HOMOGENEOUS VELOCITY-DISTANCE DATA FOR PECULIAR VELOCITY ANALYSIS .3.THE MARK-III CATALOG OF GALAXY PECULIAR VELOCITIES

This is the third in a series of papers in which we assemble and analy ze a homogeneous catalog of peculiar velocity data. In Papers I and II , we described the Tully-Fisher (TF) redshift-distance samples that co nstitute the bulk of the catalog and our methodology for obtaining mut ually consistent TF calibrations for these samples. In this paper, we supply further technical details of the treatment of the data and pres ent a subset of the catalog in tabular form. The full catalog, known a s the Mark III Catalog of Galaxy Peculiar Velocities, is available in accessible on-line databases, as described herein. The electronic cata log incorporates not only the TF samples discussed in Papers I and II but also elliptical galaxy D-n-sigma samples originally presented else where. The relative zero pointing of the elliptical and spiral data se ts is discussed here. The basic elements of the Mark III Catalog are t he observables for each object (redshift, magnitude, velocity width, e tc.) and inferred distances derived from the TF or D-n-sigma relations . Distances obtained from both the forward and inverse TF relations ar e tabulated for the spirals. Malmquist bias-corrected distances are co mputed for each catalog object using density fields obtained from the IRAS 1.2 Jy redshift survey. Distances for both individual objects and groups are provided. A variety of auxiliary data, including distances and local densities predicted from the IRAS redshift survey reconstru ction method, are tabulated as well. We study the distributions of TF residuals for three of our samples and conclude that they are well app roximated as Gaussian. However, for the Mathewson et al. sample we dem onstrate a significant decrease in TF scatter with increasing velocity width. We test for, but find no evidence of, a correlation between TF residuals and galaxy morphology. Finally, we derive transformations t hat map the apparent magnitude and velocity width data for each spiral sample onto a common system. This permits the application of analysis methods that assume that a unique TF relation describes the entire sa mple.