//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28521 SUBJECT: GRB 200928B: Fermi GBM Final Real-time Localization DATE: 20/09/28 13:24:54 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM 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 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28522 SUBJECT: GRB 200928B: BALROG localization (Fermi Trigger 622991684 / GRB 200928552) DATE: 20/09/28 13:41:28 GMT FROM: Jochen Greiner at MPE,Garching 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 //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28526 SUBJECT: GRB 200928B: AstroSat CZTI detection DATE: 20/09/29 08:30:54 GMT FROM: Soumya Gupta at IUCAA/ASTROSAT 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 28533 SUBJECT: GRB 200928B: Insight-HXMT/HE detection DATE: 20/09/30 01:07:25 GMT FROM: Shuo Xiao at IHEP 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.