Low redshift constraints on scalecovariant models
Abstract
The search for a physical model which explains the observed recent acceleration of the universe is a compelling task of modern fundamental cosmology. Recently Fernandes et al. presented low redshift observational constraints on a scale invariant model by Maeder. Phenomenologically this can be interpreted as a bimetric theory with a timedependent cosmological constant. It was shown that a matter density Ω_{m} ∼ 0 . 3 is a poor fit to the data, and the bestfit model would require a fluid with a much smaller density and a significantly positive equation of state parameter. This model is a particular case of an earlier and broader class of models by Canuto et al., which we study here. Specifically, we consider it in two distinct scenarios: as a genuine alternative to ΛCDM (i.e., without any cosmological constant) and as a parametric extension thereof (where both a cosmological constant and the new mechanism can coexist, and the relative contributions of both are determined by the data). We find that the first scenario can in principle fit the lowredshift data (but a good fit would require values of model parameters, such as the matter equation of state, in conflict with other data), while in the second one the deviation from ΛCDM is constrained to be small.
 Publication:

Physics of the Dark Universe
 Pub Date:
 March 2022
 DOI:
 10.1016/j.dark.2022.100964
 arXiv:
 arXiv:2201.12863
 Bibcode:
 2022PDU....3500964M
 Keywords:

 Cosmology;
 Dark energy;
 Modified gravity;
 Cosmological observations;
 Statistical analysis;
 Astrophysics  Cosmology and Nongalactic Astrophysics;
 General Relativity and Quantum Cosmology;
 High Energy Physics  Phenomenology
 EPrint:
 13 page, 4 figures