TITLE: GCN CIRCULAR NUMBER: 39360 SUBJECT: GRB 250216A: AstroSat CZTI detection DATE: 25/02/18 05:55:34 GMT FROM: Gaurav Waratkar at IIT Bombay gauravwaratkar@iitb.ac.in
M. Tembhurnikar (IUCAA), G. Waratkar (IITB), J. Joshi (IUCAA), 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 a faint detection of GRB 250216A which was also detected by Fermi/GBM (Fermi-GBM Team, GCN Circ. 39347). Inspection of INTEGRAL/SPI-ACS data also showed the detection of the burst.
Due to the likely hard nature of the burst, we don’t see any detection in the CZT detectors (20-200 keV).
The source was faintly detected in the CsI anticoincidence (Veto) detector in the 100-500 keV energy range and we see only the initial short spike from the Fermi/GBM lightcurve. The light curve peaks at 2025-02-16 20:20:42.4 UTC. The measured peak count rate associated with the burst is 273 (+63, -65) counts/s above the background in the combined data of all quadrants, with a total of 399 (+207, -194) counts. Due to the intrinsic 1 s binning of veto data, we cannot reliably estimate a T90 from it.
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
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