Detectability of torsion gravity via galaxy clustering and cosmic shear measurements
Abstract
Alterations of the gravity Lagrangian introduced in modified torsion gravity theories—also referred to as f(T) gravity—allows for an accelerated expansion in a matterdominated Universe. In this framework, the cosmic speedup is driven by an effective "torsion fluid." Besides the background evolution of the Universe, structure formation is also modified because of a timedependent effective gravitational constant. Here, we investigate the imprints of f(T) gravity on galaxy clustering and weak gravitational lensing to the aim of understanding whether future galaxy surveys could constrain torsion gravity and discriminate between it and standard general relativity. Specifically, we compute Fisher matrix forecasts for two viable f(T) models to both infer the accuracy on the measurement of the model parameters and evaluate the power that a combined clustering and shear analysis will have as a tool for model selection. We find that with such a combination of probes it will indeed be possible to tightly constrain f(T) model parameters. Moreover, the Occam's razor provided by the Bayes factor will allow us to confirm an f(T) powerlaw extension of the concordance ΛCDM model, if a value larger than 0.02 of its powerlaw slope were measured, whereas in ΛCDM it is exactly 0.
 Publication:

Physical Review D
 Pub Date:
 April 2014
 DOI:
 10.1103/PhysRevD.89.083520
 arXiv:
 arXiv:1311.1004
 Bibcode:
 2014PhRvD..89h3520C
 Keywords:

 98.80.k;
 95.36.+x;
 98.80.Es;
 Cosmology;
 Dark energy;
 Observational cosmology;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 General Relativity and Quantum Cosmology
 EPrint:
 14 pages, 4 figures, 4 tables