Astronomers find massive supply of fresh gas around modern galaxies
(Phys.org)—Galaxies have a voracious appetite for fuel—in this case fresh gas, but astronomers have had difficulty finding the pristine gas that should be falling onto galaxies. Now scientists have provided direct empirical evidence for these gas flows using new observations from the Hubble Space Telescope. Their observations using Hubble's two ultraviolet spectrographs, the Cosmic Origins Spectrograph and the Space Telescope Imaging Spectrograph, show large quantities of cool gas with very low quantities of heavy elements in the gaseous cocoons surrounding modern galaxies. The lack of heavy elements indicates this gas in the "circumgalactic medium" of the galaxies has not been strongly processed through stars. Their work, "The Bimodal Metallicity Distribution of the Cool Circumgalactic Medium at z