On the color-magnitude relation of early-type galaxies

Abstract

In this Letter, we present a study of the color-magnitude relation (CMR) of 468 early-type galaxies in the Virgo Cluster with Sloan Digital Sky Survey imaging data. The analysis of our homogeneous, model-independent data set reveals that, in all colors (u - g, g - r, g - i, i - z) similarly, giant and dwarf early-type galaxies follow a continuous CMR that is best described by an S shape. The magnitude range and quality of our data allows us to clearly confirm that the CMR in Virgo is not linear. Additionally, we analyze the scatter about the CMR and find that it increases in the intermediate-luminosity regime. Nevertheless, despite this observational distinction, we conclude from the similarly shaped CMR of semianalytic model predictions that dwarfs and giants could be of the same origin. © 2009. The American Astronomical Society. All rights reserved.