Chandra Release - April 6, 2005

Visual Description: SMG 123616.1+621513

The image shows an illustration and inset X-ray image from Chandra of two merging galaxies. Observed in the Chandra Deep Field-North at a distance of 11 billion light years is SMG 123616.1+621513.  The artist's illustration shows two young galaxies in the process of merging with a thin bridge of material connecting them. Both spiral-like galaxies appear to have a similar color palette, dominated by shades of pale gold-pink on a black background. However, upon closer inspection, the galaxy on the lower right side has a soft pink core, with the galaxy on the upper left side having a soft blue core.  The merger has triggered a prodigious burst of star formation and is providing fuel for the growth of the galaxies' central supermassive black holes. The inset shows a Chandra image of two central black holes in merging galaxies. Although the black holes appear to be very close in the image with one colored soft blue-green and the other soft pink, they are actually about 70,000 light years apart. The different colors in the image are due to differences in X-ray absorption by gas and dust around the black holes with blue indicating more absorption than red. Observations indicate that many adolescent merging galaxies and their central black holes underwent a phenomenal spurt of growth 10 billion to 12 billion years ago. This growth spurt may have set the stage for the appearance of quasars, distant galaxies that contain the largest and most active black holes in the Universe.