Strong lensing constraints on bimetric massive gravity

TL;DR

This paper investigates how bimetric massive gravity affects gravitational lensing and galaxy dynamics, constraining the theory's parameters based on observations of elliptical galaxies and their consistency with general relativity.

Contribution

It derives lensing and dynamical properties in Hassan-Rosen bimetric gravity and constrains the theory's parameters using galaxy observations, showing consistency with general relativity for most parameter ranges.

Findings

Constraints on the effective length-scale of the theory from galaxy observations.

Most parameter values are consistent with observed galaxy lensing and dynamics.

Background solutions resembling the standard cosmological model are achievable without fine-tuning.

Abstract

We derive dynamical and gravitational lensing properties of local sources in the Hassan-Rosen bimetric gravity theory. Observations of elliptical galaxies rule out values of the effective length-scale of the theory, in units of the Hubble radius, in the interval 10^-6 < lambda_g/r_H < 10^-3, unless the proportionality constant between the metrics at the background level is far from unity, in which case general relativity is effectively restored for local sources. In order to have background solutions resembling the concordance cosmological model, without fine-tuning of the parameters of the model, we are restricted to the upper interval, or lambda_g/r_H ~ 1. Except for a limited range of parameter values, the Hassan-Rosen theory is thus consistent with the observed lensing and dynamical properties of elliptical galaxies.