Optical morphology evolution of infrared luminous galaxies in goods-N

We combine optical morphologies and photometry from HST, redshifts from Keck, and mid-infrared luminosities from Spitzer for an optically selected sample of similar to 800 galaxies in GOODS-N to track the morphology evolution of luminous infrared galaxies (LIRGs) since redshift z =1. We find a 50% decline in the number of LIRGs from z similar to 1 to lower redshift, in agreement with previous studies. In addition, there is evidence for a morphological evolution of the populations of LIRGs. Above z = 0.5, roughly half of all LIRGs are spiral, the peculiar/irregular-to-spiral ratio is ratio is similar to 0.7, and both classes span a similar range of and. At low z, spirals account for one-third of LIRGs, the peculiar-to-spiral fraction rises to 1.3, and for a given spirals tend to have lower IR luminosity M-B than peculiars. Only a few percent of LIRGs at any redshift are red early-type galaxies. For blue galaxies (U - B < 0.2), M-B is well correlated with L-IR with an rms scatter (about a bivariate linear fit) of similar to 0.25 dex in IR luminosity. Among blue galaxies that are brighter than M-B = -21, 75% are LIRGs, regardless of regardless of redshift. These results can be explained by a scenario in which at high z, most large spirals experience an elevated star formation rate as LIRGs. Gas consumption results in a decline of LIRGs, especially in spirals, to lower redshifts.