TITLE:   GCN CIRCULAR
NUMBER:  36638
SUBJECT: GRB 240607A: AstroSat CZTI detection of bright long burst
DATE:    24/06/07 14:17:26 GMT
FROM:    Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>

G. Waratkar (IITB),  V. Jethwani (IITB), A. Dasgupta (BITS Hyderabad), J. Joshi (IUCAA), 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 the bright long-duration GRB 240607A which was also detected by Fermi-GBM (GCN Circ. 36634).

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 2024-06-07 11:01:25.500 UTC. The measured peak count rate associated with the burst is 880 (+57, -64) counts/s above the background in the combined data of all quadrants, with a total of 3987 (+214, -257) counts. The local mean background count rate was 447 (+5, -5) counts/s. Using cumulative rates, we measure a T90 of 12.3 (+0.3, -0.4) s.

It was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve showed multiple peaks of emission with the strongest peak at 2024-06-07 11:01:24.9 UTC. The measured peak count rate is 4919 (+128, -137) counts/s above the background in the combined Veto data of all quadrants, with a total of 23001 (+510, -531) counts. The local mean background count rate was 1474 (+5, -5) counts/s. We measure a T90 of 12.6 (+0.2, -0.2) 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