X-raying a galactic jet set

Science News, Jan 19, 2008 by Ron Cowen

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Jets of energetic particles shoot out from a supermassive black hole in the deepest X-ray image ever taken of the galaxy Centaurus A, 11 million light-years from Earth. In this 199-hour portrait, recorded with NASA's Chandra x-ray Observatory, red denotes the lowest-energy X rays, blue the highest. The image shows new details within a 13,000 light-year-long jet (pointing to the upper left) and a shorter, oppositely directed counterpart. The X rays come from electrons whipping around strong magnetic fields, but the emissions would fade if the electrons were not continually re-energized. Clumps in the inner parts of the jets may mark places where the jets plow into gas clouds or stars, generating shock waves that reboost the electrons. Many of the pointlike X-ray sources are small, stellar-mass black holes that feed off normal companion stars, Gregory sivakoff of the Ohio State University in Columbus and his colleagues reported last week in Austin, Texas, at a meeting of the American Astronomical Society.