T. Harko, F. S. N. Lobo, M. K. Mak, S. V. Sushkov
Abstract
We consider the density profile of pressureless dark matter in Eddington-inspired Born-Infeld (EiBI) gravity. The gravitational field equations are investigated for a spherically symmetric dark matter galactic halo, by adopting a phenomenological tangential velocity profile for test particles moving in stable circular orbits around the galactic center. The density profile and the mass distribution, as well as the general form of the metric tensor is obtained by numerically integrating the gravitational field equations, and in an approximate analytical form by using the Newtonian limit of the theory. In the weak field limit, the dark matter density distribution is described by the Lane-Emden equation with polytropic index n = 1, and is nonsingular at the galactic center. The parameter kappa of the theory is determined so that the theory could provide a realistic description of the dark matter halos. The gravitational properties of the dark matter halos are also briefly discussed in the Newtonian approximation.
Keywords
Modified gravity - dark matter - galactic rotation curves
Modern Physics Letters A
Volume 29, Number 09, Page 1450049_1
2014 March
