TITLE:   GCN CIRCULAR
NUMBER:  45689
SUBJECT: GRB 260917C: AstroSat CZTI detection
DATE:    26/09/22 06:02:22 GMT
FROM:    Anuraag Arya at IIT Bombay <aryaanuraag910@gmail.com>

Harsha K. H. (IUCAA), S. Salunke(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 GRB 260917C which was also detected by Fermi (Fermi GBM team, GCN Circ. 45618).

The source was clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2026-09-17 23:54:04.17 UTC.The measured peak count rate associated with the burst is 101 (+53, -2) counts/s above the background in the combined data of three quadrants (out of four), with a total of 1286 (+366, -401) counts. The local mean background count rate was 533 (+3, -4) counts/s. We measure a T90 of 32 (+5, -8) s from the cumulative Veto light curve.

CZTI data products like interactive and downloadable light curves for this GRB can be found at: https://astrosat.iucaa.in/cift/cift_products/ET20260917T235404/ET20260917T235404_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