Hubble Space Telescope photometry of the central regions of Virgo Cluster elliptical galaxies. 1: Observations, discussion, and conclusions

Using the Hubble Space Telescope we have observed at 10 pc resolution the nuclei of a luminosity-limited sample of 14 E and E/SO galaxies in the Virgo Cluster with magnitudes B(sub T) = 9.4 to 13.4. In this paper we present the images, and discuss the results of the detailed analysis of the surface photometry given in two companion papers. We find that the nuclear and near-nuclear morphologies confirm and strengthen the previously recognized dichotomy of 'E' galaxies into 'true' and 'disky' subtypes. The latter, usually classified E4 or later, often show a bright nuclear disk of radius approximately 100 pc. Essentially all early-type galaxies with -18 greater than M(sub B) greater than -20 are disky. Most true E galaxies are classified E4 or earlier. Most galaxies of both types show dust in the nuclear regions, the most remarkable example being a compact dust disk in NGC 4261. Other than dust, no anomalies were detected in the centers of the three galaxies in our sample which show clear kinematic evidence for a decoupled component.