Velocities and Photometry for E and S0 galaxies

Measurements of central velocity dispersion (sigma), total B magnitudes (B_T), the photometric parameter D_n, and the absorption-line index Mgi_2 are presented. Both internal and external comparisons indicate that measurements of log{sigma} are accurate to 0.05 dex, B_T to 0.15 mag, D_n to 0.015 dex, and Mg_2 to 0.017 mag.

These data have been used in a previous paper by Dressler and Faber to estimate distances for these galaxies via the D_n - {sigma} relation. It is shown in this paper that the D_n - Mg_2 relation also predicts the same trends of peculiar velocity with distance, but with less accuracy. The relative accuracy of other distance indicators for elliptical galaxies is also discussed.