1006.1619 (P. Castelo Ferreira)

Parameterizing the flattening of galaxies rotation curves on expanding
locally anisotropic backgrounds    [PDF]

P. Castelo Ferreira

In this work are discussed possible generalizations of the expanding locally anisotropic metric ansatz with respect to approximately Newtonian many body gravitational systems. This ansatz describes local point-like matter distributions on the expanding Universe also allowing for a covariant parameterization of gravitational interactions at intermediate length scales. As an example of applicability it is modelled a disk galaxy model matching the physical parameters of the galaxy UGC2885 and it is shown that, by fine-tuning the metric functional parameter, the flattening of the galaxy rotation curve is fully parameterized by this metric. It is further analysed the mass-energy density corrections due to the expanding anisotropic background being shown that although there are negative contributions within the galaxy plane the total mass-energy density is strictly positive. Outside the galaxy plane, by considering an anisotropic functional parameter, it is shown that the mass-energy density is also strictly positive.

View original: http://arxiv.org/abs/1006.1619