INTEGRAL high energy monitoring of the X-ray burster KS 1741-293

TL;DR

This paper reports long-term INTEGRAL observations of the X-ray burster KS 1741-293, confirming its transient nature, analyzing its broad-band spectrum, and classifying it among hard-tailed X-ray bursters.

Contribution

It provides the first wide-band spectral analysis of KS 1741-293 and confirms its classification as a hard-tailed X-ray burster based on recent INTEGRAL data.

Findings

KS 1741-293 is transient in soft and hard X-ray bands.

The spectrum from 5 to 100 keV fits a two-component model.

Confirmed the bursting nature of KS 1741-293.

Abstract

KS 1741-293, discovered in 1989 by the X-ray camera TTM in the Kvant module of the Mir space station and identified as an X-ray burster, has not been detected in the hard X band until the advent of the INTEGRAL observatory. Moreover this source has been recently object of scientific discussion, being also associated to a nearby extended radio source that in principle could be the supernova remnant produced by the accretion induced collapse in the binary system. Our long term monitoring with INTEGRAL, covering the period from February 2003 to May 2005, confirms that KS 1741-293 is transient in soft and hard X band. When the source is active, from a simultaneous JEM-X and IBIS data analysis, we provide a wide band spectrum from 5 to 100 keV, that can be fit by a two component model, a multiple blackbody for the soft emission and a Comptonized or a cut-off power law model for the hard component. Finally, by the detection of two X-ray bursters with JEM-X, we confirm the bursting nature of KS 1741-293, including this source in the class of the hard tailed X-ray bursters.