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The Hard X-ray Background

When X-ray telescopes look at the sky, they see a uniform background of high energy X-rays. However, it is believed that much of this background is the result of individual far away X-ray sources. The Burst Alert Telescope on board Swift is capable of observing this background and resolving finer details than ever before. It is expected that many of the far away sources will be Seyfert type Active Galactic Nuclei that are oriented with the gas and mater filled sides of their galaxies facing us. The gas around Seyfert AGNs normally blocks lower energy photons from reaching us, but higher energy photons like hard X-rays should be detectable with Swift, providing information about the type objects that are responsible for the hard X-ray background.

Imagine the Universe is a service of the High Energy Astrophysics Science Archive Research Center (HEASARC), Dr. Alan Smale (Director), within the Astrophysics Science Division (ASD) at NASA's Goddard Space Flight Center.

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