{
  "bibcode": "2022GCN.32969....1G",
  "body": "R. Gopalakrishnan (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. \nBhalerao (IITB), D. Bhattacharya (Ashoka University/IUCAA), A. R. Rao \n(IUCAA/TIFR), and S. Vadawale (PRL) report on behalf of the AstroSat \nCZTI collaboration:\n\nAnalysis of AstroSat CZTI data with the CIFT framework (Sharma et al., \n2021, JApA, 42, 73) showed the detection of a long GRB221121A which was \nalso detected by Fermi GBM (GCN Circ. 32960).\n\nThe source was clearly detected in the 20-200 keV energy range. The \nlight curve peaks at 2022-11-21 06:34:50.5 UTC. The measured peak count \nrate associated with the burst is 173 (+42, -40) counts/s above the \nbackground in the combined data of all quadrants, with a total of 1531 \n(+490, -529) counts. The local mean background count rate was 532 (+3, \n-4) counts/s. Using cumulative rates, we measure a T90 of 22 (+15, -9) \ns.\n\nIt was also clearly detected in the CsI anticoincidence (Veto) detector \nin the 100-500 keV energy range. The light curve peaks at 2022-11-21 \n06:34:53.9 UTC. The measured peak count rate is 283 (+79, -30) counts/s \nabove the background in the combined Veto data of all quadrants, with a \ntotal of 3488 (+696, -662) counts. The local mean background count rate \nwas 1746 (+6, -6) counts/s. We measure a T90 of 22 (+10, -4) s from the \ncumulative Veto light curve.\n\nCZTI GRB detections are reported regularly on the payload site at \nhttp://astrosat.iucaa.in/czti/?q=grb. CZTI is built by a TIFR-led \nconsortium of institutes across India, including VSSC, URSC, IUCAA, SAC, \nand PRL. The Indian Space Research Organisation funded, managed, and \nfacilitated the project.",
  "circularId": 32969,
  "createdOn": 1669114393000,
  "email": "gauravwaratkar@iitb.ac.in",
  "subject": "GRB221121A: AstroSat CZTI detection",
  "submitter": "Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>",
  "eventId": "GRB 221121A"
}