{
  "bibcode": "2023GCN.33415....1N",
  "body": "P K. Navaneeth (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 the extremely bright long \nGRB 230307A which was also detected by Fermi-GBM (Fermi GBM team, GCN \n33405), GECAM (Xiong et al., GCN 33406), Solar Orbiter STIX (Xiao et \nal., GCN 33410), AGILE/MCAL (Casentini et al., GCN 33412) and IPN \n(Kozyrev et al., GCN 33413).\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 \n2023-03-07 15:44:10.0 UTC. The measured peak count rate associated with \nthe burst is 4041 (+33, -37) counts/s above the background in the \ncombined data of all quadrants, with a total of 90900 (+758, -850) \ncounts. The local mean background count rate was 453 (+1, -1) counts/s. \nUsing cumulative rates, we measure a T90 of 33 (+1, -1) s. In the \npreliminary analysis, we find 5484 Compton events associated with this \nevent.\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 2023-03-07 15:44:15.17 UTC. The \nmeasured peak count rate is 276156 (+268, -300) counts/s above the \nbackground in the combined Veto data of all quadrants, with a total of \n5571313 (+4953, -6044) counts. The local mean background count rate was \n14750 (+7, -6) counts/s. We measure a T90 of 40 (+0.2, -0.2) s from the \ncumulative Veto light curve.\n\nCZTI is built by a TIFR-led consortium of institutes across India, \nincluding VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research \nOrganisation funded, managed, and facilitated the project. CZTI GRB \ndetections are reported regularly on the payload site at:\nhttp://astrosat.iucaa.in/czti/?q=grb",
  "circularId": 33415,
  "createdOn": 1678256272000,
  "email": "gauravwaratkar@iitb.ac.in",
  "subject": "GRB 230307A: AstroSat CZTI detection",
  "submitter": "Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>",
  "eventId": "GRB 230307A"
}