TITLE:   GCN CIRCULAR
NUMBER:  34635
SUBJECT: GRB 230905B: AstroSat CZTI detection
DATE:    23/09/07 08:06:48 GMT
FROM:    Gaurav Waratkar at IIT Bombay <gauravwaratkar@iitb.ac.in>

P. K. Navaneeth (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 230905B which was also detected by GECAM-C (Xiong et al., GCN Circ. 34630), and INTEGRAL/SPI-ACS.

The source was clearly detected in the 20-200 keV energy range. The light curve peaks at 2023-09-05 15:49:37.50 UTC. The measured peak count rate associated with the burst is 186 (+46, -24) counts/s above the background in the combined data of all quadrants, with a total of 1858 (+502, -520) counts. The local mean background count rate was 447 (+2, -3) counts/s. Using cumulative rates, we measure a T90 of 45 (+14, -22) s.

The source was also detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range.

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.

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