TITLE:   GCN CIRCULAR
NUMBER:  33141
SUBJECT: GRB 230101A: AstroSat CZTI detection
DATE:    23/01/03 10:56:14 GMT
FROM:    Gaurav Waratkar at IIT,Bombay  <gauravwaratkar@iitb.ac.in>

P. K. Navaneeth (IUCAA), R. Gopalakrishnan (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 a long GRB 230101A which was 
also detected by Fermi GBM (GCN Circ. 33130).

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 
2023-01-01 02:16:48.5 UTC. The measured peak count rate associated with 
the burst is 183 (+18, -16) counts/s above the background in the 
combined data of all quadrants, with a total of 4974 (+674, -726) 
counts. The local mean background count rate was 435 (+1, -1) counts/s. 
Using cumulative rates, we measure a T90 of 81 (+12, -27) s.

It was also clearly detected in the CsI anticoincidence (Veto) detector 
in the 100-500 keV energy range. The light curve peaks at 2023-01-01 
02:16:42.7 UTC. The measured peak count rate is 830 (+65, -61) counts/s 
above the background in the combined Veto data of all quadrants, with a 
total of 14726 (+2045, -2365) counts. The local mean background count 
rate was 7515 (+5, -5) counts/s. We measure a T90 of 27 (+17, -8) 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.