Dark sector interactions in light of weak lensing data

Abstract: The current observational tensions in the standard cosmological model have reinforced the research on dynamical dark energy, in particular on models with non-gravitational interaction between the dark components. Analyses of late-time observables like type Ia supernovas (SNe Ia) and large-scale structures (LSS) are not conclusive about the presence of energy flux between dark energy and dark matter, while the anisotropy spectrum of the cosmic microwave background (CMB) is fully consistent with no interaction at all. As background and visible matter tests are less sensitive to the suppression/enhancement in the dark matter power spectrum, which is a characteristic of interacting models, while the CMB spectrum is strongly affected by it, this could be the origin of those results. In order to confirm it and at the same time to rule out the role of possible systematics between early and late-time observations, the use of a low redshift observable sensitive to the gravitational potential generated by dark matter is crucial. In the present paper, we investigate the observational viability of a class of interacting dark energy models, namely with energy exchange between vacuum-type and dust components, in the light of the Dark Energy Survey (DES) observations of galaxy weak lensing, in the context of a spatially-flat Friedmann-Lema^itre-Robertson-Walker spacetime. The best fit of our analysis is entirely consistent with null interaction, confirming the CMB based constraints.