The UV (GALEX) and FIR (ASTRO-F) All Sky Surveys: the measure of the dust extinction in the local universe

Before the end of 2002 will be launched the GALEX satellite (a NASA/SMEX project) which will observe all the sky in Ultraviolet (UV) through filters at 1500 and 2300 A down to m(AB) 21. In 2004 will be launched the ASTRO-F satellite which will perform an all sky survey at Far-Infrared (FIR) wavelengths. The cross-correlation of both surveys will lead to very large samples of galaxies for which FIR and UV fluxes will be available. Using the FIR to UV flux ratio as a quantitative tracer of the dust extinction we will be able to measure the extinction in the nearby universe (z<0.2) and to perform a statistically significant analysis of the extinction as a function of galactic properties. Of particular interest is the construction of pure FIR and UV selected samples for which the extinction will be measured as templates for the observation of high redshift galaxies.