M31 X-ray image

X-ray count rate image of M31 derived from the data of the second survey and with a technique applied to point out single point sources. One image pixel correspondsto 21.5" x 21.5" at the sky. Only photons within the energy range of 0.5 to 2.0 keV and with offax angles <= 20' had been used. The ellipse sketches the D25-size of M31.