Velocity profiles of Osipkov-Merritt models
Abstract
A simple algorithm is presented for the calculation of the projected line-of-sight velocity profiles (VPs) of non-rotating anisotropic spherical dynamical models with a phase-space distribution function of the Osipkov-Merritt type. The velocity distribution in these models is isotropic inside the anisotropy radius r_a_ and becomes increasingly radially biased at larger radii. VP shape parameters are presented for a family of models in which the luminous mass density has a power-law cusp ρL is proportional to rgamma^ at small radii and a power-law fall- off ρL is proportional to r^-4^ at large radii. Self-consistent models and models in which the luminous matter is embedded in a dark halo are discussed. The effects of changes in the cusp slope γ and in the anisotropy radius r_a_ are documented, and the area in the (γ, 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.
- Publication:
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Monthly Notices of the Royal Astronomical Society
- Pub Date:
- October 1995
- DOI:
- 10.1093/mnras/276.4.1131
- arXiv:
- arXiv:astro-ph/9501054
- Bibcode:
- 1995MNRAS.276.1131C
- Keywords:
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- Astrophysics
- E-Print:
- 10 pages, uuencoded compressed PostScript, includes 7 figures