English

Stellar polytropes and Navarro-Frenk-White halo models: comparison with observations

Astrophysics 2007-05-23 v2

Abstract

Motivated by the possible conflict between the Navarro-Frenk-White(NFW) model predictions for the dark matter contents of galactic systems and its correlation with baryonic surface density, we will explore an alternative paradigm for the description of dark matter halos. Such an alternative emerges from Tsallis' non-extensive thermodynamics applied to self-gravitating systems and leads to the so-called ``stellar polytrope'' (SP) model. We consider that this could be a better approach to real structures rather than the isothermal model, given the fact that the first one takes into account the non-extensivity of energy and entropy present in these type of systems characterized by long-range interactions. We compare a halo based on the Navarro-Frenk-White (NFW) and one which follows the SP description. Analyzing the dark matter contents estimated by means of global physical parameters of galactic disks, obtained from a sample of actual galaxies, with the ones of the unobserved dark matter halos, we conclude that the SP model is favored over the NFW model in such a comparison.

Keywords

Cite

@article{arxiv.astro-ph/0605665,
  title  = {Stellar polytropes and Navarro-Frenk-White halo models: comparison with observations},
  author = {Jesus Zavala and Dario Nunez and Roberto A. Sussman and Luis G. Cabral-Rosetti and Tonatiuh Matos},
  journal= {arXiv preprint arXiv:astro-ph/0605665},
  year   = {2007}
}

Comments

21 pages, 4 figures. Accepted for publication in the Journal of Cosmology and Astroparticle Physics