Reproducing the UVJ Color Distribution of Star-forming Galaxies at 0.5 < z < 2.5 with a Geometric Model of Dust Attenuation

We analyze the distribution of rest-frame U-V and V-J colors for star-forming galaxies at 0.5 < z < 2.5. Using stellar population synthesis, stochastic star formation histories, and a simple prescription for the dust attenuation that accounts for the shape and inclination of galaxies, we construct a model for the distribution of galaxy colors. With only two free parameters, this model is able to reproduce the observed galaxy colors as a function of redshift and stellar mass remarkably well. Our analysis suggests that the wide range of dust attenuation values measured for star-forming galaxies at a given redshift and stellar mass is almost entirely due to the effect of inclination; if all galaxies were observed edge-on, they would show very similar dust attenuation. This result has important implications for the interpretation of dust attenuation measurements, the treatment of UV and IR luminosity, and the comparison between numerical simulations and observations.