GCN Circular 34538

P. K. Navaneeth (IUCAA), G. Waratkar (IITB), A. Vibhute (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (Ashoka University/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., 2021, JApA, 42, 73) showed the detection of a GRB 230824B which was also detected by GECAM-B (Trigger Num. 214).

The source was clearly detected in the 20-200 keV energy range. The light curve peaks at 2023-08-24 02:26:50.45 UTC. We see at least two narrow distinct emission episodes. The measured peak count rate associated with the burst is 1044 (+201, -147) counts/s above the background in the combined data of all quadrants, with a total of 704 (+170, -185) counts. The local mean background count rate was 464 (+7, -9) counts/s. Using cumulative rates for the full burst, we measure a T90 of 4.0 (+1.5, -1.4) s. 

The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2023-08-24 02:26:50.21 UTC. The measured peak count rate associated with the burst is 292 (+71, -46) counts/s above the background in the combined data of all quadrants, with a total of 824 (+293, -358) counts. The local mean background count rate was 1529 (+5, -5) counts/s. We measure a T90 of 5.9 (+3.7, - 3.9) 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