universetoday.com
Massive Gas Halos Surround Most Galaxies
ESA's XMM-Newton observatory has turned up hot gaseous halos around several spiral galaxies. These ghostly veils have been seen surrounding "starburst galaxies", which are going through a tremendous amount of star formation - but not around the more common kinds of galaxies. Unlike a starburst galaxies, which concentrates their halos, regular galaxies will have simmering star formation stretching across them entirely. These halos can contain up to 10 million solar masses of gas.
Fraser Cain