Dark radiation from a unified dark fluid model

Abstract

We present a unified dark fluid model to describe the possible evolutionary behavior of $\Delta N_{\mathrm{eff}}$ in dark radiation. This model can be viewed as an interacting model for the dark sectors, in which dark matter interacts with dark radiation. We show that the evolution of $\Delta N_{\mathrm{eff}}$ can be nicely explained without some drawbacks, such as the blowup of $\Delta N_{\mathrm{eff}}$ and the non-vanishing interaction at the late time.

Comments: 12 pages, 4 figures, revised version accepted by PTEP