Publication date: Jul 2018
Abstract:
We discuss in the framework of general relativity the role of the dark
energy represented by the cosmological constant, restricted due to
cosmological tests, in the polytropic models of dark matter halos. The
internal spacetime of the polytropic spheres governs circular geodesic
orbits that can be compared with the velocity curves observed in large
galaxies, indicating the possibility to use for the halo model both non-
relativistic very extended and diluted polytropes, or relativistic
polytropes with nearly critical value of the relativistic parameter
sigma = p_mathrm{c}/varrho_mathrm{c} enabling extremely large polytrope
extension, limited efficiently by the influence of the dark energy to
agree with extension of dark matter halos of large galaxies. We also
show that the so-called trapping relativistic polytropes with extremely
large extension allow for gravitational instability of their central
parts leading to the creation of a supermassive black hole inside of
such an extremely extended polytrope representing galactic halo.
Authors:
Stuchlik, Zdenek; Novotn, Jan; Hladík, Jan;