Revisiting the color-magnitude relation of the Virgo cluster

GONZÁLEZ, N.; SMITH CASTELLI, A. V.; FAIFER, F.; FORTE, J. C.

Buenos Aires

Workshop; Second Workshop on Numerical and Observational Astrophysics: "From the First Structures to the Universe Today"; 2011

Instituto de Astronomia y Fisica del Espacio (UBA-CONICET)

The colour-magnitude relation (CMR) of early-type galaxies is a well   studied photometric relation. In the colour-magnitude diagram,   elliptical and lenticular galaxies define a sequence in the sense that   the more massive systems are redder than the fainter ones. Spectroscopic   studies of giant and dwarf ellipticals have shown that this relation   would be mainly driven by metallicity and star formation effects. It   is widely accepted that the CMR in groups and clusters of galaxies is   linear along its extension, and that it shows no perceptible change of   slope from the bright galaxies to the dwarf regime, except, perhaps, at   the very bright end. In addition, there is strong evidence for the   universality of this relation in clusters of galaxies. However,   non-linear trends for the CMR of the Virgo cluster have been reported by   Ferrarese et al. (2006, ApJS, 164, 334) and Janz & Lisker (2009,   ApJ, 696, L102), in contrast to the results found in more distant   associations. In this contribution, and as part of the degree   thesis of Nélida González, we revisit the CMR of the Virgo cluster   through the publicly available data of the "Virgo Advanced Camera   Survey". We explore if the non-linearity found for this cluster may be   related with a morphological misclassification of some galaxies of the   sample.