:    18/07/25 00:13:00 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 Swift GRB 180721A (Sbarufatti et al.,
GCN 22994) starting at 11:25:23 UT, ~19 minutes after the burst.
Observations were performed with an automatic sequence in the
clear (roughly R), V, and I filters, and the exposure time was 20 s
per image. We do not detect any optical afterglow candidate within
the enhanced XRT position error circle (Goad et al., GCN 22997)
neither in single image, nor in the co-add images.
The typical limiting magnitude of our single clear image is about
19.5 mag calibrated to the Pan-STARRS1 catalog.


GRB_name: GRB180723A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23035
SUBJECT: GRB 180723A: Fermi GBM detection
DATE:    18/07/25 02:37:32 GMT
FROM:    Suraj Poolakkil at UAH  <sp0076@uah.edu>

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

"At 18:09:48.16 UT on 23 July 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180723A (trigger 554062193/ 180723757).

The on-ground calculated location, using the GBM trigger
data, is RA = 7.84, DEC = -66.11, with an uncertainty
of 1 degree (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 132 degrees.

The GBM light curve consists of a single bright peak
with a duration (T90) of about 19.71 s (50-300 keV).
The time-averaged spectrum from T0-2.05 s to T0+31.74 s is
best fit by a power-law function with an exponential
high-energy cutoff. The power law index is -1.22 +/- 0.02 and
the cutoff energy, parameterized as Epeak, is 178 +/- 5 keV.

The event fluence (10-1000 keV) in this time interval is
(4.616 +/- 0.057)E-05 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+3.39 s in the 10-1000 keV band
is 41.2 +/- 0.81 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB180720B
Detection_method: Fermi LAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23036
SUBJECT: GRB 180720B long follow up requested 
DATE:    18/07/25 08:52:55 GMT
FROM:    Arnon Dar at Technion-Israel Inst. of Tech  <arnon@physics.technion.ac.il>

Long follow up of the afterglow of the extremely bright GRB
180720B (Swift-BAT detection: Siegel et al., GCN #22973, GCN
#22975; Fermi-LAT detection: Bissaldi and Racusin, GCN #22980;
Fermi-GBM detection: Roberts et al., GCN #22981; Konus Wind
detection: Frederiks et al. GCN 23011) is urged. It will provide
another critical test of GRB theories. Its  current late-time X-ray
afterglow, measured with Swift XRT, decays like a single power-law
with a temporal index alpha=1.34+/-0.01 and an unabsorbed spectral
index beta=0.82+/-0.04 (Evans et al. Swift-XRT GRB lightcurve
repository). It satisfies well the Cannonball model closure relation
alpha=beta+1/2 (e.g., Dado and Dar, PhRvD, 94, 3007 (2016)) for
the late time unabsorbed afterglows of SN-GRBs (while those of
SN-less GRBs satisfy alpha=2,  e.g., Dado and Dar arXiv:1807.08726).
An SN akin to SN1998bw may be resolved from the optical afterglows
around day ~15. An achromatic break in the late time afterglow
is expected only if the host galaxy is aligned  near face on.

[GCN OPS NOTE(26jul18): The operator has corrected the GRB name 
in the Subject-line; and corrected Frederiks reference from 230110
to 23011.]


GRB_name: GRB180720B
Detection_method: Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23037
SUBJECT: GRB 180720B: AMI-LA 15.5 GHz observation
DATE:    18/07/25 09:12:00 GMT
FROM:    Itai Sfaradi at Hebrew U of Jerusalem  <itai.sfaradi@mail.huji.ac.il>

Itai Sfaradi (HUJI), Joe Bright (Oxford), Assaf Horesh (HUJI), Rob Fender
(Oxford) ,
Sara Motta (Oxford), David Titterington, Yvette Perrott (MRAO, Cambridge)
report:

We observed the position of GRB180720B (GCN CIRCULAR #22973) with the
Arcminute Microkelvin Imager Large Array (AMI-LA; Zwart et al. 2008; Hickish
et al. 2018) at 15.5 GHz on 2018-07-22.21 for 3.9 hours.
We clearly detect a source at the phase center, fitting the source with the
CASA task IMFIT
provides an integrated flux density of ~ 1 mJy and a position of RA:
00:02:07.02,
Dec: -02 55 02.224 with a synthesized beam major and minor FWHM of 93â€™â€™ and
27â€™â€™ respectively
(consistent with the position reported in GCN CIRCULAR #22973).

The custom pipeline REDUCE_DC (e.g. Perrott et al. 2015) was used to
calibrate
and flag the data, with 3C286 as the absolute flux calibrator and J2357-0152
as the interleaved phase calibrator.

We plan to continue monitoring this source, and would like to thank the
MRAO staff for carrying out these observations.


GRB_name: GRB180724A
Detection_method: Fermi GBM Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23038
SUBJECT: GRB 180724A: Insight-HXMT/HE detection
DATE:    18/07/26 03:16:41 GMT
FROM:    Zhengwei Li at IHEP  <lizw@ihep.ac.cn>

Y. Nang, C. K. Li., X. B. Li, J. Y. Liao, J. Guan, N. Sai, C. Wang, C. C. Guo, Y. Huang, G. Li, S. L. Xiong, 

C. Z. Liu, Z.W. Li, X. F. Li, Z. Chang, X. F. Lu, J. L. Zhao, A. M. Zhang, Y. F. Zhang, C. L. Zou (IHEP), 

Y. J. Jin, Z. Zhang (THU), T. P. Li (IHEP/THU), F. J. Lu, L. M. Song, H. Y. Wang, M. Wu, Y. P. Xu, S. N. Zhang (IHEP), 

report on behalf of the Insight-HXMT team:

 

At 2018-07-24T19:22:31.000 (T0), the Insight-HXMT/HE detected GRB 180724A in a routine search of the galactic 

plane survey data, which was also observed by Fermi/GBM (trigger number 554152956).

 

The Insight-HXMT/HE light curve mainly consists of a bright pulse followed by a tail with a duration (T90) of 

23.2 s measured from T0+1.6 s. The 1-second peak rate, measured from T0+3.7 s, is 1312.4 cnts/sec. The total 

counts from this burst is 15779.6 counts.




URL_LC:http://www.hxmt.org/images/GRB/HEB180724807_CsI_lc.jpg.




All measurements above are made with the CsI detectors operating in the low HV mode (previously called GRB mode) 

with the energy range of about 200-3000 keV (record energy). Only gamma-rays with energy greater than about 

200 keV can penetrate the spacecraft and produce signals in the CsI detectors installed inside of the telescope.

 

The NaI detectors also detected this pulse with a duration (T90) of 31.1 s from T0+1.6 s. The 1-second peak rate,

 measured from T0+7.8 s, is 239.3 cnts/sec. The total counts from this burst is 2859.7 counts. The energy range

 of NaI detectors are about 100-800 keV.

 

URL_LCï¼šhttp://www.hxmt.org/images/GRB/HEB180724807_NaI_lc.jpg

The analysis results presented above are preliminary; final results will be published elsewhere.




Insight-HXMT is the first Chinese space X-ray telescope, which was funded jointly by the China National Space 

Administration (CNSA) and the Chinese Academy of Sciences (CAS). More information about it could be found 

at: http://www.hxmt.org/index.php/enhome.


GRB_name: GRB180722B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23039
SUBJECT: GRB 180722B: Insight-HXMT/HE detection
DATE:    18/07/26 03:38:40 GMT
FROM:    Yue Huang at IHEP  <huangyue@ihep.ac.cn>

Y. Huang, G. Li, S. L. Xiong, X. B. Li, C. K. Li, C.Z. Liu, 
X.F. Li, Z. W. Li, Z. Chang, J. L. Zhao, A. M. Zhang, 
Y. F. Zhang, X. F. Lu, C. L. Zou (IHEP), Y. J. Jin, 
Z. Zhang (THU), T. P. Li (IHEP/THU),F. J. Lu, L. M. Song, 
H. Y. Wang, M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:
 
At 2018-07-22T23:49:13.000 (T0), the Insight-HXMT/HE detected
GRB 180722B(trigger ID: HEB180722992) in a routine search of the data,
which was also triggered by Fermi-GBM (trigger #553996158), 
Konus-Wind (trigger time 23:49:18.90 UT) and CALET 
(T. Tamura et al., GCN23028).
 
The Insight-HXMT/HE light curve consists of two broad pulses
with a duration (T90) of 49.2 s measured from T0+0.4 s.
The 1-s peak rate, measured from T0+41.5 s, is 1679.3 cnts/sec.
The total counts from this burst is 27707.0 counts.
 
URL_LC: http://www.hxmt.org/images/GRB/HEB180722992_lc.jpg
 
All measurements above are made with the CsI detectors operating in the
regular mode with the energy range of about 80-800 keV (record energy).
Only gamma-rays with energy greater than about 200 keV can penetrate
the spacecraft and leave signals in the CsI detectors installed inside
of the telescope.
 
The analysis results presented above are preliminary, 
final results will be published elsewhere.
  
Insight-HXMT is the first Chinese space X-ray telescope, which was funded
jointly by the China National Space Administration (CNSA) and the Chinese
Academy of Sciences (CAS). More information about it could be found at:
http://www.hxmt.org.


GRB_name: GRB180720B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23040
SUBJECT: GRB 180720B: OAJ optical observations
DATE:    18/07/26 08:56:58 GMT
FROM:    Luca Izzo at IAA-CSIC  <Luca.Izzo@ICRA.it>

L. Izzo, D. A. Kann (HETH/IAA-CSIC), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), C. C. Thoene, K. Bensch, M. Blazek (HETH/IAA-CSIC), M. C. Diaz-Martin, and S. Rodriguez-Llano (OAJ) report:

We observed the field of the Swift-BAT GRB 180720B (Siegel et al. GCN 22973), detected also by Fermi-LAT (Bissaldi et al. GCN 22980), with the 0.8m telescope of the Observatorio Astrofisico de Javalambre (Teruel, Spain). Observations consisted of a series of 3x300 s griz exposures, starting at 01:12:55 UT (10.85 hr after the GRB trigger). The afterglow is clearly detected at a position consistent with the one reported by Martone et al. (GCN 22976).

We measure a magnitude of r(AB) = 17.77+/- 0.05 mag at an average time of 01:37:14 UT (11.26 hr after the GRB trigger), as compared to nearby SDSS stars.


GRB_name: GRB180720B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23041
SUBJECT: NuSTAR observations of GRB 180720B
DATE:    18/07/26 16:39:39 GMT
FROM:    Eric C Bellm at UW  <ecbellm@uw.edu>

E. C. Bellm (UW) and S. B. Cenko (GSFC) report:

We have analyzed 38 ksec of NuSTAR data for GRB 180720B (M. H. Siegel et
al., GCN Circ. 22973), from 243 ksec to 318 ksec after the BAT trigger.
NuSTAR detects emission from the X-ray afterglow to approximately 30 keV.

The NuSTAR spectrum can be well-modeled from 3-30 keV by an absorbed power
law with spectral index 1.80+/-0.06, consistent with the value reported
by XRT (K.  L. Page et al., GCN Circ. 22984).  The 3-30 keV flux was
4.8+/-0.2 x 10^-12 erg cm^-2 s^-1.

We thank Karl Forster and the NuSTAR operations team for their assistance
executing these TOO observations.


GRB_name: GRB180720B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23042
SUBJECT: GRB 180720B: CALET Gamma-Ray Burst Monitor detection
DATE:    18/07/27 04:11:45 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

M. L. Cherry (LSU), A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita, Y. Kawakubo,
A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

The extremely bright, long GRB 180720B (Swift-BAT trigger #848890:
Siegel et al., GCN Circ. 22973, Barthelmy et al. GCN Circ. 22998;
Fermi-LAT detection: Bissaldi and Racusin, GCN Circ. 22980;
Fermi-GBM observation: Roberts and Meegan, GCN Circ. 22981;
MAXI/GGS detection: Negoro et al., GCN Circ. 22993;
Konus-Wind observation: Frederiks et al., GCN Circ. 23011)
triggered the CALET Gamma-ray Burst Monitor (CGBM)
at 14:21:40.948 UTC on 20 July 2018.  Because of a problem in
one of the ground alert processing script, the GCN notice was not
distributed automatically for this event.  The burst signal was seen
by all CGBM detectors.

The CGBM data cover the time interval from T-243 sec to T+1449 sec
(when the HV was on and the source was in the CGBM FoV).

The burst light curve shows the main emission episode comprised
of several bright overlapped pulses which starts
at T-2.9 sec, peaks at 15.3 sec, and ends at T+54.0 sec,
followed by the weak tail seen at least up to T+120.1 sec.
The T90 and the T50 durations measured by the SGM data are
51.1 +- 3.0 sec and 15.4 +- 1.4 sec (40-1000 keV), respectively.

No any precursor is seen in the time interval from T-243 sec to T-2.9 sec.

The time-averaged spectrum of the main episode (measured by the SGM
from T+0.8 sec to T+52.8 sec) is best fit in the 30 keV - 20 MeV range
by a GRB (Band) model with alpha = -1.29 +- 0.04,
Epeak =  686(-77, +88) keV, and beta = -2.23(-0.12, +0.09)
(chi2 = 254.4/236 dof).  The emission is seen up to ~20 MeV.
The resulting fluence in the 30 keV - 10 MeV range is
5.79(-0.19, +0.20)x10^-4 erg/cm2 .

Assuming a redshift of z=0.654 (Vreeswijk et al., GCN 22996)
and a FlatLambdaCDM cosmology with H0=68 km/s/Mpc and Omega_M=0.308
(Planck Collaboration 2016, A&A, 594, A13 (Paper XIII)),
the isotropic energy release, Eiso, is 6.82(-0.22, 0.24)x10^53 erg.

The quoted errors are at the 90% CL.

The ground processed light curve is available at

http://cgbm.calet.jp/cgbm_trigger/ground/1216131585/

All the quoted values are preliminary.

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


GRB_name: GRB180727A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23043
SUBJECT: GRB 180727A: Swift detection of a burst
DATE:    18/07/27 14:58:03 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

A. P. Beardmore (U Leicester), S. B. Cenko (GSFC),
P. A. Evans (U Leicester), A. Y. Lien (GSFC/UMBC),
F. E. Marshall (NASA/GSFC), K. L. Page (U Leicester),
D. M. Palmer (LANL), B. Sbarufatti (PSU), M. H. Siegel (PSU),
R. L. C. Starling (U Leicester) and A. Tohuvavohu (PSU) report on
behalf of the Neil Gehrels Swift Observatory Team:

At 14:15:28 UT, the Swift Burst Alert Telescope triggered
and located GRB180727A (Trigger #850231).  Due to a telemetry 
gap, very little BAT information is immediately available. 
The BAT light curve showed a single-peaked structure with 
a duration of about 1.5 sec.  The peak count rate
was ~5500 counts/sec (15-350 keV), at ~0 sec after the trigger. 
The burst does not seem to show significant emission above 100 keV. 
The full BAT information will be available after the 
next ground downlink. 

Using promptly downlinked data we find an uncatalogued X-ray source
located at RA, Dec 346.66536, -63.05052 which is equivalent to:
   RA(J2000)  = 23h 06m 39.69s
   Dec(J2000) = -63d 03' 01.9"
with an uncertainty of 3.7 arcseconds (radius, 90% containment). 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density in excess of the Galactic value (2.10 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 2.5
(+3.98/-2.45) x 10^21 cm^-2 (90% confidence). 

UVOT took a finding chart exposure of 150 seconds with the white
filter. 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 19.2 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 18.0 mag. No  correction has been made for the expected
extinction corresponding to E(B-V) of  0.02. 

We note this GRB was also detected by the GBM on Fermi, and their
automated light curve analysis indicates it is likely to be a short GRB. 

Burst Advocate for this burst is A. P. Beardmore (apb AT star.le.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB180727A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23044
SUBJECT: GRB 180727A: Fermi GBM observation
DATE:    18/07/27 19:30:47 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

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

"At 14:15:28.81 UT on 27 July 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180727A (trigger 554393733 / 180727594)
which was also detected by Swift (Beardmore et al., GCN 23043).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 46 degrees.

The GBM light curve consists of a single pulse
with a duration (T90) of about 1.1 s (50-300 keV).

The time-averaged spectrum from T0-0.19 s to T0+0.83 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is 0.14 +/- 0.28 and
the cutoff energy, parameterized as Epeak, is 69 +/- 4 keV.

The event fluence (10-1000 keV) in this time interval is
(3.32 +/- 0.18)E-7 erg/cm^2. The 64-msec peak photon flux measured
starting from T0+0.45 s in the 10-1000 keV band
is 7.2 +/- 1.2 ph/s/cm^2.


The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB180727A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23045
SUBJECT: GRB 180727A: Swift-XRT refined Analysis
DATE:    18/07/28 14:58:03 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

V. D'Elia (ASDC), D.N. Burrows (PSU), A. Tohuvavohu (PSU), S. J.
LaPorte (PSU), Z. Liu (NAOC / U. Leicester), J.P. Osborne (U.
Leicester), K.L. Page (U. Leicester), A. D'Ai (INAF-IASFPA), A.
Melandri (INAF-OAB) and A.P. Beardmore report on behalf of the
Swift-XRT team:

We have analysed 5.9 ks of XRT data for GRB 180727A (Beardmore et al.
GCN Circ. 23043), from 58 s to 80.1 ks after the  BAT trigger. The data
comprise 24 s in Windowed Timing (WT) mode (the first 7 s were taken
while Swift was slewing) with the remainder in Photon Counting (PC)
mode. Using 503 s of PC mode data and 2 UVOT images, we find an
enhanced XRT position (using the XRT-UVOT alignment and matching UVOT
field sources to the USNO-B1 catalogue): RA, Dec = 346.66632, -63.05183
which is equivalent to:

RA (J2000): 23h 06m 39.92s
Dec(J2000): -63d 03' 06.6"

with an uncertainty of 1.7 arcsec (radius, 90% confidence).

The light curve can be modelled with a power-law decay with a decay
index of alpha=2.4 (+0.3, -0.4).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.9 (+/-0.4). The
best-fitting absorption column is  2.1 (+1.8, -1.4) x 10^21 cm^-2, in
excess of the Galactic value of 2.1 x 10^20 cm^-2 (Willingale et al.
2013). The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.9 x 10^-11 (5.0 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      2.1 (+1.8, -1.4) x 10^21 cm^-2
Galactic foreground: 2.1 x 10^20 cm^-2
Excess significance: 2.2 sigma
Photon index:      1.9 (+/-0.4)

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00850231.

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


GRB_name: GRB180728A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23046
SUBJECT: GRB 180728A: Swift detection of a bright burst
DATE:    18/07/28 17:38:09 GMT
FROM:    David Palmer at LANL  <palmer@lanl.gov>

R. L. C. Starling (U Leicester), S. D. Barthelmy (GSFC),
A. Y. Lien (GSFC/UMBC), M. J. Moss (George Washington University),
K. L. Page (U Leicester) and D. M. Palmer (LANL) report on behalf of
the Neil Gehrels Swift Observatory Team:

At 17:29:00 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180728A (trigger=850471).  Swift did not slew immediately
due to the Earth limb constraint.  The BAT on-board calculated location is 
RA, Dec 253.569, -54.031 which is 
   RA(J2000) = 16h 54m 17s
   Dec(J2000) = -54d 01' 50"
with an uncertainty of 3 arcmin (radius, 90% containment, including 
systematic uncertainty).  The BAT light curve showed a small precursor
followed 10 seconds later by a bright FRED pulse of ~20 s duration. 
The peak count rate was ~100,000 counts/sec (15-350 keV), at ~13 sec 
after the trigger. 

Due to an observing constraint, Swift will not slew until T0+23.6
minutes. There will be no XRT or UVOT data until this time. 

Burst Advocate for this burst is R. L. C. Starling (rlcs1 AT star.le.ac.uk). 
Please contact the BA by email if you require additional information
regarding Swift followup of this burst. In extremely urgent cases, after
trying the Burst Advocate, you can contact the Swift PI by phone (see
Swift TOO web site for information: http://www.swift.psu.edu/too.html.)


GRB_name: GRB180727A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23047
SUBJECT: GRB 180727A: Swift-BAT refined analysis
DATE:    18/07/28 17:49:10 GMT
FROM:    Hans Krimm at NASA-GSFC/NSF  <hans.krimm@nasa.gov>

A. Y. Lien (GSFC/UMBC), S. D. Barthelmy (GSFC), A. P. Beardmore (U Leicester),
J. R. Cummings (CPI), H. A. Krimm (NSF/USRA), C. B. Markwardt (GSFC),
D. M. Palmer (LANL), T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):
  
Using the data set from T-239 to T+200 sec from the recent telemetry downlink,
we report further analysis of BAT GRB 180727A (trigger #850231)
(Beardmore et al., GCN Circ. 23043).  The BAT ground-calculated position is
RA, Dec = 346.639, -63.066 deg which is
    RA(J2000)  =  23h 06m 33.3s
    Dec(J2000) = -63d 03' 57.9"
with an uncertainty of 1.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 85%.
  
The mask-weighted light curve shows a single peak of duration ~1 second,
peaking at T+0 sec. T90 (15-350 keV) is 1.1 +- 0.2 sec (estimated error
including systematics).
  
The time-averaged spectrum from T-0.1 to T+1.3 sec is best fit by a power law
with an exponential cutoff.  This fit gives a photon index 0.59 +- 0.51,
and Epeak of 67.6 +- 14.8 keV (chi squared 43.23 for 56 d.o.f.).  For this
model the total fluence in the 15-150 keV band is 2.7 +- 0.2 x 10^-7  erg/cm2
and the 1-sec peak flux measured from T-0.05 sec in the 15-150 keV band is
3.6 +- 0.2 ph/cm2/sec.  A fit to a simple power law gives a photon index
of 1.60 +- 0.11 (chi squared 57.46 for 57 d.o.f.).  All the quoted errors
are at the 90% confidence level.
  
The duration and hardness of this burst are consistent with the general
BAT short GRB distribution.

The results of the batgrbpoduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/850231/BA/


GRB_name: GRB180728A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23048
SUBJECT: GRB 180728A: MASTER  OT (= new object) detection 
DATE:    18/07/28 18:33:41 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, N.Tiurina, D.Vlasenko, V.Kornilov, A.Kuznetsov, 
V.Chazov, I.  Gorbunov, D.Zimnukhov, D.Kuvshinov, P.Balanutsa,
V.Vladimirov,
Lomonosov Moscow State University,SAI

D. Buckley,
South African Astronomical Observatory (SAAO)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias (IAC)

A. Tlatov, V.Senik, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

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

H.Levato,
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University (ISU)

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

MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru, 
Lipunov et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in 
South Africa (South African Astronomical Observatory) was pointed to the 
GRB180728A 22 sec after notice time and 38 sec after trigger time at 
2018-07-28 17:29:38 UT in two polarizations. On our first (10s exposure) 
set we  found  new optical object (transient) within SWIFT error-box 
(ra=253.567 dec=-54.0308  r=0.05) :

MASTER OT J165415.75 -540239.27
RA, DEC = 16h 54m 15.75s , -54d 02m 39.27s
m ~ 14.5

We  see a surprising automatic light curve  when the source has 
risen to constant magnitude during first ~30 minutes!

The observations made on zenit distance = 28 degrees, galaxy latitude b = 
-7 degree.
The moon (99 % bright part) is 11 degrees above the horizon. The distance 
between  moon and  object is 61
The sun  altitude  is -19.8 degree.
The object can be observed till 2018-07-29 05:17:09

The message may be cited.


GRB_name: GRB180728A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23049
SUBJECT: GRB 180728A: Swift-XRT observations
DATE:    18/07/28 19:29:20 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

M. Perri (ASDC), P.A. Evans (U. Leicester), J.P. Osborne (U.
Leicester), D.N. Burrows (PSU), J.A. Kennea (PSU) and G. Cusumano
(INAF-IASF PA) report on behalf of the Swift-XRT team:

The XRT began observing the field of GRB 180728A at 17:57:51.5 UT,
1730.8 seconds after the BAT trigger. XRT found a bright, uncatalogued
X-ray source located at RA, Dec 253.5648, -54.0437 which is equivalent
to:
   RA(J2000)  = +16h 54m 15.55s
   Dec(J2000) = -54d 02' 37.3"
with an uncertainty of 5.8 arcseconds (radius, 90% containment). This
location is 46 arcseconds from the BAT onboard position, within the BAT
error circle. No event data are yet available to determine the column
density using X-ray spectroscopy.

The initial flux in the 2.5 s image was 7.92e-10 erg cm^-2 s^-1 (0.2-10
keV).


GRB_name: GRB180728A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23050
SUBJECT: GRB 180728A: MASTER OT J165415.75-540239.27 is the Optical Counterpart of GRB
DATE:    18/07/28 19:35:21 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, N.Tiurina, D.Vlasenko, V.Kornilov, A.Kuznetsov, 
V.Chazov, I.  Gorbunov, D.Zimnukhov, D.Kuvshinov, P.Balanutsa,
V.Vladimirov,
Lomonosov Moscow State University,SAI

D. Buckley,
South African Astronomical Observatory (SAAO)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias (IAC)

A. Tlatov, V.Senik, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

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

H.Levato,
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University (ISU)

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

MASTER-SAAO robotic telescope (MASTER-Net: http://observ.pereplet.ru, Lipunov 
et al., 2010, Advances in Astronomy, vol. 2010, 30L) located in South Africa 
(South African Astronomical Observatory) was detected new optical 
object (Lipunov et al., GCN Circ #23048) MASTER OT J165415.75-540239.27
at Swift XRT position (Starling et al., GCN
#23046; Perri et al., GCN #23049;):

RA, DEC = 16h 54m 15.75s , -54d 02m 39.27s
Error ~1 arcsec

We see a gradual attenuation of the OT on an automatic light 
curve. Thus, the transient is an optical counterpart of the gamma-ray 
burst GRB 180728A.

The automatic light curve is available at 
http://observ.pereplet.ru/images/MASTER_OT_J165415.75-540239.27.jpg


The message may be cited.


GRB_name: GRB180728A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23051
SUBJECT: GRB 180728A: Enhanced Swift-XRT position
DATE:    18/07/28 23:41:08 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 1791 s of XRT Photon Counting mode data and 2 UVOT
images for GRB 180728A, 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 = 253.56514, -54.04454 which is equivalent
to:

RA (J2000): 16h 54m 15.63s
Dec (J2000): -54d 02' 40.3"

with an uncertainty of 1.5 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: GRB180728A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23052
SUBJECT: GRB 180728A: Swift-XRT refined Analysis
DATE:    18/07/29 03:31:35 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

A. Tohuvavohu (PSU), S. J. LaPorte (PSU), J.A. Kennea (PSU), J.P.
Osborne (U. Leicester), K.L. Page (U. Leicester), A.P. Beardmore (U.
Leicester), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), P. D'Avanzo
(INAF-OAB) and R.L.C. Starling report on behalf of the Swift-XRT team:

We have analysed 7.2 ks of XRT data for GRB 180728A (Starling et al.
GCN Circ. 23046), from 1.7 ks to 26.6 ks after the  BAT trigger. The
data comprise 1.9 ks in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Osborne et al. (GCN Circ. 23051).

The light curve can be modelled with a series of power-law decays. The
initial decay index is alpha=0.56 (+/-0.05). At T+5559 s  the decay
steepens to an alpha of 1.49 (+0.29, -0.14) before breaking again at
T+14.6 ks to a final decay with index alpha=0.58 (+0.23, -2.08).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.886 (+0.020, -0.017). The
best-fitting absorption column is  consistent with the Galactic value
of 3.2 x 10^21 cm^-2 (Willingale et al. 2013). The PC mode spectrum has
a photon index of 1.75 (+/-0.09) and a best-fitting absorption column
of 3.8 (+/-0.5) x 10^21 cm^-2. The counts to observed (unabsorbed)
0.3-10 keV flux conversion factor deduced from this spectrum  is 4.5 x
10^-11 (6.2 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      3.8 (+/-0.5) x 10^21 cm^-2
Galactic foreground: 3.2 x 10^21 cm^-2
Excess significance: 2.2 sigma
Photon index:      1.75 (+/-0.09)

If the light curve continues to decay with a power-law decay index of
0.58, the count rate at T+24 hours will be 0.65 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 3.0 x
10^-11 (4.0 x 10^-11) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00850471.

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


GRB_name: GRB180728A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23053
SUBJECT: GRB 180728A: Fermi GBM observation
DATE:    18/07/29 04:18:59 GMT
FROM:    Peter Veres at UAH  <veresp@gmail.com>

P. Veres, C. Meegan, and B. Mailyan (all UAH)
report on behalf of the Fermi GBM Team:

"At 17:29:02.28 UT on 28 July 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180728A (trigger 554491747 / 180728728)
which was also detected by the Swift/BAT (Starling et al., GCN 23046).
The GBM on-ground location is consistent with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 35 degrees.

The GBM light curve consists of a precursor and a very bright peak
with a duration (T90) of about 6.4 s (50-300 keV).
The time-averaged spectrum from T0+9.2s to T0+23.6 s is
best fit by a Band function with Epeak = 79.2 +/- 1.4 keV,
alpha = -1.54 +/- 0.01, and beta = -2.46 +/- 0.02.

The event fluence (10-1000 keV) in this time interval is
(5.65 +/- 0.02)E-5 erg/cm^2. The 1-sec peak photon flux measured
starting from T0+11.1 s in the 10-1000 keV band
is 231.0 +/- 1.2 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."

[GCN OPS NOTE(29jul18):  As pointed out by A.Kann, the "170728A"
in the Subject-line was corrected to "180728A".]


GRB_name: GRB180728A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23054
SUBJECT: GRB 180728A: Swift-BAT refined analysis
DATE:    18/07/29 16:17:30 GMT
FROM:    Hans Krimm at NASA-GSFC/NSF  <hans.krimm@nasa.gov>

C. B. Markwardt (GSFC), S. D. Barthelmy (GSFC),  J. R. Cummings (CPI),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC), D. M. Palmer (LANL),
T. Sakamoto (AGU), M. Stamatikos (OSU), R. L. C. Starling (U Leicester),
T. N. Ukwatta (LANL) (i.e. the Swift-BAT team):

Using the data set from T-239 to T+667 sec from the recent telemetry 
downlink,
we report further analysis of BAT GRB 180728A (trigger #850471)
(Starling, et al., GCN Circ. 23046).  The BAT ground-calculated position is
RA, Dec = 253.574, -54.037 deg which is
    RA(J2000)  =  16h 54m 17.7s
    Dec(J2000) = -54d 02' 13.7"
with an uncertainty of 1.0 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 57%.

The mask-weighted light curve shows a relatively faint, soft precursor 
near the
trigger time, lasting about 3 seconds.  This was followed by a single, much
brighter pulse, which consisted of two overlapping peaks.   This pulse 
began at
T+11 sec, peaked at T+13 sec, and faded to background by T+40 sec.
T90 (15-350 keV) is 8.68 +- 0.30 sec (estimated error including 
systematics).

The time-averaged spectrum from T-0.24 to T+36.51 sec is best fit by a 
simple
power-law model.  The power law index of the time-averaged spectrum is
1.97 +- 0.03.  The fluence in the 15-150 keV band is 2.96 +- 0.06 x 
10^-5 erg/cm2.
The 1-sec peak photon flux measured from T+12.61 sec in the 15-150 keV band
is 132.0 +- 2.9 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/850471/BA/


GRB_name: GRB180728A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23055
SUBJECT: GRB 180728A: VLT/X-shooter redshift of a nearby energetic GRB
DATE:    18/07/29 18:23:26 GMT
FROM:    Daniel Perley at Liverpool JMU  <d.a.perley@ljmu.ac.uk>

A. Rossi (INAF-OAS), L. Izzo (HETH/IAA-CSIC), B. Milvang-Jensen
(DAWN/NBI), D. A. Perley (LJMU), A. de Ugarte Postigo (HETH/IAA-CSIC and
DARK/NBI), D. A. Kann (HETH/IAA-CSIC), A. J. Levan (U. Warwick), N. R.
Tanvir (U. Leicester), S. Covino (INAF/Brera), and D. B. Malesani
(DAWN/NBI and DARK/NBI) report on behalf of the Stargate collaboration:

We observed the optical counterpart of GRB 180728A (Starling et al., GCN
23046; Lipunov et al., GCN 23048) with the ESO VLT UT2 equipped with the
X-shooter spectrograph.  One 600 s spectrum was taken during evening
twilight on 2018 July 28 beginning at 23:13 UT, plus two additional 600
s spectra on 2018 July 29 beginning at 05:10 UT.  The spectra cover a
wavelength range from 3000-25000 AA.

A red continuum is detected across the spectral range. We detect
absorption features due to Mg II (3124,3132), Mg I (3187), and Ca II
(4395,4434) at a consistent redshift of z=0.117, which we propose as the
redshift of the GRB.  Galactic ISM absorption features of Ca II and Na I
are also detected.

This GRB resembles the famous GRB 030329, but slightly less energetic
(E_iso = 2e+51 erg given the fluence value provided by Veres et al., GCN
23053).  It is the closest energetic (E_iso > 1e+51 erg) GRB with a
measured redshift to date.

We note that although Galactic extinction in this direction is
significant (A_V = 0.763; Schlafly et al. 2011, ApJ 737:103) a campaign
to study the anticipated associated supernova should still be practical
with moderate-aperture telescopes at this redshift.

We acknowledge the ESO observing staff at Paranal, in particular Pascale
Hibon and R. Thomas.

________________________________
Important Notice: the information in this email and any attachments is for the sole use of the intended recipient(s). If you are not an intended recipient, or a person responsible for delivering it to an intended recipient, you should delete it from your system immediately without disclosing its contents elsewhere and advise the sender by returning the email or by telephoning a number contained in the body of the email. No responsibility is accepted for loss or damage arising from viruses or changes made to this message after it was sent. The views contained in this email are those of the author and not necessarily those of Liverpool John Moores University.


GRB_name: GRB180728B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23056
SUBJECT: IPN Triangulation of GRB 180728B (short)
DATE:    18/07/29 19:48:50 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks, A. Kozlova,
and T. Cline on behalf of the Konus-Wind team,

K. Hurley, on behalf of the IPN,

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

A. von Kienlin, X. Zhang, A. Rau, V. Savchenko, E. Bozzo,
and C. Ferrigno, on behalf of the INTEGRAL SPI-ACS GRB team,

and

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

The short-duration GRB 180728B was detected by
Fermi (GBM; trigger 554505003), INTEGRAL (SPI-ACS), Konus-Wind,
and Swift (BAT), at about 76199 s UT (21:09:59).
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:
   222.078 (14h 48m 19s) +15.942 (+15d 56' 32")
  Corners:
   221.253 (14h 45m 01s) +11.625 (+11d 37' 29")
   221.537 (14h 46m 09s) +11.383 (+11d 23' 00")
   222.836 (14h 51m 21s) +20.467 (+20d 28' 01")
   222.533 (14h 50m 08s) +20.757 (+20d 45' 26")
  ---------------------------------------------
The error box area is 2.88 sq. deg, and its maximum
dimension is 9.423 deg (the minimum one is 18.8 arcmin).
The Sun distance was 88 deg.

This box may be improved.

A triangulation map is posted at
http://www.ioffe.ru/LEA/GRBs/GRB180728_T76197/IPN

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


GRB_name: GRB180728B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23057
SUBJECT: GRB 180728B: Fermi GBM detection
DATE:    18/07/30 03:29:50 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

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

"At 21:09:58.91 UT on 28 July 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180728B (trigger 554505003 / 180728882).
which was also localized by IPN (GCN 23056).

The angle from the Fermi LAT boresight at the GBM trigger time is 96
degrees.

The GBM light curve shows a structured spike
with a duration (T90) of about 0.6 s (50-300 keV).
The time-averaged spectrum from T0-0.06 s to T0+0.38 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.18 +/- 0.15 and
the cutoff energy, parameterized as Epeak, is 504 +/- 61 keV.

The event fluence (10-1000 keV) in this time interval is
(1.36 +/- 0.90)E-06 erg/cm^2. The 64-ms peak photon flux measured
starting from T0+0.19 s in the 10-1000 keV band
is 16.5 +/- 1.7 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB180703B
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23058
SUBJECT: GRB 180703B: CALET CAL gamma-ray analysis
DATE:    18/07/30 09:44:28 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

K. Yoshikawa, Y. Asaoka (Waseda U), N. Cannady (LSU),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita, Y. Kawakubo,
A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

Using the CALET CALorimeter (CAL) data, we report GeV gamma-ray search
analysis associated to GRB 180703B (Racusin et al. GCN Circ. 22884;
Takahashi et al. GCN Circ. 22888; Poolakkil and Meegan GCN Circ. 22897;
Hurley et al. GCN Circ. 22908; Frederiks et al. GCN Circ. 22914).

The CAL was operating in low energy trigger mode at the trigger time of
the CALET Gamma-ray Burst Monitor (CGBM).  We have searched for
gamma-ray events in the 1-10 GeV band from -60 sec to +60 sec from
the CGBM trigger time using the Fermi-LAT position (Racusin et al.
GCN Circ. 22884) and found no candidates.  The 90% upper limit of CAL is
1.5e-6 erg/cm2/s (1-10 GeV) assuming a power-law spectrum of a photon
index of -2.

All the quoted values are preliminary.


GRB_name: GRB180715A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23059
SUBJECT: GRB 180715A: CALET CAL gamma-ray analysis
DATE:    18/07/30 09:50:27 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

N. Cannady (LSU), K. Yoshikawa, Y. Asaoka (Waseda U),
A. Yoshida, T. Sakamoto, V. Pal'shin, S. Sugita, Y. Kawakubo,
A. Tezuka, S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

Using the CALET CALorimeter (CAL) data, we report GeV gamma-ray search
analysis associated to GRB 180715A (Ukwatta, et al., GCN Circ. 22947, 22951;
Hamburg and Meegan, GCN Circ. 22952; Torii et al., GCN Circ. 22956)

The CAL was operating in low energy trigger mode at the trigger time of
the CALET Gamma-ray Burst Monitor (CGBM).  We have searched for
gamma-ray events in the 1-10 GeV band from -60 sec to +60 sec from
the CGBM trigger time using the Swift-BAT position (Ukwatta et al.
GCN Circ. 22951) and found no candidates.  The 90% upper limit of CAL is
3.2e-7 erg/cm2/s (1-10 GeV) assuming a power-law spectrum of a photon
index of -2.

All the quoted values are preliminary.


GRB_name: GRB180728B
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23060
SUBJECT: Konus-Wind observation of GRB 180728B
DATE:    18/07/30 12:14:01 GMT
FROM:    Dmitry Svinkin at Ioffe Institute  <svinkin@mail.ioffe.ru>

D. Svinkin, S. Golenetskii, R. Aptekar, D. Frederiks,
M. Ulanov, A. Tsvetkova, A. Lysenko, A.Kozlova, and T. Cline
on behalf of the Konus-Wind team, report:

The short-duration GRB 180728B
(IPN triangulation Svinkin et al., GCN Circ. 23056)
triggered Konus-Wind at T0=76197.29 s UT (21:09:57.290).

The burst light curve shows a multi-peaked structure
which starts at ~T0-0.2 s and has a total duration of ~0.4 s.
The emission is seen up to ~5 MeV.

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB180728_T76197/

As observed by Konus-Wind, the burst
had a fluence of 1.35(-0.22,+0.25)x10^-6 erg/cm2,
and a 16-ms peak flux, measured from T0-0.004 s,
of 9.59(-3.38,+3.55)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+0.192 s)
is best fit in the 20 keV - 10 MeV range
by a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with  alpha = 0.25(-0.61,+0.88)
and Ep = 404(-74,+118) keV (chi2 = 15/17 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 = 15/16 dof).

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


GRB_name: GRB180728A
Detection_method: Konus-Wind Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23061
SUBJECT: Konus-Wind observation of the bright nearby GRB 180728A
DATE:    18/07/30 12:21:03 GMT
FROM:    Dmitry Frederiks at Ioffe Institute  <fred@mail.ioffe.ru>

D. Frederiks, S. Golenetskii, R.Aptekar, A. Kozlova,
A.Lysenko,  D. Svinkin, A. Tsvetkova,  M. Ulanov, and T. Cline,
on behalf of the Konus-Wind team, report:

The long, very bright GRB 180728A
(Swift-BAT detection: Starling et al., GCN 23046;
Fermi-GBM detection: Veres et al., GCN 23053)
triggered Konus-Wind (KW) at T0=62954.093 s UT (17:29:14.093).

The burst light curve shows a smooth pulse with a total duration
(T100) of ~17 s. The emission is seen up to ~10 MeV.

As observed by Konus-Wind, the burst had a fluence of
(5.14 Â± 0.29)x10^-5 erg/cm2 and a 64-ms peak energy flux,
measured from T0+15.168, of (1.94 Â± 0.15)x10^-5 erg/cm2
(both in the 20 keV - 10 MeV energy range).

The time-integrated spectrum (measured from T0 to T0+19.2 s)
is best fit in the 30 keV - 15 MeV range
by the GRB (Band) function with the following model parameters:
the low-energy photon index alpha = -1.48 (-0.10,+0.12),
the high energy photon index beta = -2.57 (-0.18,+0.12),
the peak energy Ep = 97 (-6,+7) keV,
chi2 = 94/96 dof.

The spectrum near the peak count rate (measured from T0+1.280 s
to T0+1.792 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 = -1.44 (-0.15,+0.15),
the high energy photon index beta = -2.81 (-1.44,+0.24),
the peak energy Ep = 127 (-13,+18) keV,
chi2 = 54/56 dof.

Assuming the redshift z=0.117 (Rossi et al., GCN 23055)
and a standard cosmology with H_0 = 67.3 km/s/Mpc, Omega_M = 0.315,
and Omega_Lambda = 0.685 (Planck Collaboration, 2014),
we estimate the following rest-frame parameters:
the isotropic energy release E_iso is (2.33 Â± 0.10)x10^51 erg,
the peak luminosity L_iso is (9.51 Â± 0.58)x10^50 erg/s
(both in the 1-10000 keV rest-frame band).
The rest-frame peak energy of the time-integrated spectrum,
Epi,z, is 108(-7, 8) keV, and the rest-frame peak energy of
the 'peak' spectrum, Epp,z, is 142(-15, 20) keV.
With these energetics, the burst lies on the upper
edges of 68% prediction bands for both 'Amati' and 'Yonetoku'
relations built for the sample of 138 long KW GRBs with known
redshifts (Tsvetkova et al., ApJ 850 161, 2017).

The Konus-Wind light curve of this GRB is available at
http://www.ioffe.ru/LEA/GRBs/GRB180728_T62954/

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


GRB_name: GRB180727A
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23062
SUBJECT: GRB 180727A: Swift/UVOT Upper Limits
DATE:    18/07/30 18:03:24 GMT
FROM:    Frank Marshall at Swift/UVOT  <marshall@milkyway.gsfc.nasa.gov>

F. E. Marshall (NASA/GSFC) and A. Beardmore (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180727A
77 s after the BAT trigger (Beardmore et al., GCN Circ. 23043).
No optical afterglow consistent with the enhanced XRT position
(D'Elia et al., GCN Circ. 23045)
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            77          227          147         >20.9
u_FC               290          303           12         >18.4
white             4280         5915          393         >21.7
v                 4690         6312          379         >19.6
b                 4075         5710          393         >21.2
u                 5305         5505          197         >20.3
uvw1              5101         5301          197         >20.0
uvm2              4895         5095          197         >21.0
uvw2              4485         6122          393         >21.4

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.02 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB180701A
Detection_method: CALET
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23063
SUBJECT: GRB 180701A/MAXI J2119-045: CALET Gamma-Ray Burst Monitor data search
DATE:    18/07/31 03:04:31 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

V. Pal'shin, Y. Kawakubo, T. Sakamoto, A. Yoshida, S. Sugita, A. Tezuka,
S. Matsukawa, H. Onozawa, T. Ito, H. Morita, Y. Sone (AGU),
K. Yamaoka (Nagoya U), S. Nakahira (RIKEN), I. Takahashi (IPMU),
Y. Asaoka, S. Ozawa, S. Torii (Waseda U), Y. Shimizu, T. Tamura (Kanagawa U),
W. Ishizaki (ICRR), M. L. Cherry (LSU), S. Ricciarini (U of Florence),
A. V. Penacchioni, P. S. Marrocchesi (U of Siena)
and the CALET collaboration:

We have performed a search of hard X-ray/gamma-ray emission
from GRB 180701A/MAXI J2119-045 (Maruyama et al., GCN Circ. 22880)
in the CALET Gamma-ray Burst Monitor (CGBM) data around
the MAXI trigger time at T0=06:47 UT on 2018 July 1.

The source position (RA, Dec (J2000) = 319.919 deg, -4.500 deg)
at the trigger time was in the CGBM FOV at favorable angles (the off-axis
angles 22.1 deg and 12.2 deg for HXM and SGM detector respectively).

No CGBM on-board trigger occurred around T0.
By using the CGBM time-history data (0.125 sec time resolution),
we found no statistically significant signal between +-50 sec from T0.
We estimate 7-sigma upper limit in the 30-1000 keV band as
6x10^-7 erg/cm2/s assuming a power law with exponential cutoff model:
dN/dE ~ (E^alpha)*exp(-E*(2+alpha)/Ep)
with alpha = -1.0 and Ep = 200 keV in 1 s exposure.

At the time of the Konus-Wind event at 06:37:44 UTC (=T0-556 sec)
suggested to be the main part of GRB 180701A (Kozlova et al.,
GCN Circ. 22915), the position of the MAXI source was in the CGBM FoV
at favorable angles (the off-axis angles 44.9 deg and 40.4 deg
for HXM and SGM detector respectively).
For the reported Konus-Wind spectral parameters, the estimated response
in the CGBM detectors for the MAXI position would have a signal-to-noise
ratio up to 15 in individual TH channel and up to 18 in combination
of channels, while we do not see any hint of emission around this time.
Hence, we conclude that the Konus-Wind event is likely not related
to GRB 180701A/MAXI J2119-045.

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


GRB_name: GRB180728A
Detection_method: Swift-UVOT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23064
SUBJECT: GRB 180728A: Swift/UVOT Detection
DATE:    18/07/31 03:04:49 GMT
FROM:    Sam LaPorte at PSU  <sjl5346@psu.edu>

GRB 180728A: Swift/UVOT Detection

S. J. LaPorte (PSU) and R. L. C. Starling (U. Leicester)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of GRB 180728A
1740 s after the BAT trigger (Starling et al., GCN Circ. 23046).
A source consistent with the enhanced XRT position
(Osborne et al. GCN Circ. 23051)
is detected in the initial UVOT exposures.

The preliminary UVOT position is:
    RA  (J2000) =  16:54:15.53 =  253.56472 (deg.)
    Dec (J2000) = -54:02:40.2 =  -54.04451 (deg.)
with an estimated uncertainty of 0.43 arc sec. (radius, 90% confidence),
consistent with MASTER OT J165415.75-540239.27 (Lipunov et al., GCN #23050).

Preliminary detections 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             1740         1890          147         16.25 +/- 0.03
white             7713         15148         465         17.28 +/- 0.03 
v                 1897         1917           20         16.07 +/- 0.14
b                 1995         2013           18         16.58 +/- 0.10
u                 1970         1990           20         15.93 +/- 0.10
w1                1946         1966           20         16.20 +/- 0.17
m2                1921         2114           39         16.60 +/- 0.18
w2                2045         2065           19         16.37 +/- 0.19

The magnitudes in the table are not corrected for the Galactic extinction
due to the reddening of E(B-V) = 0.29 in the direction of the burst
(Schlegel et al. 1998).


GRB_name: GRB180728B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23065
SUBJECT: GRB 180728B: MASTER optical observations short GRB IPN error box 
DATE:    18/07/31 06:56:36 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, E. Gorbovskoy, P.Balanutsa, N.Tiurina, D.Vlasenko, V.Kornilov, 
A.Kuznetsov,  V.Chazov, I.  Gorbunov, D.Zimnukhov, D.Kuvshinov, 
V.Vladimirov,
Lomonosov Moscow State University,SAI

D.Svinkin (Ioffe Institute, StPetersburg, Russia)

D. Buckley,
South African Astronomical Observatory (SAAO)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias (IAC)

A. Tlatov, V.Senik, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

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

H.Levato,
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University (ISU)

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

MASTER-SAAO  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in SAAO was starting survey on the IPN  GRB180728B error-box 
(Svinkin et al., GCN Circ #23056; Hamburg et al., GCN Circ #23057)  14269 
sec after notice time and 70698 
sec after trigger time at 2018-07-29 16:48:15 UT. The 5-sigma upper limit 
on our first (180s exposure)  set is about 18mag.

The typical limit of coadded images is about 20 mag.
We marginally found one candidate to uncataloged object source near 
PGC052927 galaxy:

MASTER OT J144922.8+164418.2

RA,DEC = 14h 49m 22.8s +16d 44' 18.2"    error = 0.7 arcsec
mag = 19.7;
The offset from galaxy is 10.8W and 22.2N arcsec.

====================================================================

The observations made on zenit distance = 50 degrees, galactic latitude b 
=  61 degree.
The moon (97 % bright part) below the horizon (The altitude of the Moon is 
-8 deg.
Observations started at twilight.
The sun  altitude  is -11.1 deg.
The object can be observed till sunrise at 2018-07-30 05:26:48.


The covered map is available at
http://master.sai.msu.ru/static//IPN/db/GRB180728.88/img/ligo_master_2018-07-30-16-09-11.eb.zoom.1.png


We reobserved possible transient on the next night starting 2018-07-30
16:57:46 UT. We do not find the
object brighter than  20.5 .


GRB_name: GRB180728A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23066
SUBJECT: GRB 180728A: A long GRB of the X-ray flash (XRF) subclass, expecting supernova appearance
DATE:    18/07/31 10:29:39 GMT
FROM:    Remo Rufinni at ICRA  <ruffini@icra.it>

R. Ruffini, Y. Aimuratov, C. L. Bianco, Y. C. Chen, D. M. Fuksman, M. Karlica, R. Moradi, D. Primorac, J.A. Rueda, N. Sahakyan, Y. Wang, on behalf of the ICRANet team, report:

GRB 180728A has T90=6.4s (P. Veres et al., GCN 23053), peak energy 142 (-15.+20) keV, and isotropic energy (2.33 +/- 0.10)x10^51 erg (D. Frederiks, et al., GCN 23061). It presents the typical characteristic of a subclass of long GRBs called X-ray flashes (XRFs, see Ruffini et al., ApJ 832 (2016) 136), originating from a tight binary of a FeCO Core undergoing a supernova explosion in presence of a companion neutron star (NS) which undergoes hypercritical accretion. The outcome (see Fig. [1]) is a new binary composed by a more massive NS (MNS) and a newly born NS (vNS). Using the averaged observed value (Cano et al., 2016), and considering the redshift z=0.117 (A. Rossi et al., GCN 23055), a bright optical signal will peak at 14.7 +/- 2.9 days after the trigger (12 August 2018, uncertainty from August 9th to August 15th) at the location of RA 253.56472 and DEC -54.04451, with an uncertainty 0.43 arc sec (S. J. LaPorte et al., GCN 23064). The follow-up observations, especially the optical bands for the SN, as well as attention to binary NS pulsar behaviors in the X-ray afterglow emission, are recommended.


[1] Link: http://www.icranet.org/documents/180728A_f1.png

Figure Caption: Snapshot of the binary system formed by the MNS and by the vNS together with the SN ejecta density. See for details Fig. 7 of Ruffini et al., ApJ 832 (2016) 136.


GRB_name: GRB180728A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23067
SUBJECT: GRB 180728A: No evidence of SN in early VLT/X-shooter spectra
DATE:    18/07/31 12:46:56 GMT
FROM:    Kasper Elm Heintz at Univ. of Iceland and DAWN/NBI  <keh14@hi.is>

K. E. Heintz (Univ. Iceland and DAWN/NBI), L. Izzo (HETH/IAA-CSIC), A. Rossi (INAF-OAS), A. de Ugarte Postigo (HETH/IAA-CSIC, DARK/NBI), D. B. Malesani (DAWN/NBI, DARK/NBI), D. A. Perley (LJMU), C. C. Thoene (HETH/IAA-CSIC), J. P. U. Fynbo (DAWN/NBI), B. Milvang-Jensen (DAWN/NBI), D. A. Kann (HETH/IAA-CSIC), N. R. Tanvir (U. Leicester), A. J. Levan (U. Warwick), S. Schulze (Weizmann), and G. Pugliese (API/U. Amsterdam) report on behalf of the Stargate collaboration;

We observed again the optical afterglow of the bright, low-redshift GRB 180728A (Starling et al., GCN 23046; Lipunov et al., GCB 23048; Rossi et al., GCB 23055) with the ESO VLT UT2 equipped with the X-shooter spectrograph. Observations were carried out around July 30.21 UT (35.5 hr after the GRB).

In our observations, the afterglow has faded significantly compared to our previous observation (Rossi et al., GCN 23055), reaching a magnitude of R ~ 20 (Vega). Continuum is detected across the whole observed range 3000-25000 AA, despite at lower S/N. Weak emission lines from a faint host are now visible, corresponding to Halpha, Hbeta, [N II], [O III] 5008 at the GRB redshift. The small Balmer decrement is consistent with negligible dust extinction in the host galaxy.

After excluding the host emission lines and correcting for Galactic extinction, the observed continuum can be fit with a single power-law with spectral index ~ 0.6 (F_nu~nu^-beta). In particular, we do not see evidence in any of our spectra for broad undulations or deviations from a power-law behavior as reported by Buckley et al. (ATel 11897).
A figure showing our spectrum can be seen at:
https://www.astro.ku.dk/~malesani/GRB/180728A/GRB180728A_spec.png

We acknowledge expert support from the ESO observing staff in Paranal,
in particular Pascale Hibon, Bin Yang, and Romain Thomas.


GRB_name: GRB180728B
Detection_method: IPN Triangulation
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23069
SUBJECT: GRB 180728B: GOTO optical search over IPN region
DATE:    18/07/31 21:56:14 GMT
FROM:    Danny Steeghs at U.of Warwick/GOTO  <D.T.H.Steeghs@warwick.ac.uk>

D.Steeghs, J.Lyman (U. Warwick), G.Ramsay (Armagh O.), M.Dyer
(U. Sheffield), K.Ulaczyk, A.Levan, R.Cutter (U. Warwick)
K. Ackley, D.Galloway, E.Rol (Monash U.), V.Dhillon (U. Sheffield),
P.O'Brien, R.Starling (U. Leicester), S.Poshyachinda (NARIT),
D.Pollacco (U. Warwick), E.Thrane (Monash U.)

report on behalf of the GOTO collaboration:

In response to the short-duration GRB 180728B (GCN 23056, 23057, 23060),
the Gravitational-wave Optical Transient Observer (GOTO) observed the
IPN triangulation region as reported in Svinkin et al. (GCN 23056).

Observations were spread over four telescope array pointings,
beginning 2018-07-29T21:24 UT (24.25 hours after the burst) and employ
sets of 3x120s exposures in our wide L filter(400-700nm). These fields
were repeated on 2018-07-30 to permit difference imaging analysis.
Conditions were affected by dust, typically achieved a 5 sigma limiting
magnitude of V=19.8-20.1 on 2018-07-29 and V=20.4-20.6 on 2018-07-30.

We made use of the GLADE galaxy catalog to pay particular attention to
possible source candidates near galaxies within 200 Mpc. We find no
significant sources that could be credibly associated with the GRB.

Furthermore, we see no evidence for a source at the position reported
in Lipunov et al. (GCN 23065), noting that our observations started
4.7 hours later than the MASTER observations and thus the source
may have faded below our detection limit by then.


GOTO is operated at the La Palma observing facilities of the University
of Warwick on behalf of a consortium including the University of
Warwick, Monash University, Armagh Observatory, the University of
Leicester, the University of Sheffield, the National Astronomical
Research Institute of Thailand (NARIT) and the Instituto de Astrofisica
de Canarias (IAC)

https://goto-observatory.org/


GRB_name: GRB180727A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23072
SUBJECT: GRB 180727A: Swift/BAT spectral lag result
DATE:    18/08/03 04:01:20 GMT
FROM:    Takanori Sakamoto at AGU  <tsakamoto@phys.aoyama.ac.jp>

J. P. Norris (BSU), Y. Kawakubo (AGU),
T. Sakamoto (AGU), S. D. Barthelmy (GSFC),
S. B. Cenko (GSFC), A. Y. Lien (GSFC/UMBC)

We report the spectral lag analysis for GRB 180727A
(Beardmore et al., GCN Circ. 23043; Lien et al., GCN Circ. 23047)
based on the BAT data.  The lag analysis finds a lag of 80 +- 27 ms
for the 50-100 keV to 15-25 keV band.  Despite the short T90 duration
(1.1 +- 0.2 s), the lag value is consistent with that of long GRBs.


GRB_name: GRB180720B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23073
SUBJECT: GMRT radio detection of GRB 180720B
DATE:    18/08/03 09:23:31 GMT
FROM:    Poonam Chandra at TIFR  <poonam@ncra.tifr.res.in>

Poonam Chandra (NCRA-TIFR), A. J. Nayana (NCRA-TIFR), Dipankar Bhattacharya (IUCAA), S. Bradley Cenko (NASA) and Alessandra Corsi (Texas-Tech) report:

We observed GRB 180720B (Siegel et al. GCN 22973) with the Giant Metrewave Radio Telescope at the 1.4 GHz band on 2018 Jul 29.99 UT. We detect a radio afterglow with the flux density of ~370+/-59 uJy at the optical position (Martone et al. GCN 22976). 

We thank the staff of the GMRT that made these observations possible. GMRT is run by the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research. More observations are planned.


GRB_name: GRB180805A
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23074
SUBJECT: GRB 180805A: Swift detection of a burst
DATE:    18/08/05 09:23:39 GMT
FROM:    Scott Barthelmy at NASA/GSFC  <scott@milkyway.gsfc.nasa.gov>

P. D'Avanzo (INAF-OAB), S. D. Barthelmy (GSFC),
S. W. K Emery (UCL-MSSL), N. P. M. Kuin (UCL-MSSL),
A. Y. Lien (GSFC/UMBC), A. Melandri (INAF-OAB),
M. J. Moss (George Washington University) and B. Sbarufatti (PSU)
report on behalf of the Neil Gehrels Swift Observatory Team:

At 09:04:49 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180805A (trigger=851829).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 167.530, -45.331 which is 
   RA(J2000) = 11h 10m 07s
   Dec(J2000) = -45d 19' 50"
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 1.5 sec.  The peak count rate
was ~1500 counts/sec (15-350 keV), at ~0 sec after the trigger. 

The XRT began observing the field at 09:06:15.1 UT, 86.1 seconds after
the BAT trigger. Using promptly downlinked data we find an uncatalogued
X-ray source with an enhanced position: RA, Dec 167.5646, -45.3307
which is equivalent to:
   RA(J2000)  = 11h 10m 15.50s
   Dec(J2000) = -45d 19' 50.5"
with an uncertainty of 3.8 arcseconds (radius, 90% containment). This
location is 87 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 http://www.swift.ac.uk/sper.  We
cannot determine whether the source is fading at the present time. 

A power-law fit to a spectrum formed from promptly downlinked event
data gives a column density consistent with the Galactic value of 1.68
x 10^21 cm^-2 (Willingale et al. 2013). 

UVOT took a finding chart exposure of 150 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 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 0.19. 

Burst Advocate for this burst is P. D'Avanzo (paolo.davanzo AT brera.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/too.html.)


GRB_name: GRB180805A
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23075
SUBJECT: GRB 180805A: Enhanced Swift-XRT position
DATE:    18/08/05 12:09:32 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 1075 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 180805A, 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 = 167.56626, -45.33222 which is equivalent
to:

RA (J2000): 11h 10m 15.90s
Dec (J2000): -45d 19' 56.0"

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: GRB180805B
Detection_method: Swift Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23076
SUBJECT: GRB 180805B: Swift detection of a burst
DATE:    18/08/05 13:18:15 GMT
FROM:    Boris Sbarufatti at PSU  <bxs60@psu.edu>

P. D'Avanzo (INAF-OAB), V. D'Elia (ASDC), N. P. M. Kuin (UCL-MSSL),
A. Y. Lien (GSFC/UMBC), F. E. Marshall (NASA/GSFC),
A. Melandri (INAF-OAB) and B. Sbarufatti (PSU) report on behalf of the
Neil Gehrels Swift Observatory Team:

At 13:02:36 UT, the Swift Burst Alert Telescope (BAT) triggered and
located GRB 180805B (trigger=851855).  Swift slewed immediately to the burst. 
The BAT on-board calculated location is 
RA, Dec 25.813, -17.503 which is 
   RA(J2000) = 01h 43m 15s
   Dec(J2000) = -17d 30' 11"
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 1.5 sec.  The peak count rate
was ~4000 counts/sec (15-350 keV), at ~0.1 sec after the trigger. 

The XRT began observing the field at 13:03:53.2 UT, 76.8 seconds after
the BAT trigger. Using promptly downlinked data we find a bright,
fading, uncatalogued X-ray source with an enhanced position: RA, Dec
25.7814, -17.4926 which is equivalent to:
   RA(J2000)  = 01h 43m 07.55s
   Dec(J2000) = -17d 29' 33.2"
with an uncertainty of 2.1 arcseconds (radius, 90% containment). This
location is 114 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
http://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 (1.63 x
10^20 cm^-2, Willingale et al. 2013), with an excess column of 3.1
(+2.89/-2.44) x 10^21 cm^-2 (90% confidence). 

The initial flux in the 2.5 s image was 1.14e-09 erg cm^-2 s^-1 (0.2-10
keV). 

UVOT took a finding chart exposure of 150 seconds with the White filter
starting 84 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
0.02. 

Burst Advocate for this burst is P. D'Avanzo (paolo.davanzo AT brera.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/too.html.)


GRB_name: GRB180805B
Detection_method: Swift-XRT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23077
SUBJECT: GRB 180805B: Enhanced Swift-XRT position
DATE:    18/08/05 16:08:45 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 1323 s of XRT Photon Counting mode data and 1 UVOT
images for GRB 180805B, 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 = 25.78171, -17.49345 which is equivalent
to:

RA (J2000): 01h 43m 7.61s
Dec (J2000): -17d 29' 36.4"

with an uncertainty of 1.8 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: GRB180805B
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23078
SUBJECT: GRB 180805B: Fermi GBM detection
DATE:    18/08/05 22:07:27 GMT
FROM:    Rachel Hamburg at UAH  <rkh0007@uah.edu>

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

"At 13:02:36.52 UT on 05 August 2018, the Fermi Gamma-Ray Burst Monitor
triggered and located GRB 180805B (trigger 555166961 / 180805543)
which was also detected by the Swift BAT and XRT instruments
(D'Avanzo et al. 2018, GCN 23076). The GBM on-ground location is consistent
with the Swift position.

The angle from the Fermi LAT boresight at the GBM trigger time is 64
degrees.

The GBM light curve shows a single peak
with a duration (T90) of about 1 s (50-300 keV).
The time-averaged spectrum from T0-0.13 s to T0+0.58 s is
best fit by a power law function with an exponential
high-energy cutoff.  The power law index is -0.5 +/- 0.2 and
the cutoff energy, parameterized as Epeak, is 346 +/- 75 keV.

The event fluence (10-1000 keV) in this time interval is
(5.9 +/- 0.7)E-07 erg/cm^2. The 64-ms peak photon flux measured
starting from T0+0.06 s in the 10-1000 keV band
is 8.3 +/- 1.1 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB180805B
Detection_method: Swift-UVOT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23080
SUBJECT: GRB 180805B: Swift/UVOT Upper Limits
DATE:    18/08/05 22:12:32 GMT
FROM:    Paul Kuin at MSSL  <npkuin@gmail.com>

N. P. M. Kuin (UCL-MSSL) and P. D'Avanzo (INAF-OAB)
report on behalf of the Swift/UVOT team:

The Swift/UVOT began settled observations of the field of
GRB 180805B  85 s after the BAT trigger (D'Avanzo et al.,
GCN Circ. 23076).  No optical afterglow consistent with the
XRT position (Evans et al. GCN Circ. 23077) 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            85          235          147         >20.8
u_FC               297          546          246         >20.2
white               85         1544          392         >21.3
v                  626         1421           78         >18.6
b                  552         1519           97         >20.0
u                  297          546          246         >20.2
w1                 675         1470           97         >18.8
m2                1078         1097           19         >17.8
w2                 774         1569           78         >19.0

The magnitudes in the table are not corrected for the
Galactic extinction due to the reddening of E(B-V) = 0.02 in
the direction of the burst (Schlegel et al. 1998).


GRB_name: GRB180805A
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23081
SUBJECT: GRB 180805A: Swift-BAT refined analysis
DATE:    18/08/06 01:48:56 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

D. M. Palmer (LANL), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), P. D'Avanzo (INAF-OAB),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), J. P. Norris (BSU),
T. Sakamoto (AGU), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (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 180805A (trigger #851829)
(D'Avanzo et al., GCN Circ. 23074).  The BAT ground-calculated position is
RA, Dec = 167.575, -45.327 deg which is
  RA(J2000)  =  11h 10m 18.1s
  Dec(J2000) = -45d 19' 35.8"
with an uncertainty of 2.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 64%.

The mask-weighted light curve shows a single-pulse structure that starts
at peaks at ~T0, and ends at ~T+1.9 s. T90 (15-350 keV) is 1.68 +- 0.41 sec
(estimated error including systematics).

The time-averaged spectrum from T+0.04 to T+1.90 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.58 +- 0.32.  The fluence in the 15-150 keV band is 1.1 +- 0.3 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T+0.13 sec in the 15-150 keV band
is 1.1 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

Both the temporal and spectral properties of this burst lie in the
intermediate region between short and long GRBs. The lag analysis
is unavailable due to the weakness of this burst. No extended emission
is found.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/851829/BA/


GRB_name: GRB180805B
Detection_method: Swift-BAT Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23082
SUBJECT: GRB 180805B: Swift-BAT refined analysis (short GRB with extended emission)
DATE:    18/08/06 02:00:36 GMT
FROM:    Amy Lien at GSFC  <amy.y.lien@nasa.gov>

T. Sakamoto (AGU), S. D. Barthelmy (GSFC),
J. R. Cummings (CPI), P. D'Avanzo (INAF-OAB),
H. A. Krimm (NSF/USRA), A. Y. Lien (GSFC/UMBC),
C. B. Markwardt (GSFC), J. P. Norris (BSU),
D. M. Palmer (LANL), M. Stamatikos (OSU),
T. N. Ukwatta (LANL) (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 180805B (trigger #851855)
(D'Avanzo et al., GCN Circ. 23076).  The BAT ground-calculated position is
RA, Dec = 25.877, -17.475 deg which is
  RA(J2000)  =  01h 43m 30.6s
  Dec(J2000) = -17d 28' 29.3"
with an uncertainty of 3.1 arcmin, (radius, sys+stat, 90% containment).
The partial coding was 67%.

The mask-weighted light curve show a short pulse that starts from ~T-0.1 s,
peaks at ~T+0.1 s, and ends at ~T+0.7 s. The short pulse is followed by
some weak emission that lasts until ~ T+130 s. T90 (15-350 keV) is
122.5 +- 18.3 sec (estimated error including systematics).

The time-averaged spectrum from T-0.10 to T+127.46 sec is best fit by a simple
power-law model.  The power law index of the time-averaged spectrum is
1.13 +- 0.29.  The fluence in the 15-150 keV band is 9.6 +- 1.7 x 10^-7 erg/cm2.
The 1-sec peak photon flux measured from T-0.11 sec in the 15-150 keV band
is 1.7 +- 0.2 ph/cm2/sec.  All the quoted errors are at the 90% confidence
level.

The structure of the burst shows similarity to those of short GRBs with
extended emission. We thus perform further analysis on the short spike and the
tail emission.

The spectrum of the short pulse from T-0.001 to T+0.712 sec can be fitted by
a simple power-law model with power-law index of 0.66 +- 0.20 and
fluence (15-150 keV) of 1.7 +- 0.2 x 10^-7 erg/cm2. The spectrum of the
extended emission from T+0.712 to T+126.532 sec is best fit by a simple power-law
model, with power-law index of 1.16 +- 0.39 and fluence (15-150 keV) of
6.8 +- 1.6 x 10^-7 erg/cm2. These values are consistent with those of short GRBs
with extended emission (Lien & Sakamoto et al. 2016).

The lag analysis does not produce a well-constrained value due to the weakness
of the short pulse.

The results of the batgrbproduct analysis are available at
http://gcn.gsfc.nasa.gov/notices_s/851855/BA/


GRB_name: GRB180805B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23083
SUBJECT: GRB 180805B: Swift-XRT refined Analysis
DATE:    18/08/06 02:03:06 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

S. J. LaPorte (PSU), J.A. Kennea (PSU), K.L. Page (U. Leicester), A.P.
Beardmore (U. Leicester), P.A. Evans (U. Leicester), A. Melandri
(INAF-OAB), V. D'Elia (ASDC), B. Sbarufatti (INAF-OAB/PSU) and P.
D'Avanzo report on behalf of the Swift-XRT team:

We have analysed 6.6 ks of XRT data for GRB 180805B (D'Avanzo et al.
GCN Circ. 23076), from 82 s to 36.7 ks after the  BAT trigger. The data
comprise 197 s in Windowed Timing (WT) mode with the remainder in
Photon Counting (PC) mode. The enhanced XRT position for this burst was
given by Evans et al. (GCN Circ. 23077).

The light curve can be modelled with a series of power-law decays. The
light curve initially rises, with an index alpha=-1.5 (+0.0, -0.5). At
T+102 s it breaks to an alpha of 1.61 (+0.15, -0.65). The light curve
breaks again at T+241 s to a decay with alpha=3.1 (+/-0.4),  before a
final break at T+891 s s after which the decay index is 0.88 (+0.21,
-0.18).

A spectrum formed from the WT mode data can be fitted with an absorbed
power-law with a photon spectral index of 0.93 (+0.09, -0.06). The
best-fitting absorption column is  2.3 (+4.7, -0.7) x 10^20 cm^-2,
consistent with the Galactic value of 1.6 x 10^20 cm^-2 (Willingale et
al. 2013). The PC mode spectrum has a photon index of 1.90 (+0.25,
-0.23) and a best-fitting absorption column of 7.3 (+6.6, -5.4) x 10^20
cm^-2. The counts to observed (unabsorbed) 0.3-10 keV flux conversion
factor deduced from this spectrum  is 3.5 x 10^-11 (4.0 x 10^-11) erg
cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      7.3 (+6.6, -5.4) x 10^20 cm^-2
Galactic foreground: 1.6 x 10^20 cm^-2
Excess significance: 1.7 sigma
Photon index:      1.90 (+0.25, -0.23)

If the light curve continues to decay with a power-law decay index of
0.88, the count rate at T+24 hours will be 2.0 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 6.8 x
10^-14 (7.8 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/00851855.

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


GRB_name: GRB180805A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23084
SUBJECT: GRB 180805A: Swift-XRT refined Analysis
DATE:    18/08/06 09:25:04 GMT
FROM:    Phil Evans at U of Leicester  <pae9@leicester.ac.uk>

J.A. Kennea (PSU), A.P. Beardmore (U. Leicester), P.A. Evans (U.
Leicester), S.L. Gibson (U. Leicester), V. D'Elia (ASDC), A. D'Ai
(INAF-IASFPA), B. Sbarufatti (INAF-OAB/PSU), D.N. Burrows (PSU) and P.
D'Avanzo report on behalf of the Swift-XRT team:

We have analysed 4.4 ks of XRT data for GRB 180805A (D'Avanzo et al.
GCN Circ. 23074), from 93 s to 12.5 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. 23075).

The light curve can be modelled with a power-law decay with a decay
index of alpha=0.32 (+/-0.14).

A spectrum formed from the PC mode data can be fitted with an absorbed
power-law with a photon spectral index of 1.50 (+0.54, -0.25). The
best-fitting absorption column is  consistent with the Galactic value
of 1.7 x 10^21 cm^-2 (Willingale et al. 2013). The counts to observed
(unabsorbed) 0.3-10 keV flux conversion factor deduced from this
spectrum  is 4.5 x 10^-11 (5.0 x 10^-11) erg cm^-2 count^-1. 

A summary of the PC-mode spectrum is thus:
Total column:      1.7 (+/-2.2) x 10^21 cm^-2
Galactic foreground: 1.7 x 10^21 cm^-2
Excess significance: <1.6 sigma
Photon index:      1.50 (+0.54, -0.25)

If the light curve continues to decay with a power-law decay index of
0.32, the count rate at T+24 hours will be 5.9 x 10^-3 count s^-1,
corresponding to an observed (unabsorbed) 0.3-10 keV flux of 2.7 x
10^-13 (3.0 x 10^-13) erg cm^-2 s^-1.

The results of the XRT-team automatic analysis are available at
http://www.swift.ac.uk/xrt_products/00851829.

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


GRB_name: GRB180805B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23085
SUBJECT: GRB 180805B: MASTER optical late inspection short GRB with extended emission
DATE:    18/08/06 10:52:37 GMT
FROM:    Vladimir Lipunov at Moscow State U/Krylov Obs  <lipunov@xray.sai.msu.ru>

V. Lipunov, N.Tiurina, E. Gorbovskoy,
V.Kornilov, A.Kuznetsov, V.Chazov, I.  Gorbunov,
D.Zimnukhov, D.Kuvshinov, P.Balanutsa, V.Vladimirov, D. Vlasenko
Lomonosov Moscow State University,SAI

D. Buckley,
South African Astronomical Observatory (SAAO)

R. Rebolo, M. Serra, N. Lodieu, G. Israelian, L. Suarez-Andres
The Instituto de Astrofisica de Canarias (IAC)

A. Tlatov, V.Senik, D. Dormidontov
Kislovodsk Solar Station of the Pulkovo Observatory

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

H.Levato,
Instituto de Ciencias Astronomicas, de la Tierra y del Espacio (ICATE)

O. Gres, N.M.Budnev , Yu.Ishmuhametova
Irkutsk State University (ISU)

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


MASTER-SAAO  robotic telescope (MASTER-Net: http://observ.pereplet.ru) 
located in SAAO was starting survey on the Swift short GRB with extended 
emission  GRB180805B (D'Avanzo et 
al., GCN #23076; Hamburg et al., GCN #23078;Sakamoto et al., GCN #23082) 
error-box 
(Evans et al., GCN #23077; )  37838 sec after notice time and 38322 
sec after trigger time at 2018-08-05 23:46:00 UT. The 5-sigma upper limit 
on our first (180s exposure)  set is about 20.5 mag

There is no OT detected.

The message may be cited.


GRB_name: GRB180805B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23086
SUBJECT: GRB 180805B: VLT optical and near-infrared observations
DATE:    18/08/06 13:01:16 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

D. B. Malesani (DAWN/NBI and DARK/NBI), G. Pugliese (API/Univ. 
Amsterdam), P. D'Avanzo (INAF/Brera), N. R. Tanvir (Univ. Leicester), K. 
Wiersema (Univ. Warwick), report on behalf of the Stargate consortium:

We observed the field of GRB 180805B, classified as short with extended 
emission (D'Avanzo et al., GCN 23076; Sakamoto et al., GCN 23082), using 
the ESO Telescopes located in Cerro Paranal. Optical and near-infrared 
observations were obtained using the FORS2 and HAWK-I instruments, 
respectively. No counterpart is detected inside the UVOT-enhanced XRT 
error circle (Evans et al., GCN 23077) in either images, with the 
3-sigma upper limits summarized in the table below.

Filter  Mid time (UT)  Time since GRB (hr)  Limiting mag (Vega)
---------------------------------------------------------------
J       Aug 6.245      16.84                23.5
R       Aug 6.363      19.67                25.5

Calibration was carried out against a single 2MASS star for the J band, 
and using archival FORS2 zeropoints for the R band.

We note the presence of four extended objects within a few arcsec of the 
center of the XRT error circle, including a source 3.5" North of the GRB 
(R ~ 22.5) also visible in the Pan-STARRS r and i images. Their 
association with the GRB cannot be assessed at the present time.

We acknowledge excellent support from the ESO observing staff in 
Paranal, especially Stephane Brillant, Joe Anderson, and Bian Fuyan. DBM 
also acknowledges useful discussion with Amy Lien (GSFC/UMBC) about the 
classification of this GRB.


GRB_name: GRB180805B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23087
SUBJECT: GRB 180805B: GOTO optical limits
DATE:    18/08/06 14:26:16 GMT
FROM:    Danny Steeghs at U.of Warwick/GOTO  <D.T.H.Steeghs@warwick.ac.uk>

G.Ramsay (Armagh O.), K.Ulaczyk, D.Steeghs, J.Lyman (U. Warwick),
M.Dyer (U. Sheffield),  B.Gompertz, A.Levan, R.Cutter (U. Warwick)
K. Ackley, D.Galloway, E.Rol (Monash U.), V.Dhillon (U. Sheffield),
P.O'Brien, R.Starling (U. Leicester), S.Poshyachinda (NARIT),
D.Pollacco (U. Warwick), E.Thrane (Monash U.), E.Palle (IAC)

report on behalf of the GOTO collaboration:

In response to GRB 180805B (D'Avanzo et al. GCN 23076), the
Gravitational-wave Optical Transient Observer (GOTO) observed the
field near the Swift BAT/XRT detection.

Observations started at 2018-08-06T04:37:59 UT (15.5 hours after the
burst) consisting of a set of 6x120s exposures in our wide L filter
(400-700nm). We do not detect any optical source within the error
circle of the enhanced XRT location (Evans et al. GCN 23077) with a
5-sigma limit of V=20.4, using APASS calibrators on the stacked image.

We note that our observations were obtained between those of Lupinov
et al. GCN 23085 and Malesani et al. GCN 23086.

GOTO is operated at the La Palma observing facilities of the University
of Warwick on behalf of a consortium including the University of
Warwick, Monash University, Armagh Observatory, the University of
Leicester, the University of Sheffield, the National Astronomical
Research Institute of Thailand (NARIT) and the Instituto de Astrofisica
de Canarias (IAC)

https://goto-observatory.org/


GRB_name: GRB180805B
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23088
SUBJECT: GRB 180805B: 1.5m OSN I-band observation
DATE:    18/08/06 15:06:38 GMT
FROM:    Youdong HU at IAA-CSIC, UGR  <youdong@iaa.es>

Y.-D. Hu, F.J. Aceituno, J. C. Tello and A.J. Castro-Tirado (IAA-CSIC 
Granada), on behalf of a larger collaboration, report:

Following the detection of GRB 180805B (short burst with extended 
emission) by Swift (D'Avanzo et al. GCNC 23076, Sakamoto et al. GCNC 
23082), optical images in the I-band were obtained at the 1.5m OSN 
telescope in Granada (Spain) starting at 03:08 (Aug 6), i.e. ~14 h 
postburst. No optical afterglow is detected in the co-added image (7 x 
300s, mid time at 03:26 UT, 14.4 h after the trigger) within the 
enhanced Swift/XRT error box (Evans et al. GCNC 23077) down to I=21.0, 
which is in agreement with the non-detections reported by Lipunov et al. 
(GCNC 23085), Malesani et al. (GCNC 23086) and Ramsay et al.(GCNC 
23087).


GRB_name: GRB180805B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23089
SUBJECT: GRB 180805B: COATLI Optical Observations 
DATE:    18/08/06 17:18:16 GMT
FROM:    Alan M. Watson at Instituto de Astronomia UNAM  <alan@astro.unam.mx>

Alan M. Watson (UNAM), Nat Butler (ASU), Rosa L. Becerra (UNAM), William
H. Lee (UNAM), Carlos RomÃ¡n-ZÃºÃ±iga (UNAM), Alexander Kutyrev (GSFC), and
Eleonora Troja (GSFC) report:

We observed the field of the short GRB 180805B (D'Avanzo et al., GCN
Circ. 23076) with the COATLI 50-cm telescope and interim imager at the
Observatorio AstronÃ³mico Nacional on the Sierra de San Pedro MÃ¡rtir
(http://coatli.astroscu.unam.mx) from 2018-08-06 08:01 to 11:48 UTC
(18.98 to 22.77 hours after the trigger), obtaining a total of 2.98
hours of exposure in the w filter.

We do not detect any optical sources within the enhanced XRT error
region (Evans et al., GCN Circ. 23077) to a 5-sigma limiting magnitude
of

w > 22.5

This magnitude is calibrated against the USNO-B1 catalog (adjusted to an
approximate AB system) and is not corrected for Galactic extinction in
the direction of the GRB.

We thank the COATLI technical team (Fernando Ãngeles, Oscar Chapa,
Salvador Cuevas, Alejandro Farah, Jorge Fuentes, RosalÃ­a Langarica,
Fernando QuirÃ³s, and Carlos Tejada) and the staff of the Observatorio
AstronÃ³mico Nacional.


GRB_name: GRB180805B
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23090
SUBJECT: GRB 180805B: ESO/NTT optical observations
DATE:    18/08/06 20:36:48 GMT
FROM:    Klaas Wiersema at U of Warwick  <K.Wiersema@warwick.ac.uk>

A. Higgins (Univ. Leicester), K. Wiersema (Univ. Warwick)  and D. B. Malesani (DAWN/NBI and DARK/NBI) report:

We observed the field of GRB 180805B, classified as short with extended emission (D'Avanzo et al., GCN 23076; Sakamoto et al., GCN 23082), using the ESO New Technology Telescope (NTT) equipped with the EFOSC2 camera. Our observations consist of 9 images in i band, for a total of 1800 s exposure, with mid time 2018 August 6.28 UT (17.76 hr after the GRB trigger), and were
obtained as part of the SPLOT programme (Higgins et al. 2018, subm.).

No counterpart is detected inside the UVOT-enhanced XRT error circle (Evans et al., GCN 23077) in our coadded image, down to a 3-sigma upper limit i > 25 (AB), adopting i = 20.56 for the Pan-STARRS star at RA = 01:43:07.462, Dec = -17:28:30.90.

We thank D. Castex for support with these observations.


GRB_name: GRB180806A
Detection_method: Swift Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23093
SUBJECT: GRB 180806A: Swift ToO observations
DATE:    18/08/07 14:37:16 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/GBM GRB 180806A. 
Automated analysis of the XRT data will be presented online at
http://www.swift.ac.uk/ToO_GRBs/00020812

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/GBM 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: GRB180806A
Detection_method: Fermi GBM Det
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23095
SUBJECT: GRB 180806A: Fermi GBM detection
DATE:    18/08/07 17:35:57 GMT
FROM:    Christian Malacaria at U of Alabama/MSFC  <christian.malacaria@nasa.gov>

C. Malacaria (NASA-MSFC/USRA), R. Hamburg (UAH), and C. Meegan (UAH)
report on behalf of the Fermi GBM Team:

"At 22:38:59.66 UT on 06 August 2018, the Fermi Gamma-Ray Burst
Monitor triggered and located GRB 180806A
(trigger 555287944 / 180806944).

The event was also possibly detected by MASTER OT
(Lipunov et al. 2018, GCN 23091) and COATLI (Watson et al. 2018,
GCN 23092, GCN 23094) and triggered a Swift/XRT ToO
(Evans et al. 2018, GCN 23093).
The GBM on-ground location and the MASTER position are consistent.

The angle from the Fermi LAT boresight at the
GBM trigger time is 66 degrees.

The GBM light curve consists of a single peak
with a duration (T90) of about 15.6 +/- 0.8 s (50-300 keV).
The time-averaged spectrum from T0-1.5 s to T0+16.9 s is
best fit by a Band function with Epeak = 482.40 +/- 31.2,
alpha index = -0.95 +/- 0.02 and beta index = -2.37 +/- 0.19.

The event fluence (10-1000 keV) in this time interval is
(2.197 +/- 0.039)E-05 erg/cm^2. The 1-sec peak photon flux
Measured starting from T0+4.9 s in the 10-1000 keV band
is 14.3 +/- 0.3 ph/s/cm^2.

The spectral analysis results presented above are preliminary;
final results will be published in the GBM GRB Catalog."


GRB_name: GRB180806A
Detection_method: Swift-XRT Other
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23097
SUBJECT: GRB 180806A: Swift-XRT afterglow detection
DATE:    18/08/07 22:15:00 GMT
FROM:    Antonino D'Ai at IASF-PA  <antonino.dai@ifc.inaf.it>

S.L. Gibson (U. Leicester), Z. Liu (NAOC / U. Leicester), V. D'Elia
(ASDC), A. D'Ai (INAF-IASFPA), A. Melandri (INAF-OAB), B. Sbarufatti
(INAF-OAB/PSU), D.N. Burrows (PSU), A. Tohuvavohu (PSU) and P.A. Evans
(U. Leicester) report on behalf of the Swift-XRT team:

Swift-XRT has performed follow-up observations of the
Fermi/GBM-detected burst GRB 180806A (Malacaria et al. GCN Circ.
23095), collecting 1.8 ks of Photon Counting (PC) mode data between
T0+57.6 ks and T0+76.2 ks. 

Two uncatalogued X-ray sources are detected, of which one ("Source 1")
is fading with 3-sigma significance, and is therefore likely the GRB
afterglow.  The position of this source is RA, Dec=11.5536, +24.3370
which is equivalent to:

RA (J2000): 00:46:12.86
Dec(J2000): +24:20:13.2

with an uncertainty of 5.0 arcsec (radius, 90% confidence). 
This position is 1.3 arcsec from the Fermi/GBM position and 2.7 arcsec
from the OT position reported by Lipunov (GCN 23091) and Watson (GCN
23092).

The source is fading with alpha >2.2.

The results of the XRT-team automatic analysis of the likely afterglow
are at http://www.swift.ac.uk/ToO_GRBs/00020812/Source1.php.
The results of the full analysis of the XRT observations are available
at http://www.swift.ac.uk/ToO_GRBs/00020812.

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


GRB_name: GRB180806A
Detection_method: Optical
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23098
SUBJECT: GRB 180806A: NOT optical observations
DATE:    18/08/08 02:13:55 GMT
FROM:    Daniele Malesani at Dark Cosmology Centre, Niels Bohr Inst  <malesani@dark-cosmology.dk>

Daniele BjÃ¸rn Malesani (DAWN/NBI and DARK/NBI) and Ana Sagues (NOT) report:

We observed the candidate optical counterpart (Lipunov et al., GCN 
23091; Watson et al., GCN 23092) of the Fermi GRB 180806A (Malacaria et 
al., GCN 23095) using the Nordic Optical Telescope (NOT) equipped with 
the AlFOSC camera.

In a single 300 s exposure centered on 2018 Aug 8.07 UT (27.09 hr after 
the GRB), we detect the candidate afterglow with a magnitude r = 22.31 
+- 0.10 AB, calibrated against nearby stars from the Pan-STARRS catalog.

The continued fading compared to previous reports (Lipunov et al., GCN 
23091; Butler et al., GCN 23094; Watson et al., GCN 23096), as well as 
the spatial coincidence with an X-ray source (Gibson et al., GCN 23097) 
confirm the interpretation of this source as the optical afterglow of 
GRB 180806A.


GRB_name: GRB180723A
Detection_method: AstroSat CZTI
Circular_text:
TITLE:   GCN CIRCULAR
NUMBER:  23099
SUBJECT: GRB 180723A: AstroSat CZTI detection
DATE:    18/08/08 07:57:10 GMT
FROM:    Vidushi Sharma at IUCAA  <vidushi@iucaa.in>

V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (TIFR) and S. Vadawale (PRL) report on behalf of the Astrosat CZTI collaboration:

Analysis of Astrosat CZTI data showed the detection of a bright GRB 180723A, which was also detected by CALET (Ishizaki W. et al., GCN 23029) and Fermi-GBM (Poolakkil S. et al., GCN 23035).

The source was clearly detected in the 40-200 keV energy range. The light curve shows multiple peaks of emission with strongest peak at 18:09:49.50 UT. The measured peak count rate is 1123.5 cts/s above the background in combined data of four quadrants, with a total of 6717 cts. The local mean background count rate was 543.5 cts/s. Using cumulative rates, we measure a T90 of 25.3 s. In preliminary analysis, we find that 459 compton events are associated with this event.

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.


