M31 deepest Chandra catalogue of point sources

Using 133 publicly available Chandra ACIS-I/S observations totalling ~1Ms, we detected 795 X-ray sources in the bulge, north-east, and south-west fields of M31, covering an area of ~=0.6deg^2^, to a limiting unabsorbed 0.5-8.0keV luminosity of ~10^34^erg/s. In the inner bulge, where exposure is approximately constant, X-ray fluxes represent average values because they were determined from many observations over a long period of time.

Similarly, our catalogue is more complete in the bulge fields since monitoring allowed more transient sources to be detected. The catalogue was cross-correlated with a previous XMM-Newton catalogue of M31's D_25_ isophote consisting of 1948 X-ray sources, with only 979 within the field of view of our survey. We found 387 (49 per cent) of our Chandra sources (352 or 44 per cent unique sources) matched to within 5 arcsec of 352 XMM-Newton sources.