Radial velocities and central velocity dispersions are derived for 238 E/S0 galaxies from medium-resolution spectroscopy .
New spectroscopic data have been obtained as part of a study of the Fundamental Plane distances and peculiar motions of early-type galaxies in three selected directions of the South Equatorial Strip , undertaken in order to investigate the reality of large-scale streaming motion ; results of this study have been reported in Müller et al . ( 1998 ) .
The new APM South Equatorial Strip Catalog ( -17 ^ { \circ } .5 < \delta < +2 ^ { \circ } .5 ) was used to select the sample of field galaxies in three directions : ( 1 ) 15h10 – 16h10 ; ( 2 ) 20h30 – 21h50 ; ( 3 ) 00h10 – 01h30 .
The spectra obtained have a median S / N per Å of 23 , an instrumental resolution ( FWHM ) of \sim 4 Å , and the spectrograph resolution ( dispersion ) is \sim 100 km s ^ { -1 } .
The Fourier cross-correlation method was used to derive the radial velocities and velocity dispersions .
The velocity dispersions have been corrected for the size of the aperture and for the galaxy effective radius .
Comparisons of the derived radial velocities with data from the literature show that our values are accurate to 40 km s ^ { -1 } .
A comparison with results from J \o rgensen et al . ( 1995 ) shows that the derived central velocity dispersion have an rms scatter of 0.036 in \log \sigma .
There is no offset relative to the velocity dispersions of Davies et al . ( 1987 ) .