Spatially resolved spectroscopy of Coma cluster early–type galaxies

Abstract

We present long slit spectra for a magnitude limited sample of 35 E and S0 galaxies of the Coma cluster. The high quality of the data allowed us to derive spatially resolved spectra for a substantial sample of Coma galaxies for the first time. From these spectra we obtained rotation curves, the velocity dispersion profiles and the H 3 and H 4 coefficients of the Hermite decomposition of the line of sight velocity distribution. Moreover, we derive the radial line index profiles of Mg, Fe and H line indices out to with high signal-to-noise ratio. We describe the galaxy sample, the observations and data reduction, and present the spectroscopic database. Ground-based photometry for a subsample of 8 galaxies is also presented. The Coma cluster is one of the richest known clusters of galaxies, spanning about 4 decades in density. Hence it is the ideal place to study the structure of galaxies as a function of environmental density in order to constrain the theories of galaxy formation and evolution. Based on the spectroscopic database presented, we will discuss these issues in a series of future papers.