Ten years of IBAS

Abstract

The INTEGRAL Burst Alert System (IBAS) has been developed to detect and locate in real time the gamma-ray bursts (GRBs) serendipitously observed by INTEGRAL. The IBAS software runs automatically at the INTEGRAL Science Data Centre (ISDC), where the satellite data are received with a delay of only a few seconds. The sky coordinates of the GRBs occurring in the field of view of the IBIS instrument are distributed via Internet in real time. The localizations have a typical uncertainty radius of 2 arcmin (90% c.l.) and in most cases are available within a few tens of seconds after the beginning of the GRB. In ten years of operations IBAS has localized about 90 GRBs, most of which in near real time, and distributed alerts also for other kinds of astrophysical transient events, such as type I bursts from low mass X-ray binaries, flares and bursts from magnetars, and outbursts of Galactic transients. IBAS also provides the light curves for the GRBs detected with the anti-coincidence shield of the SPI instrument. Here I summarize the main properties of the GRBs detected in the field of view of IBIS during the first ten years of the INTEGRAL mission.