//////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29340 SUBJECT: GRB 210116: AstroSat LAXPC detection DATE: 21/01/21 07:51:44 GMT FROM: Tilak Katoch at TIFR H. M. Antia, Tilak Katoch, Parag Shah and Dhiraj Dedhia TIFR, Mumbai, India. Analysis of AstroSat LAXPC data showed the detection of a long GRB 210116. The light curve showed a peak profile triggered at T0 = 05h 53m 33s UT on 16 Jan 2021. The light curve showed a peak profile with T90 = 9 sec. The measured peak count rate above the background associated with the burst is 867 +/- 37 cts/s in LAXPC10 and 773 +/- 31 cts/s in LAXPC20 at T0+4 sec. The total counts in the peak are 3219 +/- 85 cts in LAXPC10 and 2683 +/- 68 in LAXPC 20. Both LAXPC instruments (LAXPC10 and LAXPC20) have registered this burst profile in the light curve. For LAXPC20 the nominal energy range is 3-100 keV, but due to lower gain in LAXPC10 the energy range is about 30-400 keV. The background subtracted light curve with 1 sec time-bin is available at the web-site: https://www.tifr.res.in/~astrosat_laxpc/grb210116lc.jpg LAXPC was built by TIFR in collaboration with the Indian Space Research Organisation. The Indian Space Research Organisation funded, managed and facilitated the project. //////////////////////////////////////////////////////////////////////// TITLE: GCN CIRCULAR NUMBER: 29342 SUBJECT: GRB 210116A: AstroSat CZTI detection DATE: 21/01/22 03:24:25 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 bright long GRB 210116A, which was also detected by AstroSat LAXPC (GCN #29340). The source was clearly detected in the 20-200 keV energy range. The light curve showed a single strong peak at 2021-01-16 05:53:37.500 UT, in all four quadrants of CZTI. Quadrant D was noisy, and we exclude it from further analysis. The measured peak count rate associated with the burst is 781 (+54, -60) cts/s above the background in the combined data of three quadrants (out of four), with a total of 3156 (+232, -222) cts. The local mean background count rate was 395 (+3, -3) cts/s. Using cumulative rates, we measure a T90 of 9.5 (+4.1, -1.8) s. It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed a single strong peak of emission in all four quadrants, with the strongest peak consistent with the above timing. The measured peak count rate is 3039 (+131, -62) cts/s above the background in the combined Veto data of four quadrants, with a total of 13614 (+475, -578) cts. The local mean background count rate was 1842 (+6, -6) cts/s. We measure a T90 of 8.8 (+1.7, -1.0) 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.