NGC 253: X Ray Zoom . ... X-ray Image: SAO , CXC , NASA ; Optical Image: ESO Explanation: Astronomers now report that Chandra X-ray Observatory observations of galaxies known to be frantically forming stars show that these galaxies also contain luminous x-ray sources -- thought to be intermediate mass black holes and immense clouds of superheated gas. ... Much more luminous than black hole binary star systems in our own galaxy, these extreme x-ray sources may be gravitating toward NGC 253's center. ...