Chandra Release - March 22, 2005

Visual Description: M74

 The X-ray and optical composite Image shows a ULX (Ultraluminous X-ray Source) in the galaxy M74.  There is a large, spiral-shaped galaxy facing the viewer with a very bright white core.  The color of the galaxy is a pale greenish-blue with red dots scattered on it as if it has measles.  Chandra X-ray Observatory data (red) with optical (green-blue & white) also highlights the ULX shown in a small box at about 11 o’clock. ULX sources are distinctive because they radiate 10 to 1000 times more X-ray power than neutron stars and stellar mass black holes. Chandra observations of this ULX have provided evidence that its X-radiation is produced by a disk of hot gas swirling around a black hole with a mass of about 10,000 Suns.