S0 galaxies in Fornax: data and kinematics

Abstract

We have obtained long-slit spectroscopy for a sample of 9 S0 galaxies in the Fornax Cluster using the FORS2 spectrograph at the 8.2m ESO VLT. From these data, we have extracted the kinematic parameters, comprising the mean velocity, velocity dispersion and higher-moment H3 and H4 coefficients, as a function of position along the major axes of these galaxies. Comparison with published kinematics indicates that earlier data are often limited by their lower signal-to-noise ratio and relatively poor spectral resolution. The greater depth and higher dispersion of the new data mean that we reach well beyond the bulges of these systems, probing their disk kinematics in some detail for the first time. Qualitative inspection of the results for individual galaxies shows that they are not entirely simple systems, perhaps indicating a turbulent past. Nonetheless, we are able to derive reliable circular velocities for most of these systems, which points the way toward a study of their Tully-Fisher relation. This study, along with an analysis of the stellar populations of these systems out to large galactocentric distances, will form the bases of future papers exploiting these new high-quality data, hopefully shedding new light on the evolutionary history of these systems.