{
  "bibcode": "2023GCN.33268....1W",
  "body": "G. Waratkar (IITB), P K. Navaneeth (IUCAA), P. Shetty (IITB), A. Ahmad \n(IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka \nUniversity/IUCAA), A. R. Rao (IUCAA/TIFR), and S. Vadawale (PRL) report \non behalf of the AstroSat CZTI collaboration:\n\nAnalysis of AstroSat CZTI data with the CIFT framework (Sharma et al., \n2021, JApA, 42, 73) showed the detection of the bright long GRB 230204B \nwhich was also detected by MAXI-GSC (GCN Circ. 33265), SWIFT/BAT-GUANO \n(GCN Circ. 33267), along with CALET, INTEGRAL and FERMI notices.\n\nThe source was clearly detected in the 20-200 keV energy range. The \nlight curve showed multiple peaks of emission with the strongest peak at \n2023-02-04 21:45:19.5 UTC. The measured peak count rate associated with \nthe burst is 175.4 (+27.7 -26.6) counts/s above the background in the \ncombined data of all four quadrants, with a total of 7611 (+557 -740) \ncounts. The local mean background count rate was 131.2 (+0.7 -0.9) \ncounts/s. Using cumulative rates, we measure a T90 of 216.64 (+5.13 \n-22.56) s. In the preliminary analysis, we find 3240 Compton events \nassociated with this event.\n\nIt was also clearly detected in the CsI anticoincidence (Veto) detector \nin the 100-500 keV energy range. The light curve showed multiple peaks \nof emission with the strongest peak at 2023-02-04 21:45:18.7 UTC. The \nmeasured peak count rate is 1315.9 (+79.7 -88.8) counts/s above the \nbackground in the combined Veto data of all four quadrants, with a total \nof 48625 (+1487 -1923) counts. The local mean background count rate was \n1273.2 (+2.4 -1.8) counts/s. We measure a T90 of 212.32 (+2.94 -7.75) s \nfrom the cumulative 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": 33268,
  "createdOn": 1675575585000,
  "email": "gauravwaratkar@iitb.ac.in",
  "subject": "GRB 230204B: AstroSat CZTI detection",
  "submitter": "Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>",
  "eventId": "GRB 230204B"
}