GRB 230313A: AstroSat CZTI detection

Analysis of AstroSat CZTI data with the CIFT framework (Sharma et al., 2021, JApA, 42, 73) showed the detection of a long GRB 230313A which was also detected by Fermi GBM (GCN Circ. 33467). The source was faintly detected in the 20-200 keV energy range. The light curve peaks at 2023-03-13 11:38:43.9 UTC. The measured peak count rate associated with the burst is 211.1 (+167.6 -9.9) counts/s above the background in the combined data of three quadrants (out of four), with a total of 259 (+104 -110) counts. The local mean background count rate was 371.0 (+8.7 -8.6) counts/s. Using cumulative rates, we measure a T90 of 3.68 (+0.61 -2.44) s. It was also faintly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2023-03-13 11:38:43.2 UTC. The measured peak count rate is 270.4 (+59.6 -65.5) counts/s above the background in the combined Veto data of three quadrants (out of four), with a total of 463 (+172 -181) counts. The local mean background count rate was 1116.0 (+5.4 -6.4) counts/s. We measure a T90 of 4.28 (+1.18 -3.20) s from the cumulative Veto light curve. CZTI is built by a TIFR-led consortium of institutes across India, including VSSC, URSC, IUCAA, SAC, and PRL. The Indian Space Research Organisation funded, managed, and facilitated the project. CZTI GRB detections are reported regularly on the payload site at: http://astrosat.iucaa.in/czti/?q=grb