Quantitative morphology and color gradients of E+A galaxies in distant galaxy clusters

Abstract

Narrow band multifilter photometry of the galaxy populations of four galaxy clusters at z=0.4-0.5 has provided us with a sample of 73 E+A galaxies which are secure cluster members. For 34 of them HST images are available (WFPC2). We have determined surface brigthness profiles and by means of an exponential or r^1/4 law fit we have classified the galaxies on the basis of their bulge to disk ratio. We have found that most of these galaxies are disk systems judging from the exponential nature of their profiles. We have also derived color gradients for 10 E+A galaxies in Cl0016+16 to study the spatial distribution of the starburst and to distinguish among the physical mechanisms at its origin. Color gradients indicate that most of the E+A galaxies in Cl0016+16 show little spatial variation in V-I colors (restframe U-V). Thus, our large and homogeneous sample of distant E+A galaxies confirms the claim that their enhanced star formation is a galaxy-wide phenomenon.