8 Summary

We have obtained new radial velocities and central velocity dispersions for 179 E and S0 galaxies in three selected directions in the APM South Equatorial Strip, as well as for 40 galaxies in the Coma cluster. Observations were made with the 2.4 m and 1.3 m telescopes of the MDM Observatory on Kitt Peak, Arizona, using the Mark III spectrograph, and at the 4.4 m MMT, using the Red Channel. The spectra have a mean S/N per $\mbox{\AA}$ of 23.

Radial velocities and central velocity dispersions have been determined by the Fourier cross-correlation method. The velocity dispersions have been corrected for the effect of the aperture size and for the galaxy's effective radius. We find that the typical uncertainties on the derived parameters are $\pm$ 40 km s^-1 in cz and $\pm$ 0.045 in $\log \sigma$. In comparisons with literature data, no offsets or systematic differences are seen. The accuracy of 8 - 10% in the derived velocity dispersions is high enough for the values to be used in the application of Fundamental Plane analysis. The results given here have been used together with photometric data (Müller et al. 2000) to derive Fundamental Plane distances to the sample galaxies in order to determine their peculiar velocities and thereby investigate the reality of large-scale streaming motion; results have been reported in Müller et al. (1998).

Acknowledgements

GW wishes to acknowledge partial support from the Alexander von Humboldt Foundation during a visit to the Ruhr-Universität Bochum, and also from NSF grant AST93-47714. KM acknowledges financial support from a Dartmouth Fellowship and from a Research Studentship at the European Southern Observatory in Munich.