Consequences of dark matter-dark energy interaction on cosmological parameters derived from type Ia supernova data

Abstract

Models where the dark matter component of the Universe interacts with the dark energy field have been proposed as a solution to the cosmic coincidence problem, since in the attractor regime both dark energy and dark matter scale in the same way. In these models the mass of the cold dark matter particles is a function of the dark energy field responsible for the present acceleration of the Universe, and different scenarios can be parametrized by how the mass of the cold dark matter particles evolves with time. In this article we study the impact of a constant coupling between dark energy and dark matter on the determination of a redshift dependent dark energy equation of state w DE z and on the dark matter density today from SNIa data. We derive an analytical expression for the luminosity distance in this case. In particular, we show that the presence of such a coupling increases the tension between the cosmic microwave background data from the analysis of the shift parameter in models with constant w DE and SNIa data for realistic values of the present dark matter density fraction. Thus, an independent measurement of the present dark matter density can place constraints on models with interacting dark energy.

The Abell cluster A586 and the detection of violation of the equivalence principle

“…Such modification entails detectability on the evolution of the homogeneous geometry of the universe, as shown for the phenomenologically consistent unified model of DE and DM [10], the generalized Chaplygin gas (GCG) model [11] or for the more generic interacting model [7,12], but also on the quality of the self-gravitating equilibrium reached by large amounts of DM in clusters [3]. In Guo et al [7], the consistency of two DE-DM interaction models, a constant coupling model and a varying coupling model [13], with respect to the conjunction of data from Cosmic Microwave Background (CMB) radiation shift parameter [14], SNLS observations of type Ia Supernovae (SNIa) [15] and the Baryon Acoustic Oscillation (BAO) peaks in the SDSS [16].…”

Cosmic acceleration data and bulk-brane energy exchange

“…This requirement can be bypassed if a more general ansatz is adopted. A similar but qualitatively different from a physical viewpoint situation occurs in models which consider a dark matter -dark energy interaction (see [16] for some examples). In [17] we departed from the bulk fluid interpretation and assumed that the bulk pressure and energy exchange contributions are the dominant ones, while the dark radiation field is negligible in the range 0 ≤ z ≤ 1.…”

Observational constraints to a unified cosmological model

“…M is a constant depending on the Hubble constant H 0 , the speed of light c and the absolute magnitude of the standard supernova in the regarded band [54]. θ is the vector of parameters for the particular cosmological model under consideration.…”