| Abstract | Twenty-one centimeter hydrogen line velocities, half-widths, and fluxes are presented for 112 spiral and irregular galaxies, the majority in groups. Comparison of the velocities with values listed in the de Vaucouleurs (1976) Second Reference Catalog (RC2) suggests that the mean errors of RC2 velocities may be underestimated typically by a factor of 1.5. Integrated Brandt (1960) masses are derived from the half-widths, taking into account the increased knowledge of the properties of galactic rotation curves obtained by Huchtmeier (1975). Masses derived by the present technique are, on the average, within a factor of 1.4 of those determined by detailed analysis of individual rotation curves. Holmberg luminosities corrected for internal and Galactic extinction are determined. The sample of galaxies has an average integrated mass-to-light ratio of 11 + or - 1 solar units (when H = 50 km/s per Mpc), and the average integrated mass-to-light ratio is independent of morphological type. The mass-to-light ratio of the region within a Holmberg radius, however, tends to decrease toward later Hubble types. |
