Journal Article

Sérsic Galaxy with Sérsic Halo Models of Early-type Galaxies: A Tool for N N -body Simulations

Coppola, G., Capaccioli, M., La Barbera, F.

2009

Overview

We present spherical, nonrotating, isotropic models of early-type galaxies with stellar and dark-matter components both described by deprojected Sérsic density profiles and prove that they represent physically admissible stable systems. Using empirical correlations and recent results of N N -body simulations, all the free parameters of the models are expressed as functions of one single quantity: the total ( B B -band) luminosity of the stellar component. We analyze how to perform discrete N N -body realizations of Sérsic models. To this end, an optimal smoothing length is derived, defined as the softening parameter minimizing the error on the gravitational potential for the deprojected Sérsic model. It is shown to depend on the Sérsic index n n and on the number of particles of the N N -body realization. A software code allowing the computations of the relevant quantities of one- and two-component Sérsic models is provided. Both the code and the results of the present work are primarily intended as tools to perform N N -body simulations of early-type galaxies, where the structural nonhomology of these systems (i.e., the variation of the shape parameter along the galaxy sequence) might be taken into account.

• Publisher: University of Chicago Press
• Subject: Average linear density / Distribution functions / Galactic radii / Galaxies / Gravitational fields / Luminosity / Modeling / Parametric models / Stellar masses / Stellar radii