Ben Johnson:

Title: Extraordinary Views of Ordinary Galaxies

Abstract: The determination of the star formation rate of galaxies is a primary tool for understanding their assembly. It is important that these determinations are accurate. A combination of the ultraviolet and infrared emission of galaxies traces the presence of young, luminous stars, even in the presence of dust attenuation. Using Spitzer and GALEX data I have determined the global IR and UV luminosities of a large, representative sample of galaxies selected from the SDSS spectroscopic survey. The IR and UV data are compared to optical measures of star formation, both to determine the relative accuracy of the different indicators and to investigate the possibility that this comparison can lead to knowledge about the time-scale of star formation: does star formation take place continuously as gas is gradually exhausted, or do large accretion events lead to bursts of star formation? I will also describe the implications of this comparison for the measurement of star formation at redshift 2-3

In such multiwavelngth comparisons the presence of dust attenuation is the dominant effect that must be accounted for. I use Spitzer IR data in combination with the GALEX UV data to constrain the amount of dust attenuation in these systems and its effect on the observed and derived properties (e.g. color or star formation rate). I will consider the possibility that dust attenuation may be predicted from the global gas surface density and metallicity of galaxies.