Analytical Dynamical Models for Double-Power-Law Galactic Nuclei

Abstract

Motivated by the finding that the observed surface brightness profile of many galactic nuclei are well fit by double-power-laws, we explore a range of spherical self-consistent dynamical models with this light profile. We find that the corresponding deprojected volume density profile, phase space density and line-of-sight velocity distribution of these models are well fit by simple analytic approximations. We illustrate the application of these models by fitting a sample of about 25 galactic nuclei observed by Hubble Space Telescope. We give the derived volume density, phase space density, velocity dispersion and line profile parameters in tables. The models are useful for predicting kinematic properties of these galaxies for comparison with future observations. They can also be easily applied to seed N-body simulations of galactic nuclei with realistic density profiles for studying the evolution of these systems.