http://arxiv.org/abs/1706.04953
We study large-scale inhomogeneous perturbations and instabilities of interacting dark energy models. Past analysis of large-scale perturbative instabilities, has shown that we can only test interacting dark-energy models with observational data when its parameter ranges are either $w_{x}\geq -1~$and$~\xi \geq 0,$ or $w_{x}\leq -1~$ and $~\xi \leq 0$, where $w_{x}$ is the dark energy equation of state, and $\xi $ is a coupling parameter governing the strength and direction of the energy transfer. We show that by adding a factor $(1+w_{x})$ to the background energy transfer, the whole parameter space can be tested against all the data. We test three classes of interaction model using the latest astronomical data from the CMB, supernovae, baryon acoustic oscillations, redshift space distortions, weak lensing, cosmic chronometers, and the local Hubble constant. Precise constraints are found. We find in all interaction models that, as the value of Hubble constant decreases, the behavior of the dark energy equation of state shifts from phantom to quintessence type with its equation of state very close to that of a simple cosmological constant at the present time.
W. Yang, S. Pan and J. Barrow
Fri, 16 Jun 17
44/62
Comments: 15 pages, 15 figures and 1 Table