XMM-Newton observations of variability in the X-ray binaries of M31:   flares dips and a burst
  The XMM-Newton satellite has made four observations of the core of M31 as part of a survey that will span the entire galaxy. The majority of the X-ray emission is contributed by point sources, chiefly X-ray Binaries (XB). Exciting early results from a survey of time variability in three XMM exposures of the M31 core reveal XB exhibiting Sco X-1 like flaring, dips and a burst. The flaring source in M31 also exhibits variability in intensity and spectral hardness that is characteristic of a Z-source. 
R. Barnard, U. C. Kolb, J. P. Osborne