GCN 45164: GRB 260709A: AstroSat CZTI detection

S.Salunke (IUCAA), Harsha K. H. (IUCAA), A. Goyal (IITB), A. Arya (IITB), G. Waratkar (Caltech/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  GRB 260709A which was also detected by Fermi (Fermi GBM team, GCN Circ. 45121), VOM/GRM (SVOM/GRM team, GCN Circ. 45137).

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 2026-07-09 01:07:50.62 UTC. The measured peak count rate associated with the burst is 108 (+32, -14) counts/s above the background in the combined data of three quadrants (out of four), with a total of 1034 (+278, -266) counts. The local mean background count rate was 207 (+2, -3) counts/s. We measure a T90 of 26 (+10, -8) s from the cumulative CZT light curve. We note that the burst is relatively weak, hence theT90 measurement has a larger uncertainty than usual. 

CZTI data products like interactive and downloadable light curves for this GRB can be found at:https://astrosat.iucaa.in/cift/cift_products/ET20260709T010732/ET20260709T010732_details.html

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