GALEX: Mapping the Hidden Side of Galaxy Evolution and the UV Universe
Chris Martin



The Galaxy Evolution Explorer (GALEX), a NASA Small Explorer mission launched in 2003, continues its surveys of the ultraviolet sky. GALEX surveys have supported the following galaxy evolution investigations: calibrating UV as a star formation rate tracer, using wide and deep surveys to measure star formation history, studying the evolution of dust extinction and metallicity, selecting and analyzing galaxies in transitory states, finding local analogs to Lyman Break Galaxies, and probing and time-dating star formation in a wide variety of physical regimes. Ultimately the data will be combined with other multiwavelength surveys to connect star formation history and galaxy evolutionary paths to the properties and assembly history of their dark matter halos, to the content and evolution of their gas reservoirs, to the driving gas flows from and to the intergalactic medium, and to the central black holes those galaxies host. GALEX has proven that the UV is an ideal band to find and map star formation in low mass, low density, and unevolved gas. In the final phase of the mission we are observing regions of the galaxy and Magellenic Clouds that were previously proscribed by brightness limits. GALEX has demonstrated the power of surveys in a new electromagnetic band by triggering many discoveries and new insights about the UV universe, discoveries that will continue long after the mission has ended.