TITLE:   GCN CIRCULAR
NUMBER:  32990
SUBJECT: GRB 221126A: AstroSat CZTI detection
DATE:    22/11/28 13:58:27 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

M. Dixit (IITB), V. Prasad (IUCAA), 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 long GRB 221126A which was 
also detected by Fermi-GBM (GCN Cir. 32985) and Swift/BAT-GUANO (GCN 
Cir. 32987).

The source was clearly detected in the 20-200 keV energy range. The 
light curve peaks at 2022-11-26 13:07:28.950 UTC. The measured peak 
count rate associated with the burst is 590.6 (+51.2, -55.0) counts/s 
above the background in the combined data of all quadrants, with a total 
of 2093 (+254, -271) counts. The local mean background count rate was 
433.4 (+2.7, -3.0) counts/s. Using cumulative rates, we measure a T90 of 
4.89 (+4.45, -1.03) s.

It was also clearly detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range. The light curve peaks at 2022-11-26 
13:07:28.640 UTC. The measured peak count rate is 663.6 (+72.1, -79.1) 
counts/s above the background in the combined Veto data of all 
quadrants, with a total of 1770 (+234, -259) counts. The local mean 
background count rate was 1410.0 (+4.9, -5.4) counts/s. We measure a T90 
of 4.18 (+1.11, -1.24) s from the cumulative Veto light curve.

CZTI GRB detections are reported regularly on the payload site at 
http://astrosat.iucaa.in/czti/?q=grb. 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.