INTEGRAL detection of a long powerful burst from SLX1735-269

Abstract

We present results of analysis of a bursting behavior of a low mass X-ray binary system SLX 1735-269 during INTEGRAL observations of the Galactic Center region in 2003. There were detected 6 type I X-ray bursts in total, with one being much longer and more powerful then others. A strong dependence of the bursts recurrence time on the mass accretion rate is observed, that is likely caused by the change in the burning regime. The long burst demonstrated a photospheric radius expansion. We discuss possible scenarios of this long burst and show that it is unlikely a carbon burning flash and rather a burst of large pile of hydrogen and helium accelerated by electron capture processes in a dense accumulated layer.