page_title: Astrophysical X-ray source
section_title: Corona Borealis
hierarchical_section_title: Astrophysical X-ray source / Celestial X-ray sources / Corona Borealis
caption_attribution_description: English: X-ray image of galaxy cluster Abell 2412
context_page_description: Astrophysical X-ray sources are astronomical objects with physical properties which result in the emission of X-rays.
  There are a number of types of astrophysical objects which emit X-rays, from galaxy clusters, through black holes in active galactic nuclei to galactic objects such as supernova remnants, stars, and binary stars containing a white dwarf, neutron star or black hole. Some solar system bodies emit X-rays, the most notable being the Moon, although most of the X-ray brightness of the Moon arises from reflected solar X-rays. A combination of many unresolved X-ray sources is thought to produce the observed X-ray background. The X-ray continuum can arise from bremsstrahlung, either magnetic or ordinary Coulomb, black-body radiation, synchrotron radiation, inverse Compton scattering of lower-energy photons by relativistic electrons, knock-on collisions of fast protons with atomic electrons, and atomic recombination, with or without additional electron transitions.
  Furthermore, celestial entities in space are discussed as celestial X-ray sources.
context_section_description: The galaxy cluster Abell 2142 emits X-rays and is in Corona Borealis. It is one of the most massive objects in the universe.
caption: Chandra X-ray Observatory image of the galaxy cluster Abell 2142.
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