Testing models of vacuum energy interacting with cold dark matter

Abstract

We test the models of vacuum energy interacting with cold dark matter and try to probe the possible deviation from the $Λ$CDM model using current observations. We focus on two specific models, $Q=3βHρ_Λ$ and $Q=3βHρ_c$. The data combinations come from the Planck 2013 data, the baryon acoustic oscillations measurements, the type-Ia supernovae data, the Hubble constant measurement, the redshift space distortions data and the galaxy weak lensing data. For the $Q=3βHρ_c$ model, we find that it can be tightly constrained by all the data combinations, while for the $Q=3βHρ_Λ$ model, there still exist significant degeneracies between parameters. The tightest constraints for the coupling constant are $β=-0.026^{+0.036}_{-0.053}$ (for $Q=3βHρ_Λ$) and $β=-0.00045\pm0.00069$ (for $Q=3βHρ_c$) at the $1σ$ level. For all the fit results, we find that the null interaction $β=0$ is always consistent with data. Our work completes the discussion on the interacting dark energy model in the recent Planck 2015 papers. Considering this work together with the Planck 2015 results, it is believed that there is no evidence for the models beyond the standard $Λ$CDM model from the point of view of possible interaction.