GCN Circular 44560
Subject
GRB 260511B: AstroSat CZTI detection
Event
Date
2026-05-11T17:32:28Z (4 days ago)
Edited On
2026-05-11T17:39:40Z (4 days ago)
From
Anuraag Arya at IIT Bombay <aryaanuraag910@gmail.com>
Edited By
Judith Racusin at NASA/GSFC <judith.racusin@nasa.gov> on behalf of Anuraag Arya at IIT Bombay <aryaanuraag910@gmail.com>
Via
Web form
A. Arya (IITB), A. Goyal (IITB), M. Tembhurnikar (IUCAA), Harsha K. H. (IUCAA), S. Salunke (IUCAA), 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 260511B which is also detected by Fermi/GBM (Fermi GBM Team, GCN Circ. 44542), SVOM/ECLAIRs (Godet et al., GCN Circ. 44543), and NuSTAR (Waratkar et. al. , GCN Circ. 44556).
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 2026-05-11 11:01:02.99 UTC. The measured peak count rate associated with the burst is 398 (+41, -36) counts/s above the background in the combined data of all quadrants, with a total of 3131 (+342, -481) counts.The local mean background count rate was 282 (+2, -4) counts/s. We measure a T90 of 39 (+3, -2) s from the cumulative CZT light curve.
The source was 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 2026-05-11 11:01:02.74. The measured peak count rate associated with the burst is 1362 (+85, -90) counts/s above the background in the combined data of all quadrants, with a total of 7777 (+766, -805) counts.The local mean background count rate was 1287 (+4, -5) counts/s. We measure a T90 of 37 (+16, -3) 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 data products like interactive and downloadable light curves for this GRB can be found at:
https://astrosat.iucaa.in/cift/cift_products/516193231.75/S516193231.75_details.html
CZTI GRB detections are reported regularly on the payload site at:
http://astrosat.iucaa.in/czti/?q=grb