Chandra Observations of the Faintest Low-Mass X-ray Binaries
Abstract
There exists a group of persistently faint galactic X-ray sources that, based on their location in the galaxy, high L_x/L_opt, association with X-ray bursts, and absence of low frequency X-ray pulsations, are thought to be low-mass X-ray binaries (LMXBs). We present results from Chandra observations for eight of these systems: 4U 1708-408, 2S 1711-339, KS 1739-304, SLX 1735-269, GRS 1736-297, SLX 1746-331, 1E 1746.7-3224, and 4U 1812-12. Locations for all sources, excluding GRS 1736-297, SLX 1746-331, and KS 1739-304 (which were not detected) were improved to 0.6" error circles (90% confidence). Our observations support earlier findings of transient behavior of GRS 1736-297, KS 1739-304, SLX 1746-331, and 2S 1711-339 (which we detect in one of two observations). Energy spectra for 4U 1708-408, 2S 1711-339, SLX 1735-269, 1E 1746.7-3224, and 4U 1812-12 are hard, with power law indices typically 1.4-2.1, which are consistent with typical faint LMXB spectra.
Keywords
Cite
@article{arxiv.astro-ph/0307045,
title = {Chandra Observations of the Faintest Low-Mass X-ray Binaries},
author = {Colleen. A. Wilson and Sandeep K. Patel and Chryssa Kouveliotou and Peter G. Jonker and Michiel van der Klis and Walter H. G Lewin and Tomaso Belloni and Mariano Mendez},
journal= {arXiv preprint arXiv:astro-ph/0307045},
year = {2009}
}
Comments
15 pages, 3 figures. Accepted by ApJ