Chandra and Hubble Study of a New Transient X-ray Source in M31

Abstract

We present X-ray and optical observations of a new transient X-ray source in M31 first detected 23-May-2004 at R.A.=00:43:09.940 +/- 0.65'', Dec.=41:23:32.49 +/- 0.66''. The X-ray lightcurve shows two peaks separated by several months, reminiscent of many Galactic X-ray novae. The location and X-ray spectrum of the source suggest it is a low mass X-ray binary (LMXB). Follow-up HST ACS observations of the location both during and after the outburst provide a high-confidence detection of variability for one star within the X-ray position error ellipse. This star has $\Delta$B ~ 1 mag, and there is only a ~1% chance of finding such a variable in the error ellipse. We consider this star a good candidate for the optical counterpart of the X-ray source. The luminosity of this candidate provides a prediction for the orbital period of the system of 2.3${}_{-1.2}^{+3.7}$ days.

arXiv comment17 pages, 3 figures, 4 tables, accepted for publication in ApJ

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Cited by in corpus (8)

• The deep XMM-Newton Survey of M 31
• A study of the population of LMXBs in the bulge of M31
• Time variability of X-ray sources in the M 31 centre field
• X-ray source variability study of the M 31 central field using Chandra HRC-I
• Comparing Chandra and Hubble in the Northern Disk of M31
• Bright X-ray Transients in M31: 2004 July XMM-Newton Observations
• A Soft X-ray Transient in the M31 Bulge
• Observations of the recurrent M31 transient XMMU~J004215.8+411924 with Swift, Chandra, HST and Einstein