The effect of dark matter and dark energy interactions on the peculiar velocity field and the kinetic Sunyaev-Zel'dovich effect

Abstract

The interaction between Dark Matter and Dark Energy has been proposedas a mechanism to alleviate the coincidence problem. We analyze itseffects on the evolution of the gravitational and the peculiar velocityfields. We find that for different model parameters peculiar velocitiesvary from a factor five times smaller to two times larger than in theΛCDM cosmological model at the same scales. We propose two newobservables sensitive to such interactions based on theireffect on the velocity field. We compare the effects onpeculiar velocities with those on the Integrated Sachs-Wolfe effectdemonstrating that velocities are more sensitive to the interaction.We show that the current upper limits on the amplitude ofthe kinetic Sunyaev-Zel'dovich power spectrum of temperatureanisotropies provide constraints on the coupling within the darksectors that are consistent with those obtained previously fromthe Cosmic Microwave Background and galaxy clusters. In particular,we show that Atacama Cosmology Telescope and South Pole Telescope datafavor the decay of Dark Energy into Dark Matter, as requiredto solve the coincidence problem.