VELOCITY PROFILES OF OSIPKOV-MERRITT MODELS

A simple algorithm is presented for the calculation of the projected l ine-of-sight velocity profiles (VPs) of non-rotating anisotropic spher ical dynamical models with a phase-space distribution function of the Osipkov-Merritt type. The velocity distribution in these models is iso tropic inside the anisotropy radius r(a) and becomes increasingly radi ally biased at larger radii. VP shape parameters are presented for a f amily of models in which the luminous mass density has a power-law cus p rho(L) proportional to r(-gamma) at small radii and a power-law fall -off rho(L) proportional to r(-4) at large radii. Self-consistent mode ls and models in which the luminous matter is embedded in a dark halo are discussed. The effects of changes in the cusp slope gamma and in t he anisotropy radius r(a) are documented, and the area in the (gamma, r(a))-plane that contains physical models is delineated. The shapes of the VPs of the models show a considerable (and observable) variation with projected galactocentric radius. These models will be useful for interpreting the data on the VP shapes of elliptical galaxies that are now becoming available.