Rotational properties of 23Sb galaxies.

Major-axis spectra and rotation-curve data are presented for 23 Sb galaxies, most of them field galaxies of high inclination. Relations between the integral properties of mass, luminosity, radius, and rotational velocity are derived and are compared with similarly derived relations for an analogous set of 20 Sc galaxies. It is shown that: (1) the rotational velocities remain high at large nuclear distances for all 23 Sb galaxies; (2) rotational properties are a function of luminosity within the Sb class; (3) many Sb rotation curves share the characteristic form seen in the Sc galaxies; (4) isophotal radius and blue luminosity are tightly correlated; (5) the conventional Tully-Fisher relations hold for the Sb's but the regression line for the Sb's is displaced about 0.1 dex from that for Sc's; (6) the mass of an Sb is higher by 0.2 dex than that of an Sc of equivalent luminosity; and (7) the mass/blue luminosity relation is independent of luminosity within a single Hubble class.