Optical Constraints on an X-ray Transient Source in M31
Abstract
We have detected a transient X-ray source in the M31 bulge through a continuing monitoring campaign with the Chandra ACIS-I camera. The source was detected at R.A.=00:42:33.428 +/- 0.11'', Dec.=+41:17:03.37 +/- 0.11'' in only a single observation taken 2004 May 23. Fortuitous optical HST/ACS imaging of the transient location prior to the X-ray outburst, along with follow-up HST/ACS imaging during and after the outburst, reveals no transient optical source brighter than B (equivalent) = 25.5. The location of the source and its X-ray properties suggest it is a low mass X-ray binary (LMXB). Assuming the transient is similar to many Galactic X-ray novae, the X-ray luminosity of (3.9 +/- 0.5) X 10 erg s and the upper-limit on the optical luminosity provide a prediction of <1.6 days for the orbital period of the binary system.
Cite
@article{arxiv.astro-ph/0506312,
title = {Optical Constraints on an X-ray Transient Source in M31},
author = {Benjamin F. Williams and Michael R. Garcia and Frank A. Primini and Jeffrey E. McClintock and Stephen S. Murray},
journal= {arXiv preprint arXiv:astro-ph/0506312},
year = {2009}
}
Comments
15 pages, 3 figures, accepted for publication in ApJ