Ultraluminous X-Ray Source

Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. An ultra-luminous X-ray source (ULX) is an astronomical source of X-rays that is less luminous than an active galactic nucleus but is more consistently luminous than any known stellar process (< 1039 erg/s, or 1032 watts), assuming that it radiates isotropically (the same in all directions). Typically there is about one ULX per galaxy in galaxies which host ULXs, but some galaxies contain many ULXs. The Milky Way does not contain a ULX.