TITLE: GCN CIRCULAR NUMBER: 38965 SUBJECT: GRB 250116A: INTEGRAL/SPI-ACS and PICsIT detection DATE: 25/01/16 22:28:51 GMT FROM: Aishwarya L Thakur at INAF-IAPS, Rome aishth@outlook.com
Patrizia Barria(a,b), Giulia Gianfagna(a), James Craig Rodi(a), Aishwarya Linesh Thakur(a), Lorenzo Natalucci(a,b), Luigi Piro(a) report:
GRB 250116A was discovered by Fermi/GBM (GCN 38962, seen also by Fermi/LAT GCN 38963) at time 2025-01-16T12:33:59.53 (UTC) with a duration of 16 s. We searched for any corresponding counterpart in the INTEGRAL/SPI-ACS and IBIS/PICsIT data.
In a SPI/ACS light curve above 80 keV, we find a pulse temporally coincident with the GBM detection having an approximate duration of ~ 15 sec. This pulse is also seen in the PICsIT lightcurve above 212 keV, with a similar duration.
The approximate peak count rate in SPI/ACS is 80,000 cts/s for E>80 keV, over a median background rate of 65,000 cts/s.
After the GRB spike, we note that there is a second, stronger pulse in the light curves of both instruments. The association of this pulse to the GRB at this moment is unclear and is under investigation.
This work is based on observations with INTEGRAL, an ESA project with instruments and a science data centre funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, and Spain), and with the participation of Russia and the USA. The SPI-ACS detector system has been provided by MPE Garching/Germany.
----- (a) INAF/IAPS-Rome (b) ICSC National Research Centre for High-Performance Computing
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