3C 295: X-rays From A Giant Galaxy

Explanation: Did this galaxy eat too much? Five billion light-years away, the giant elliptical galaxy 3C295 is a prodigious source of energy at radio wavelengths . Bright knots of X-ray emission are also seen at the center of this false-color Chandra Observatory image of the region. The X-ray and radio emission are believed to be the result of an explosive event triggered when too much material flowed into a supermassive black hole at the heart of the giant galaxy. Additionally, the Chandra picture beautifully reveals an extensive cloud of 50 million degree gas surrounding 3C295 . Embedded in the cloud is a cluster of about 100 galaxies, too cool to be seen in the X-ray picture. About two million light-years across, the X-ray hot cloud itself contains enough material to create another 1,000 galaxies or so making the cluster and cloud among the most massive objects in the Universe. However, X-ray data indicate that there is still not enough observed mass to hold the cloud and cluster together gravitationally, suggesting the presence of large amounts of dark matter .