Recent star formation in nearby galaxies from Galaxy Evolution Explorer imaging:: M101 and M51

The Galaxy Evolution Explorer (GALEX) Nearby Galaxies Survey is providing deep far-UV and near-UV imaging for a representative sample of galaxies in the local universe. We present early results for M51 and M101, from GALEX UV imaging and Sloan Digital Sky Survey optical data in five bands. The multiband photometry of compact stellar complexes in M101 is compared to population synthesis models, to derive ages, reddening, reddening-corrected luminosities, and current/initial masses. The GALEX UV photometry provides a complete census of young compact complexes on a approximate to160 pc scale. A galactocentric gradient of the far-UV/near-UV color indicates younger stellar populations toward the outer parts of the galaxy disks, the effect being more pronounced in M101 than in M51.