Researchers found 84 so-called hypersoft X-ray sources in M101, Messier 31, and four elliptical galaxies. This newly-discovered class of objects give off very low-energy X-rays and likely high levels of ultraviolet light. Their existence may help explain questions around Type Ia supernova explosions and the intergalactic medium. These images of the face-on spiral galaxy M101 show X-ray data from Chandra and an optical image from the Hubble Space Telescope.图:NASA · NASA Image and Media Guidelines