//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29349 SUBJECT: GRB 210123A: Insight-HXMT/HE detection DATE: 21/01/24 05:44:27 GMT FROM: Wangchen Xue at IHEP W. C. Xue, C. Cai, J. C. Liu, Q. Luo, S. Xiao, Q. B. Yi, Y. Q. Zhang, C. Zheng, Y. Huang, C. K. Li, G. Li, X. B. Li, J. Y. Liao, X. Y. Song, 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 2021-01-23T07:19:10.350 (T0), Insight-HXMT/HE detected GRB 210123A (trigger ID: HEB210123304) in a routine search of the data, which also triggered INTEGRAL and IPN. The Insight-HXMT/HE light curve mainly consists of multiple pulses with a duration (T90) of 6.56 s measured from T0-0.52 s. The 1-ms peak rate, measured from T0+1.95 s, is 1825 cnts/sec. The total counts from this burst is 5536 counts. URL_LC: http://twiki.ihep.ac.cn/pub/HXMT/GRBList/HEB210123304_lc.jpg All measurements above are made with the CsI detectors operating in the GRB 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. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29351 SUBJECT: GRB 210123A: Fermi GBM Final Localization DATE: 21/01/25 21:39:52 GMT FROM: Rachel Dunwoody at UCD The Fermi GBM team reports the detection of a likely long GRB. "At 07:19:03.07 UT on 23 January 2021, the Fermi Gamma-Ray Burst Monitor (GBM) triggered and located GRB 210123A (trigger 633079148 / 210123305). This burst was also independently detected by INTEGRAL SPI-ACS and the Insight-HXMT/HE (Xue et al. 2019, GCN 29349) The on-ground calculated location, using the GBM trigger data, is RA = 345.1, DEC = -56.9 (J2000 degrees, equivalent to 23h 00m, -56d 53'), with a statistical uncertainty of 1.1 degrees. The angle from the Fermi LAT boresight is 110 degrees. The skymap can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210123305/quicklook/glg_skymap_all_bn210123305.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/bn210123305/quicklook/glg_healpix_all_bn210123305.fit The GBM light curve can be found here: https://heasarc.gsfc.nasa.gov/FTP/fermi/data/gbm/triggers/2021/bn210123305/quicklook/glg_lc_medres34_bn210123305.gif //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29366 SUBJECT: GRB 210123A: AstroSat CZTI detection DATE: 21/01/29 05:46:19 GMT FROM: Gaurav Waratkar at IIT,Bombay D. Nadella (NITK), G. Waratkar (IITB), A. Vibhute (IUCAA), S. Gupta (IUCAA), P. Sawant (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 210123A, which was also detected by Insight-HXMT/HE (GCN #29349) and Fermi-GBM (GCN #29351). The source was detected in the 20-200 keV energy range. The light curve showed a single peak of emission at 2021-01-23 07:19:08.5 UT. Quadrant A was noisy, and we exclude it from further analysis. The measured peak count rate associated with the burst is 205 (+40, -38) cts/s above the background in the combined data of three quadrants (out of four), with a total of 996 (+259, -237) cts. The local mean background count rate was 394 (+3, -3) cts/s. Using cumulative rates, we measure a T90 of 14 (+5, -4) 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 2021-01-23 07:19:09.1 UT in all four quadrants. The measured peak count rate is 1710 (+95, -102) cts/s above the background in the combined Veto data of four quadrants, with a total of 8982 (+648, -679) cts. The local mean background count rate was 1817 (+5, -7) cts/s. We measure a T90 of 14 (+5, -1) 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.