SIMPLE 3-INTEGRAL SCALE-FREE GALAXY MODELS

Citation
Nw. Evans et al., SIMPLE 3-INTEGRAL SCALE-FREE GALAXY MODELS, Monthly Notices of the Royal Astronomical Society, 286(2), 1997, pp. 315-328
Citations number
42
Categorie Soggetti
Astronomy & Astrophysics
ISSN journal
00358711
Volume
286
Issue
2
Year of publication
1997
Pages
315 - 328
Database
ISI
SICI code
0035-8711(1997)286:2<315:S3SGM>2.0.ZU;2-2
Abstract
The Jeans equations give the second moments or stresses required to su pport a stellar population against a gravity field. A general solution of the Jeans equations for arbitrary axisymmetric scale-free densitie s in flattened scale-free potentials is given. A two-parameter subset of the solution for the second moments for the self-consistent density of the power-law models, which have exactly spheroidal equipotentials , is examined in detail, In the spherical limit, the potential of thes e models reduces to that of the singular power-law spheres. We build t he physical three-integral distribution functions that correspond to t he flattened stellar components. Next, we attack the problem of findin g distribution functions associated with the Jeans solutions in flatte ned scale-free potentials, The third or partial integral introduced by de Zeeuw, Evans & Schwarzschild for Binney's model is generalized to thin and near-thin orbits moving in arbitrary axisymmetric scale-free potentials. The partial integral is a modification of the total angula r momentum. For the self-consistent power-law models, we show how this enables the construction of simple three-integral distribution functi ons. The connection between these approximate distribution functions a nd the Jeans solutions is discussed in some detail.