Cosmological evolution in bimetric gravity: observational constraints and LSS signatures

Abstract

AbstractBimetric gravity is an interesting alternative to standard GR given its potential to provide a concrete theoretical framework for a ghost-free massive gravity theory. Here we investigate a class of Bimetric gravity models for their cosmological implications. We study the background expansion as well as the growth of matter perturbations at linear and second order. We use low-redshift observations from SnIa (Pantheon+ and SH0ES), Baryon Acoustic Oscillations (BAO), the growth ($$f\sigma _{8}$$fσ8) measurements and the measurement from Megamaser Cosmology Project to constrain the Bimetric model. We find that the Bimetric models are consistent with the present data alongside the$$\Lambda $$ΛCDM model. We reconstructed the “ effective dark energy equation of state”($$\omega _{de}$$ωde) and “Skewness”($$S_{3}$$S3) parameters for the Bimetric model from the observational constraints and show that the current low-redshift data allow significant deviations in$$\omega _{de}$$ωdeand$$S_{3}$$S3parameters with respect to the$$\Lambda $$ΛCDM behaviour. We also look at the ISW effect via galaxy-temperature correlations and find that the best fit Bimetric model behaves similarly to$$\Lambda $$ΛCDM in this regard.