GCN Circular 44380
Subject
GRB 260421A: AstroSat CZTI detection
Event
Date
2026-04-21T15:59:15Z (2 days ago)
From
Anuraag Arya at IIT Bombay <aryaanuraag910@gmail.com>
Via
Web form
M. Tembhurnikar (IUCAA), S. Salunke (IUCAA), Harsha K. H. (IUCAA), A. Arya (IITB), A. Goyal (IITB), 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 GRB 260421A which was also detected by Fermi GBM (Fermi GBM Team, GCN Circ. 44358).
The source was detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range. The light curve peaks at 2026-04-21 02:12:43.91 UTC. The measured peak count rate associated with the burst is 251 (+66, -70) counts/s above the background in the combined data of all quadrants, with a total of 267 (+133, -138) counts. The local mean background count rate was 1340 (+8, -10) counts/s. Due to the intrinsic 1s binning of Veto data, we cannot reliably estimate T90 for this burst.
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