Numerical self-consistent stellar models of thin disks

Departamento de Matemática Aplicada, Instituto de Matemática, Estatística e Computação Científica, Universidade Estadual de Campinas, 13081-970 Campinas, SP, Brasil e-mail: [mujevic;letelier]@ime.unicamp.br

Received: 1 April 2005
Accepted: 13 July 2005

Abstract

We find a numerical self-consistent stellar model by finding the distribution function of a thin disk that satisfies simultaneously the Fokker-Planck and Poisson equations. The solution of the Fokker-Planck equation is found by a direct numerical solver using finite differences and a variation of Stone's method. The collision term in the Fokker-Planck equation is found using the local approximation and the Rosenbluth potentials. The resulting diffusion coefficients are explicitly evaluated using a Maxwellian distribution for the field stars. As a paradigmatic example, we apply the numerical formalism to find the distribution function of a Kuzmin-Toomre thin disk. This example is studied in some detail showing that the method applies to a large family of actual galaxies.