A new interacting two-fluid model and its consequences

Abstract

In the background of a homogeneous and isotropic spacetime with zero spatial\ncurvature, we consider interacting scenarios between two barotropic fluids, one\nis the pressureless dark matter (DM) and the other one is dark energy (DE), in\nwhich the equation of state (EoS) in DE is either constant or time dependent.\nIn particular, for constant EoS in DE, we show that the evolution equations for\nboth fluids can be analytically solved. For all these scenarios, the model\nparameters have been constrained using the current astronomical observations\nfrom Type Ia Supernovae, Hubble parameter measurements, and baryon acoustic\noscillations distance measurements. Our analysis shows that both for constant\nand variable EoS in DE, a very small but nonzero interaction in the dark sector\nis favored while the EoS in DE can predict a slight phantom nature, i.e. the\nEoS in DE can cross the phantom divide line `$-1$'. On the other hand, although\nthe models with variable EoS describe the observations better, but the Akaike\nInformation Criterion supports models with minimal number of parameters.\nHowever, it is found that all the models are very close to the $\\Lambda$CDM\ncosmology.\n