Faint tidal features in galaxies within the Canada-France-Hawaii telescope legacy survey wide fields

Abstract

We present an analysis of the detectability of faint tidal features in galaxies from the wide-field component of the CanadaFranceHawaii Telescope Legacy Survey. Our sample consists of 1781 luminous (Mr < ?19.3 mag) galaxies in the magnitude range 15.5 mag < r < 17 mag and in the redshift range 0.04 < z < 0.2. Although we have classified tidal features according to their morphology (e.g., streams, shells, and tails), we do not attempt to interpret them in terms of their physical origin (e.g., major versus minor merger debris). Instead, we provide a catalog that is intended to provide raw material for future investigations which will probe the nature of low surface brightness substructure around galaxies. We find that around 12% of the galaxies in our sample show clear tidal features at the highest confidence level. This fraction rises to about 18% if we include systems with convincing, albeit weaker tidal features, and to 26% if we include systems with more marginal features that may or may not be tidal in origin. These proportions are a strong function of rest-frame color and of stellar mass. Linear features, shells, and fans are much more likely to occur in massive galaxies with stellar masses >1010.5M⊙, and red galaxies are twice as likely to show tidal features than are blue galaxies. © 2013. The American Astronomical Society. All rights reserved.