TITLE:   GCN CIRCULAR
NUMBER:  35886
SUBJECT: GRB 240305C: AstroSat CZTI detection of a short burst
DATE:    24/03/06 08:35:52 GMT
FROM:    Gaurav Waratkar at IIT Bombay <gauravwaratkar24@gmail.com>

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 short-duration GRB 240305C which was also detected by Fermi-GBM (Fermi GBM team, GCN Circ. 35881).

The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2024-03-05 22:16:36.87 UTC. The measured peak count rate associated with the burst is 606 (+300, -112) counts/s above the background in the combined data of three quadrants (out of four), with a total of 104 (+31, -29) counts. The local mean background count rate was 258 (+9, -16) counts/s. Using cumulative rates, we measure a T90 of 0.45 (+0.04, -0.12) s.

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