Cosmography of f(R) - brane cosmology

TL;DR

This paper uses cosmography to analyze f(R) brane-world models, demonstrating their consistency with LCDM at low redshift and constraining model parameters using supernova and BAO data.

Contribution

It applies cosmography to f(R) brane-world models, providing observational constraints and showing their viability compared to standard cosmology.

Findings

Model is consistent with LCDM at low redshift

Constraints on f(R) and its derivatives from supernova and BAO data

Model self-accelerates without dark energy

Abstract

Cosmography is a useful tool to constrain cosmological models, in particular dark energy models. In the case of modified theories of gravity, where the equations of motion are generally quite complicated, cosmography can contribute to select realistic models without imposing arbitrary choices a priori. Indeed, its reliability is based on the assumptions that the universe is homogeneous and isotropic on large scale and luminosity distance can be "tracked" by the derivative series of the scale factor a(t). We apply this approach to induced gravity brane-world models where an f(R)-term is present in the brane effective action. The virtue of the model is to self-accelerate the normal and healthy DGP branch once the f(R)-term deviates from the Hilbert-Einstein action. We show that the model, coming from a fundamental theory, is consistent with the LCDM scenario at low redshift. We finally estimate the cosmographic parameters fitting the Union2 Type Ia Supernovae (SNeIa) dataset and the distance priors from Baryon Acoustic Oscillations (BAO) and then provide constraints on the present day values of f(R) and its second and third derivatives.