CXOM31 004211.37+41042551, a new X-ray transient discovered with Chandra
ATel #3645; R. Barnard (CfA), M. R. Garcia (CfA), S. S. Murray (Johns Hopkins)
on 12 Sep 2011; 17:43 UT
Distributed as an Instant Email Notice Transients
Credential Certification: Robin Barnard (rbarnard@cfa.harvard.edu)
Subjects: X-ray, Binary, Black Hole, Transient
A new transient X-ray source was discovered in the 2011 August 26 Chandra ACIS observation of M31 (OBSID 12973), at RA = 00:42:11.37 DEC = +41:04:25.51. This system is likely to be a low mass X-ray binary with a black hole primary. The emission spectrum contained ~250 net source counts, and was well described by a power law with photon index 1.4 +/- 0.2, suffering absorption equivalent to 6.7E+20 H atom / cm^2 (chi^2/dof = 11/10). However, an absorbed disk blackbody model also provides an acceptable fit, with an inner disk temperature of 1.5 +/- 0.5 keV (chi^2/dof = 15/10). The power law fit is better than the disk blackbody fit, suggesting that the system is in the black hole low state, although we cannot rule out the high state. The 0.3-10 keV luminosity from the power law fit was 7.3 +/- 1.5 E+37 erg/s. Observations with the HST/ACS in the F435W filter are pending.
