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GCN Circular 33779

Subject
GRB 230512A: AstroSat CZTI detection
Date
2023-05-12T14:20:03Z (a year ago)
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 GRB 230512A which was also detected by Fermi GBM (Fermi GBM Team, GCN Circ. 33778Not found
 
 
).

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 2023-05-12 06:27:47.85 UTC. The measured peak count rate associated with the burst is 2471 (+338, -103) counts/s above the background in the combined data of all quadrants, with a total of 3279 (+219, -231) counts. The local mean background count rate was 490 (+10, -12) counts/s. Using cumulative rates, we measure a T90 of 2.44 (+0.17, -0.13) s. In the preliminary analysis, we find 317 Compton events associated with this event.

The source 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 2023-05-12 06:27:47.85 UTC. The measured peak count rate associated with the burst is 2735 (+109, -115) counts/s above the background in the combined data of all quadrants, with a total of 6183 (+356, -346) counts. The local mean background count rate was 1667 (+6, -9) counts/s. We measure a T90 of 2.82 (+2.02, -0.27) s from the cumulative Veto light curve.

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