[vsnet-grb-info 26908] GRB 201209A: AstroSat CZTI detection

[GCN Circulars]

TITLE:   GCN CIRCULAR
NUMBER:  29011
SUBJECT: GRB 201209A: AstroSat CZTI detection
DATE:    20/12/09 12:05:42 GMT
FROM:    Gaurav Waratkar at IIT Bombay  <gauravwaratkar24 at gmail.com>

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 201209A, which
was also detected by Swift-BAT (GCN #29005).

The source was clearly detected in the 20-200 keV energy range. The
light curve showed multiple peaks of emission with the strongest peak
at 2020-12-09 05:44:56.500 UT. The measured peak count rate associated
with the burst is 456 (+51, -54) cts/s above the background in the
combined data of four quadrants, with a total of 3215 (+719, -885)
cts. The local mean background count rate was 557 (+4, -3) cts/s.
Using cumulative rates, we measure a T90 of 23 (+14, -12) s.

It was also 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 2020-12-09
05:44:56.336 UT. The measured peak count rate is 697 (+81, -89) cts/s
above the background in the combined Veto data of four quadrants, with
a total of 4866 (+1506, -1667) cts. The local mean background count
rate was 1856 (+6, -7) cts/s. We measure a T90 of 25 (+26, -15) 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, ISAC, IUCAA,
SAC and PRL. The Indian Space Research Organisation funded, managed
and facilitated the project.