A BeppoSAX-WFC viewpoint of new INTEGRAL sources, particularly IGR J17544-2619

Abstract

Of the 21 new sources that INTEGRAL discovered up to Feb. 1, 2004, five were detected with the BeppoSAX Wide Field Cameras at earlier times. IGR J16320-4751 appears to be a persistently active X-ray source which hints at a supergiant Roche-lobe overflowing companion star in this proposed high-mass X-ray binary. IGR J17091-3624 is a transient source that was detected in 1996 and 2001 with a maximum flux of 20 mCrab (2-28 keV). It is either a Be X-ray binary or a low mass X-ray binary transient. IGR J18483-0311 may be a high-mass X-ray binary, because it is located in a region rich of such objects, just like IGR J19140+098. IGR J17544-2619 appears to be a frequently active X-ray source whose hours-long flares, of which WFC detected five, are reminiscent of the stellar black hole source V4641 Sgr. We discuss this source in detail.