An estimate of the dark matter density from galaxy clusters and supernovae data

Abstract

In this paper, we discuss a model-independent way to obtain the present dark matter density parameter (${\Omega }_{\mathrm{c},0}$) by combining gas mass fraction measurements in galaxy clusters ($f_{gas}$), type Ia supernovae (SNe Ia) observations and measurements of the cosmic baryon abundance from observations of absorption systems at high redshifts. Our estimate is ${\Omega }_{\mathrm{c},0}=0.244\pm 0.013$ ($1\sigma$). By considering the latest local measurement of the Hubble constant, we obtain ${\Omega }_{\mathrm{M},0}=0.285\pm 0.013$ ($1\sigma$) for the total matter density parameter. We also investigate departures of the evolution of the dark matter density with respect to the usual $a^{-3}$ scaling, as usual in interacting models of dark matter and dark energy. As the current data cannot confirm or rule out such an interaction, we perform a forecast analysis to estimate the necessary improvements in number and accuracy of upcoming $f_{gas}$ and SNe Ia observations to detect a possible non-minimal coupling in the cosmological dark sector.

JCAP Accepted, 7 pages, 4 figures