Friday, August 31, 2012

1208.6241 (S. Mendoza et al.)

Gravitational lensing with $ f(χ)=χ^{3/2} $ gravity in accordance
with astrophysical observations
   [PDF]

S. Mendoza, T. Bernal, X. Hernandez, J. C. Hidalgo, L. A. Torres
In this article we perform a second order perturbation analysis of the gravitational metric theory of gravity $ f(\chi) = \chi^{3/2} $ developed by Bernal et al. (2011). We show that the theory is capable to account exactly for two observational facts: (1) the phenomenology of flattened rotation curves through the Tully-Fisher relation observed in spiral galaxies, and (2) the details of observations of gravitational lensing in galaxies and groups of galaxies, without the need of any dark matter. We show how all dynamical observations on flat rotation curves and gravitational lensing can be synthesised in terms of the empirically required metric coefficients of any metric theory of gravity. We construct the corresponding metric components for the theory presented at second order in perturbation, which are shown to be perfectly compatible with the empirically derived ones. It is also shown that, in order to obtain a complete full agreement with the observational results, a specific signature of Riemann's tensor has to be chosen. This signature corresponds to the one most widely used nowadays in relativity theory. Also, a computational program, the MEXICAS (Metric EXtended-gravity Incorporated through a Computer Algebraic System) code, developed for its usage in the Computer Algebraic System (CAS) Maxima for working out perturbations on a metric theory of gravity is presented and made publicly available.
View original: http://arxiv.org/abs/1208.6241

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