GCN Circular 35518

J. Joshi (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 long-duration GRB 240110A which was also detected by GECAM (Trigger Num. 257), and INTEGRAL-SPIACS (Trigger Num. 10463).

The source was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2024-01-10 14:53:30.07 UTC. The measured peak count rate associated with the burst is 348 (+65, -56) counts/s above the background in the combined data of all quadrants, with a total of 3083 (+366, -468) counts. The local mean background count rate was 1334 (+6, -5) counts/s. We measure a T90 of 16 (+4, -2) s from the cumulative Veto light curve.

The source was also detected in the CZT detectors in the 20-200 keV energy range but we cannot make quantitative inferences due to data quality issues.

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