||An astronomical object whose dominant mechanism of radiation is through X-ray emission.
X-ray sources contain an extremely hot gas at temperatures from 10^6 to 10^8 K. They
are generated by various physical processes involving high energies, such as accretion
on to a compact object, shock waves from supernovae, stellar winds, hot gas in stellar
coronae, or hot spaces between galaxies in a cluster. The first celestial X-ray source,
after the Sun, to be detected was Scorpius X-1 by means of rocket flight.