Cosmic Dragons: Galactic evolution in the COSMOS field

I introduce Red Dragon: a tool for characterizing galaxy populations in multi-color photometric space, using evolving error-corrected Gaussian mixture models. This algorithm models the red sequence (RS) and the blue cloud (BC), distinguishing quiescent galaxies from star-forming galaxies with high accuracy out to redshift z~3 in the COSMOS field. Parameterizing galaxy populations in this manner lends itself to rest frame spectral analysis of colors, color scatter, and inter-color correlations. Color scatter tends to decrease toward longer wavelengths; the RS shows decreased scatter towards higher masses whereas the BC shows relatively constant scatter as a function of galactic stellar mass. We further characterize specific star formation rates and galactic age for both populations as functions of mass and redshift. Red Dragon modeling of RS and BC improves our understanding of both populations and opens the door to more precise galaxy population characterization in future deep optical/IR systems.