Cosmological constraints on parametrized interacting dark energy

Publication date: Available online 3 December 2018Source: Physics of the Dark UniverseAuthor(s): R. von Marttens, L. Casarini, D.F. Mota, W. ZimdahlAbstractWe reconsider the dynamics of the Universe in the presence of interactions in the cosmological dark sector. A class of interacting models is introduced via a real function fr of the ratio r between the energy densities of the (pressureless) cold dark matter (CDM) and dark energy (DE). The subclass of models for which the ratio r depends only on the scale factor is shown to be equivalent to unified models of the dark sector, i.e. models for which the CDM and DE components can be combined in order to form a unified dark fluid. For specific choices of the function fr we recover several models already studied in the literature. We analyse various special cases of this type of interacting models using a suitably modified version of the CLASS code combined with MontePython in order to constrain the parameter space with the data from supernova of type SNe Ia (JLA), the Hubble constant H0, cosmic chronometers (CC), baryon acoustic oscilations (BAO) and data from the Planck satellite (Planck TT). Our analysis shows that even if data from the late Universe ( H0, SNe Ia and CC) indicate an interaction in the dark sector, the data related to the early Universe (BAO and Planck TT) constrain this interaction substantially, in particular for cases in which the background dynamics is strongly affected.

Source: Physics of the Dark Universe - December 4, 2018 Category: Physics Source Type: research