The transient neutron star X-ray binary KS 1741-293 in outburst and quiescence

Abstract

KS 1741-293 is a transient neutron star low-mass X-ray binary that is located at an angular distance of ~20' from the Galactic center. We map out the historic activity of the source since its discovery in 1989, characterize its most recent X-ray outbursts observed with Swift (2007, 2008, 2010, and 2011), and discuss its quiescent X-ray properties using archival Chandra data. KS 1741-293 is frequently active, exhibiting outbursts that typically reach a 2-10 keV luminosity of Lx~1E36 (D/6.2 kpc)^2 erg/s and last for several weeks-months. However, Swift also captured a very short and weak accretion outburst that had a duration of <4 days and did not reach above Lx~5E34 (D/6.2 kpc)^2 erg/s. The source is detected in quiescence with Chandra at a 2-10 keV luminosity of Lx~2.5E32 (D/6.2 kpc)^2 erg/s.