Image: Lockman Hole

Description: The Chandra mosaic of a region of the sky known as the Lockman Hole (named after astronomer Felix Lockman, who discovered that this region of the Galaxy is almost free of absorption by neutral hydrogen gas) shows hundreds of X-ray sources. The high spatial resolution of Chandra allowed for the identification of many supermassive black holes in this image. The Lockman Hole data and two other surveys with Chandra and the Hubble Space Telescope have provided a reasonably accurate census of supermassive black holes in the Universe. Astronomers have used this census to study the rate at which these enormous black holes grow by pulling in gas from their surroundings.
Title: Lockman Hole
Credit: CHANDRA X-ray Observatory CXC Operated for NASA by SAO, url=http://chandra.harvard.edu/photo/2005/bhlock/
Author: X-ray: NASA/CXC/U. Wisconsin/A.Barger et al.; Illustrations: NASA/CXC/M.Weiss
Permission: Images from NASA usually are free of copyright.
Usage Terms: Public domain
License: Public domain
Attribution Required?: No