GCN Circular 43508
Subject
GRB 260120A: AstroSat CZTI detection
Event
Date
2026-01-24T11:33:06Z (2 days ago)
From
Anuraag Arya at IIT Bombay <aryaanuraag910@gmail.com>
Via
Web form
Harsha K. H. (IUCAA), M. Tembhurnikar (IUCAA), S. Salunke (IUCAA), A. Arya (IITB), A. Goyal (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 260120A which was also detected by Fermi GBM (Fermi GBM Team, GCN Circ. 43467), and GECAM-B (Guo et al., GCN Circ. 43505).
The source was clearly detected in the CZT detectors in the 20-200 keV energy range. The light curve peaks at 2026-01-20 04:01:55.50 UTC. The measured peak count rate associated with the burst is 264 (+132, -24) counts/s above the background in the combined data of three quadrants (out of four), with a total of 345 (+83, -77) counts. The local mean background count rate was 189 (+3, -7) counts/s. Using cumulative rates, we measure a T90 of 3.1 (+1.1, -0.8) s.
The source was also clearly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2026-01-20 04:01:54.79 UTC. The measured peak count rate associated with the burst is 246 (+62, -64) counts/s above the background in the combined data of all quadrants, with a total of 625 (+185, -199) counts. The local mean background count rate was 1120 (+5, -6) counts/s. We measure a T90 of 4.2 (+1.3, -1.5) 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