GCN Circular 32070
Subject
GRB 220514A: AstroSat CZTI detection
Event
Date
2022-05-20T05:16:27Z (3 years ago)
From
Gaurav Waratkar at IIT,Bombay <gauravwaratkar@iitb.ac.in>
R. Gopalakrishnan (IUCAA), V. Prasad (IUCAA), G. Waratkar (IITB), A.
Vibhute (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.,
2021, JApA, 42, 73) showed detection of a long GRB 220514A, which was
also reported by Fermi GBM ( GCN 32028), INTEGRAL (Mereghetti et al.,
GCN 32041) and BALROG ( Biltzinger et al. GCN 32029).
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
2022-05-14 at 12:24:58.50 UT. The measured peak count rate associated
with the burst is 346 (+51, -30) counts/s above the background in the
combined data of four quadrants, with a total of 4001 (+588, -793)
counts. The local mean background count rate was 561 (+2, -3) counts/s.
Using cumulative rates, we measure a T90 of 54 (+9, -5) s.
It was also clearly detected in the CsI anticoincidence (Veto) detector
in the 100-500 keV energy range. The light curve peaks at 2022-05-14 at
12:24:57.99 UT. The measured peak count rate is 401 (+75, -80) counts/s
above the background in the combined Veto data of four quadrants, with a
total of 2095 (+596, -592) counts. The local mean background count rate
was 1935 (+3, -4) counts/s. We measure a T90 of 29 (+4, -8) s from the
cumulative Veto light curve.
This is the 500th GRB detected by AstroSat CZTI since its launch in
September 2015, with an average rate of 75 GRBs/year.
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.