The structure of elliptical galaxies in the Virgo cluster. Results from the INT Wide Field Survey^*

¹ Universitá degli Studi di Milano-Bicocca, P.zza della Scienza 3, 20126 Milano, Italy e-mail: [Giuseppe.Gavazzi;alessandro.donati]@mib.infn.it
² Department of Physics and Astronomy, Cardiff University, UK e-mail: sabina.sabatini@astro.cf.ac.uk
³ Laboratoire d'Astrophysique de Marseille, BP8, Traverse du Siphon, 13376 Marseille, France e-mail: alessandro.boselli@oamp.fr
⁴ Max-Planck-Institut für Astrophysik, Garching, Germany e-mail: zibetti@mpa-garching.mpg.de

Received: 24 October 2003
Accepted: 16 September 2004

Abstract

We report on a complete CCD imaging survey of 226 elliptical galaxies in the North-East quadrant of the Virgo cluster, representative of the properties of giant and dwarf elliptical galaxies in this cluster. We fit their radial light profiles with the Sersic model of light distribution. We confirm the result of Graham & Guzman ([CITE], AJ, 125, 2936) that the apparent dichotomy between E and dE galaxies in the luminosity– plane no longer appears when other structural parameters are considered and can be entirely attributed to the onset of “core” galaxies at  mag. When “core” galaxies are not considered, E and dE form a unique family with n linearly increasing with the luminosity. For 90 galaxies we analyze the  color indices, both in the nuclear and in the outer regions. Both indices are bluer toward fainter luminosities. We find also that the outer color gradients do not show any significant correlation with the luminosity. The scatter in all color indicators increases significantly toward lower luminosities, e.g. galaxies fainter than have a  spread > 0.5 mag.