TITLE: GCN CIRCULAR NUMBER: 37560 SUBJECT: GRB 240918A and GRB 240918B : INTEGRAL SPI ACS LIGHT CURVE DATE: 24/09/19 23:14:33 GMT FROM: Devraj Pawar at R. J. College, Mumbai - 86, India <devrajdp@gmail.com> Devraj Pawar (R. J. College, Mumbai-86, India) on behalf of a collaboration studying transients. GRB 240918A and GRB 240918B were reported by the Fermi GBM team in GCN 37549 and GCN 37558 respectively. We analyzed the INTEGRAL SPI ACS data around the T0 given in GCN 37549 and detected two peaks separated by ~108 seconds in the light curve. These events occur at the times reported in GCN 37549 and GCN 37558. SPI ACS is sensitive above 80 keV : the peak of the first burst is at ~3550 counts/s and peak count rate of the second burst is 3800 counts/s. The steady count rate preceding the events is around 3350 counts/s. The count rate is affected by the instruments orientation with respect to the direction of the sources and hence the relative intensity of the two bursts cannot be compared with the analysis done so far. GRB 240918A is not visually detected with the 0.05 s resolution of the INTEGRAL SPI ACS, hence we time averaged the light curve. The light curves at various time resolutions and the burst profiles are given in the link below and any further analysis will be shared on the same link : [GRB 240918A and GRB 240918B : INTEGRAL SPI ACS LIGHT CURVES](https://docs.google.com/document/d/15b887kxPSdQVyT9NLfZZzb8XMLhijewiSY8KHXPT...) This work is based on observations with INTEGRAL, an ESA project with instruments and a science data center funded by ESA member states (especially the PI countries: Denmark, France, Germany, Italy, Switzerland, Spain), and with the participation of Russia and the USA. The SPI-ACS detector system has been provided by MPE Garching/Germany. View this GCN Circular online at https://gcn.nasa.gov/circulars/37560. --- To unsubscribe, open this link in a web browser: https://gcn.nasa.gov/unsubscribe/eyJhbGciOiJIUzI1NiJ9.eyJlbWFpbCI6InZzbmV0LW...