GRB 200928B
GCN Circular 28521
Subject
GRB 200928B: Fermi GBM Final Real-time Localization
Date
2020-09-28T13:24:54Z (5 years ago)
From
Fermi GBM Team at MSFC/Fermi-GBM <do_not_reply@GIOC.nsstc.nasa.gov>
The Fermi GBM team reports the detection of a likely LONG GRB
At 13:14:39 UT on 28 Sep 2020, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 200928B (trigger 622991684.150156 / 200928552).
The on-ground calculated location, using the Fermi GBM trigger data, is RA = 74.5, Dec = -11.6 (J2000 degrees, equivalent to J2000 04h 58m, -11d 35'), with a statistical uncertainty of 2.8 degrees.
The angle from the Fermi LAT boresight is 83.0 degrees.
The skymap can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200928552/quicklook/glg_skymap_all_bn200928552.png
The HEALPix FITS file, including the estimated localization systematic, can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200928552/quicklook/glg_healpix_all_bn200928552.fit
The GBM light curve can be found here:
https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2020/bn200928552/quicklook/glg_lc_medres34_bn200928552.gif
GCN Circular 28522
Subject
GRB 200928B: BALROG localization (Fermi Trigger 622991684 / GRB 200928552)
Date
2020-09-28T13:41:28Z (5 years ago)
From
Jochen Greiner at MPE,Garching <jcg@mpe.mpg.de>
B. Biltzinger, F. Kunzweiler, F. Berlato, J. Burgess & J. Greiner (all MPE Garching) report:
The public trigdat data of the Fermi Gamma-ray Burst Monitor (GBM) trigger
622991684 at 13:14:39 on 28 Sept. 2020 were automatically fitted for spectrum
and sky location with BALROG (Burgess et al. 2018, MNRAS 476, 1427;
Berlato et al. 2019, ApJ 873, 60).
The best-fit position (1 sigma statistical errors) is:
RA(2000.0) = 80.3+/-2.6 deg
Decl.(2000.0) = -10.0+/-3.0 deg
We estimate an additional systematic error of 2 deg.
Further details are available at:
https://grb.mpe.mpg.de/grb/GRB200928552/
The Healpix map can be downloaded from:
https://grb.mpe.mpg.de/grb/GRB200928552/healpix
The location parameters are available as JSON at:
https://grb.mpe.mpg.de/grb/GRB200928552/json
GCN Circular 28526
Subject
GRB 200928B: AstroSat CZTI detection
Date
2020-09-29T08:30:54Z (5 years ago)
From
Soumya Gupta at IUCAA/ASTROSAT <soumya@iucaa>
S. Gupta, V. Sharma and D. Bhattacharya (IUCAA), V. Bhalerao (IIT-B), A. R. Rao (IUCAA/TIFR) and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration:
Analysis of AstroSat CZTI data showed detection of a long GRB 200928B, which was also detected by Fermi GBM (GCN #28521) and BALROG (Biltzinger B. et al., GCN #28522).
The source was clearly detected in the 40-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2020-09-28 13:14:43.203 UT. The measured peak count rate associated with the burst is 221 +/- 22 cts/s above the background in the combined data of four quadrants, with a total of 1755 +/- 19 cts. The local mean background count rate was 448 +/- 1 cts/s. Using cumulative rates, we measure a T90 of 15.20 +/- 0.02 s.
It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2020-09-28 13:14:44.792 UT. The measured peak count rate is 209 +/- 29 cts/s above the background in the combined Veto data of four quadrants, with a total of 1401 +/- 40 cts. The local mean background count rate was 1561 +/- 2 cts/s. We measure a T90 of 15.81 +/- 0.89 s from the cumulative Veto light curve.
CZTI GRB detections are reported regularly on the payload site at http://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, ISAC, IUCAA, SAC and PRL. The Indian Space Research Organisation funded, managed and facilitated the project.
GCN Circular 28533
Subject
GRB 200928B: Insight-HXMT/HE detection
Date
2020-09-30T01:07:25Z (5 years ago)
From
Shuo Xiao at IHEP <xiaoshuo@ihep.ac.cn>
S. Xiao, Y. Q. Zhang, C. Cai, Y. F. Du, Y. G. Zheng, Q. Luo, Q. B. Yi,
Y. Huang, C. K. Li, G. Li, X. B. Li, J. Y. Liao, S. L. Xiong,
C. Z. Liu, X. F. Li, Z. W. Li, Z. Chang, 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,
M. Wu, Y. P. Xu, S. N. Zhang (IHEP),
report on behalf of the Insight-HXMT team:
At 2020-09-28T13:14:44.750 (T0), Insight-HXMT/HE detected
GRB 200928B (trigger ID: HEB200928551) in a routine search of the data,
which also triggered Fermi-GBM (Fermi GBM team, GCN#28521) and
AstroSat CZTI (Gupta, GCN#28526).
The Insight-HXMT/HE light curve mainly consists of multiple
pulses with a duration (T90) of 14.86 s measured from T0-5.06 s.
The 1-ms peak rate, measured from T0+1.51 s, is 1437 cnts/sec.
The total counts from this burst is 9602 counts.
URL_LC: http://twiki.ihep.ac.cn/pub/HXMT/GRBList/HEB200928551_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 (deposited 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.
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.