Cosmological constraints on $$\Lambda (t)$$CDM models

Abstract

AbstractProblems with the concordance cosmology $$\Lambda $$ Λ CDM as the cosmological constant problem, coincidence problems and Hubble tension has led to many proposed alternatives, as the $$\Lambda (t)$$ Λ ( t ) CDM, where the now called $$\Lambda $$ Λ cosmological term is allowed to vary due to an interaction with pressureless matter. Here, we analyze one class of these proposals, namely, $$\Lambda =\alpha 'a^{-2}+\beta H^2+\lambda _*$$ Λ = α ′ a - 2 + β H 2 + λ ∗ , based on dimensional arguments. Using SNe Ia, cosmic chronometers data plus constraints on $$H_0$$ H 0 from SH0ES and Planck satellite, we constrain the free parameters of this class of models. By using the Planck prior over $$H_0$$ H 0 , we conclude that the $$\lambda _*$$ λ ∗ term can not be discarded by this analysis, thereby disfavouring models only with the time-variable terms. The SH0ES prior over $$H_0$$ H 0 has an weak evidence in this direction. The subclasses of models with $$\alpha '=0$$ α ′ = 0 and with $$\beta =0$$ β = 0 can not be discarded by this analysis. Finally, by using distance priors from CMB, the $$\Lambda $$ Λ time-dependence was quite restricted.