Constraints on interacting dark energy revisited: implications for the Hubble tension

Abstract: In this paper, we have revisited a class of coupled dark energy models where dark energy interacts with dark matter via phenomenological interactions. We included correction terms on the perturbation equations taking into account the perturbation of the Hubble rate, which was absent in previous works. We also consider more recent data sets such as cosmic microwave background (CMB) anisotropies from \textit{Planck} 2018, type I-a supernovae (SNIa) measurements from Pantheon+ and data from baryon acoustic oscillations (BAO), and redshift space distortions (RSD). One of the models presents a strong incompatibility when different cosmological datasets are used. We analyzed the influence of the SH0ES Cepheid host distances on the results and, although for one model the discrepancy of $H_0$ is reduced to $1.3\sigma$ when compared to $\Lambda$CDM and $4.6\sigma$ when compared to the SH0ES team, joint analysis is incompatible. Including BAO with RSD shows incompatibility with SH0ES for all models considered here. We performed a model comparison, but there is no clear preference for interacting dark energy over $\Lambda$CDM ($|\Delta \chi^2|<1$ for all the models for joint analysis CMB+BAO+RSD+SNIa). We conclude that the models of interactions in the dark sector considered in this paper are not flexible enough to fit all the cosmological data including values of $H_0$ from SH0ES in a statistically acceptable way, either the models would need to be modified to include further flexibility of predictions or that there remains a tension in this coupled dark energy paradigm.