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Authors:
G. Gavazzi, A. Donati, O. Cucciati, S. Sabatini, A. Boselli, J. Davies, S. Zibetti
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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 r^(1/n) model of light distribution. We confirm the
result of Graham & Guzman (2003) that the apparent dichotomy between E and dE
galaxies in the luminosity - mu e plane no longer appears when other
structural parameters are considered and can be entirely attributed to the
onset of "core" galaxies at B_T sim -20.5 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 B-I 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 B_T sim -15 have a B-I spread 0.5 mag.
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