Last updated on April 18, 2014 at 14:18 EDT
Lockman Hole
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Lockman Hole

February 16, 2005
This is a deep X-ray Chandra image of the Lockman Hole, a patch of sky that avoids most of the X-ray absorbing gas of the Milky Way. By combining this image with the Chandra Deep Fields, astronomers have been able to construct the most complete black hole census to date of the Universe. Virtually each of these dots - with the red objects usually cooler than the blue objects - represents a supermassive black hole.