The Galaxy Evolution Explorer - Early Data

Abstract

We report on early data from the Galaxy Evolution Explorer (GALEX), a NASA Explorer Mission launched on April 28, with a nominal mission start of June 19. GALEX is performing the first space UV sky-survey, including imaging and grism surveys in two bands (1350–1750 Å and 1750–2800 Å). The surveys include an all-sky imaging survey (limit AB∼20–21), a medium imaging survey of 1000 sq. deg (limit AB∼23.5), a deep imaging survey of 100 deg2 (limit AB∼25.5), and a nearby galaxy survey. Spectroscopic grism surveys (R=100–300) will be performed with various depths and sky coverage. Many targets overlap existing or planned surveys, including SDSS, DEEP, NOAODWS, VIRMOS, SWIRE, SINGS, SIRTF-GTO, Chandra, and HST/ACS. We will use the measured UV properties of local galaxies, along with corollary observations, to calibrate the UV-global star formation rate relationship in galaxies. We will apply this calibration to distant galaxies discovered in the deep imaging and spectroscopic surveys to map the history of star formation in the universe over the redshift range 0<z<2. The GALEX mission will include a Guest Investigator program for primary observations and supporting data analysis. This will support a wide variety of investigations made possible by the first UV sky survey.