Chandra detection of a hot gaseous corona around the edge-on galaxy NGC 4631

We present a Chandra X-ray observation that shows, unambiguously for the fi rst time, the presence of a giant diffuse X-ray-emitting corona around the edge-on disk galaxy NGC 4631. This corona, with a characteristic thermal te mperature of (2-7) x 10(6) K, extends as far as 8 kpc away from the galacti c plane. The X-ray morphology resembles the radio halo of the galaxy, indic ating a close connection between outflows of hot gas, cosmic rays, and the magnetic field from the galactic disk. Enhanced diffuse X-ray emission is a pparently enclosed by numerous H alpha -emitting loops blistered out from t he central disk of the galaxy, as is evident in a comparison with our deep Hubble Space Telescope imaging.