Color Profiles of Disk Galaxies since z~1: Probing Outer Disk Formation Scenarios

TL;DR

This study analyzes deep color profiles of 415 disk galaxies from z~1 to present, revealing persistent color minima at disk truncations consistent with models of star formation cut-offs and stellar redistribution.

Contribution

It provides the first extensive observational evidence linking color profile features at disk breaks to secular evolutionary processes in galaxies.

Findings

Color minima at disk truncations are consistent across redshifts.

Color profile features support models of star formation cut-offs.

Secular processes influence outer disk formation over 8 Gyr.

Abstract

We present deep color profiles for a sample of 415 disk galaxies within the redshift range 0.1<z<=1.1, and contained in HST-ACS imaging of the GOODS-South field (Giavalisco et al. 2004). For each galaxy, passband combinations are chosen to obtain, at each redshift, the best possible aproximation to the rest-frame u-g color. We find that objects which show a truncation in their stellar disk (Type II objects) usually show a minimum in their color profile at the break, or very near to it, with a maximum to minimum amplitude in color of <~0.2 mag/arcsec^2, a feature which is persistent through the explored range of redshifts (i.e. in the last ~8 Gyr). This color structure is in qualitative agreement with recent model expectations (Roskar et al. 2008) where the break of the surface brightness profiles is the result of the interplay between a radial star formation cut-off and a redistribution of stellar mass by secular processes.