Samir Salim
UCLA

Shedding UV Light on Galaxy Evolution

Driven by vast advances in the observational and computational 
capabilities, the study of the formation and evolution of galaxies has 
entered a new phase during the last decade. While getting as close to 
the epoch of galaxy formation is very exciting, studies at low to 
intermediate redshifts are invaluable for putting together the pieces of 
the galaxy evolution puzzle. Tracing the UV light of a large number of 
star-forming galaxies provides the most efficient way to map galaxy 
evolution at z<1. GALEX satellite is performing the first ever UV 
survey. Besides the shallow all-sky survey, it observes the SDSS 
footprint, and performs targeted deep observations. By combining the UV 
and optical photometry, and performing the Bayesian SED fitting, I have 
accurately determined star formation rates, extinctions and stellar 
masses for tens of thousands of galaxies at 0<z<0.2. These properties 
reveal the star-formation history of: normal star-forming galaxies, 
massive disk galaxies that are shutting down their star formation, 
early-type galaxies that underwent recent star formation, and 
curiosities such as local analogs to Lyman Break Galaxies. At higher 
redshifts, by combining GALEX and DEEP2 data, I study the evolution of 
the star-formation up to z~1.4. By comparing the UV-based star formation 
rates to those obtained with Spitzer, I can place constraints on the 
"obscured" star formation that is believed to be important at higher 
redshifts. Altogether, a picture emerges where the gas exhaustion, AGN 
feedback and dry mergers play an important role in shaping today's galaxies.