TITLE: GCN CIRCULAR NUMBER: 10898 SUBJECT: GRB 100628A: INTEGRAL SPI-ACS light curve DATE: 10/06/28 18:45:54 GMT FROM: Volker Beckmann at APC V. Beckmann (APC), M. Beck, C. Ferrigno, V. Savchenko, Ievgen Vovk (ISDC), J. Borkowski (CAMK/Torun), D. Götz (CEA/Saclay), S. Mereghetti (INAF/IASF-Milano), and A. von Kienlin (MPE) report on behalf of the INTEGRAL SPI-ACS GRB team: GRB 100628A, detected in Swift/BAT data (Immler et al., GCN 10895; Barthelmy et al., GCN 10896), is detectable also in the data of the SPI Anti-Coincidence System (ACS) on-board INTEGRAL. The SPI-ACS light curve shows the peak of the burst at 2010-06-28T08:16:41 with a maximum count-rate of ~600 counts/50msec. The duration of the GRB is about 0.05 seconds. The SPI-ACS light curves are available (both as images and data files) at http://isdc.unige.ch/Soft/ibas/ibas_acs_web.cgi The light curves, binned at 50 ms, are derived from 91 independent detectors with different lower energy thresholds (mainly between 50 keV and 150 keV) and an upper threshold at about 100 MeV. The ACS response varies as a function of the GRB incident angle. For these reasons we caution that the count rates cannot be easily translated into physical flux units. It is not possible to localize a burst based on the SPI-ACS data. ---------------------------------------------------------------- This message was sent using IMP, the Internet Messaging Program.