//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29732 SUBJECT: GRB 210328A: Fermi GBM Final Real-time Localization DATE: 21/03/28 20:55:25 GMT FROM: Fermi GBM Team at MSFC/Fermi-GBM The Fermi GBM team reports the detection of a likely LONG GRB At 20:45:16 UT on 28 Mar 2021, the Fermi Gamma-ray Burst Monitor (GBM) triggered and located GRB 210328A (trigger 638657121.97022 / 210328865). The on-ground calculated location, using the Fermi GBM trigger data, is RA = 207.9, Dec = -8.6 (J2000 degrees, equivalent to J2000 13h 51m, -8d 35'), with a statistical uncertainty of 2.1 degrees. The angle from the Fermi LAT boresight is 79.0 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210328865/quicklook/glg_skymap_all_bn210328865.png The HEALPix FITS file, including the estimated localization systematic, can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210328865/quicklook/glg_healpix_all_bn210328865.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210328865/quicklook/glg_lc_medres34_bn210328865.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29733 SUBJECT: GRB 210328A: BALROG localization (Fermi Trigger / GRB 210328865) DATE: 21/03/28 21:17:20 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 at 20:45:16 on 28 March 2021 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) = 205.9+/-1.3 deg Decl.(2000.0) = -11.4+/-1.5 deg We estimate an additional systematic error of 1 deg. Further details are available at: https://grb.mpe.mpg.de/grb/GRB210328865/?data_version=h00 The Healpix map can be downloaded from: https://grb.mpe.mpg.de/media/data/GRB210328865/data_files/210328_211506727701_GRB210328865_healpix_trigdat_h00.fits The location parameters are available as JSON at: https://grb.mpe.mpg.de/grb/GRB210328865/json //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29737 SUBJECT: GRB 210328A: GECAM detection DATE: 21/03/30 15:38:19 GMT FROM: Shaolin Xiong at IHEP X. Y. Zhao, S. L. Xiong, X. Y. Song, D. Y. Guo, Y. Huang, S. Xiao, C. Cai, Y. Zhao, J. C. Liu, Q. B. Yi, Y. Q. Zhang, W. C. Xue, C. Zheng, Z. W. Guo,  P. Wang, X. B. Li, W. X. Peng, R. Qiao, C. W. Wang, Z. H. An, C. Chen, G. Chen, W. Chen, M. Gao, K. Gong, D. Y. Guo, J. J. He, B. Li, C. Li, C. Y. Li, J. H. Li, Q. X. Li, X. Q. Li, Y. G. Li, X. H. Liang, J. Y. Liao, J. C. Liu, X. J. Liu, Y. Q. Liu, F. J. Lu, Q. Luo, X. Ma, G. Ou,  D. L. Shi, J. Y. Shi, L. M. Song, G. X. Sun, X. L. Sun, Y. L. Tuo, J. Z. Wang, X. Y. Wen, Y. B. Xu, Y. P. Xu, S. Yang, M. Yao, B. X. Zhang, C. Y. Zhang, D. L. Zhang, Fan Zhang, Fei Zhang, H. M. Zhang, K. Zhang, P. Zhang, S. N. Zhang, Z. Zhang, S. Y. Zhao, S. J. Zheng, X. Zhou (IHEP), report on behalf of GECAM team: During the commissioning phase, GECAM-B triggered by a long burst, GRB 210328A, at 2021-03-28 20:45:17.900 UTC (T0), which was also detected by Fermi/GBM (GCN #29732) According to the GECAM-B light curves in about 20 keV - 500 keV, this burst mainly consists of a broad pulse with duration of about 12 s. Spectral evolution is clearly seen during the burst, and the emissions in low energies last longer than that in high energies. Although the in-flight calibration of energy response and localization has not been finalized yet, GECAM-B localized this burst to the following position (J2000): Ra: 201.9 deg Dec: -2.6 deg Err: 3.4 deg (1-sgima, statistical only) The current systematic error of location is estimated to be several degrees which could be minimized by the ongoing calibration. GECAM location is consistent with the Fermi/GBM and BALROG positions within the error. The GECAM light curve could be found here: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/multiLCvsE_tn210328_204626.pdf The GECAM preliminary location could be found here: http://twiki.ihep.ac.cn/pub/GECAM/GRBList/tn210328_204626_locSatB.pdf Please note that all GECAM results here are preliminary. The final analysis will be published in journal papers or GECAM online catalog. Gravitational wave high-energy Electromagnetic Counterpart All-sky Monitor (GECAM) mission consists of two small satellites (GECAM-A and GECAM-B) in Low Earth Orbit (600 km, 29 deg), launched on Dec 10, 2020 (Beijing Time), which was funded by the Chinese Academy of Sciences (CAS). //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29746 SUBJECT: GRB 210328A: AstroSat CZTI detection DATE: 21/04/03 04:49:11 GMT FROM: Gaurav Waratkar at IIT Bombay P. Sawant (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), S. Gupta (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat CZTI collaboration: Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al, 2020, arxiv:2011.07067) showed detection of a long GRB 210328A, which was also detected by Fermi-GBM (GCN #29732, #29733) and GECAM-B (GCN #29737). The source was clearly detected in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2021-03-28 20:45:21.5 UT. The measured peak count rate associated with the burst is 338 (+48, -45) cts/s above the background in the combined data of four quadrants, with a total of 4242 (+496, -511) cts. The local mean background count rate was 528 (+2, -3) cts/s. Using cumulative rates, we measure a T90 of 39 (+10, -13) 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 2021-03-28 20:45:18.1 UT. The measured peak count rate is 296 (+85, -28) cts/s above the background in the combined Veto data of four quadrants, with a total of 3378 (+447, -604) cts. The local mean background count rate was 1740 (+6, -5) cts/s. We measure a T90 of 18 (+3, -4) 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.