[vsnet-grb-info 27265] GRB 210126A: AstroSat CZTI detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29368
SUBJECT: GRB 210126A: AstroSat CZTI detection
DATE:    21/01/29 07:39:06 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar at iitb.ac.in>

D. Nadella (NITK), G. Waratkar (IITB), A. Vibhute (IUCAA), S. Gupta
(IUCAA), P. Sawant (IUCAA), V. Bhalerao (IITB), D. Bhattacharya (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,
2020, arxiv:2011.07067) showed detection of a long GRB 210126A, which
was also detected by Fermi-GBM (GCN #29354) and GECAM-B (GCN #29356). 

The source was detected in the 20-200 keV energy range in three
quadrants (Quadrant A, C, and D). Quadrant D was noisy, and we excluded
it from further analysis. The light curve showed multiple peaks of
emission with the strongest peak at 2021-01-26 10:00:07 UT. The measured
peak count rate associated with the burst is 56 (+9, -10) cts/s above
the background in the combined data of two quadrants, with a total of
1039 (+412, -454) cts. The local mean background count rate was 248 (+1,
-1) cts/s. Using cumulative rates, we measure a T90 of 67 (+41, -55) s.
These large error bars arise from the presence of a weak second peak
whose association with the burst is ambiguous in our data. 

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, ISAC, IUCAA, SAC
and PRL. The Indian Space Research Organisation funded, managed and
facilitated the project.