X-ray and Optical Images of M31
The optical image from the Digitized Sky Survey shows the Andromeda Galaxy, otherwise known as M31. The first Chandra image shows a small region in the center of Andromeda taken before January 2006 and the second shows the same region taken after January 2006. Before 2006, three X-ray sources are clearly visible, including one faint source close to the center of the image. After 2006, a fourth source, called M31*, appears just below and to the right of the central source, produced by material falling onto the supermassive black hole in M31.
(Credit: X-ray (NASA/CXC/SAO/Li et al.), Optical (DSS))

M31 with Scale Bar
(Credit: X-ray (NASA/CXC/SAO/Li et al.), Optical (DSS)