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 (Ωc,0) by combining gas mass fraction measurements in galaxy clusters (fgas), type Ia supernovae (SNe Ia) observations and measurements of the cosmic baryon abundance from observations of absorption systems at high redshifts. Our estimate is Ωc,0 = 0.244 ± 0.013 (1σ). By considering the latest local measurement of the Hubble constant, we obtain ΩM,0 = 0.285 ± 0.013 (1σ) 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 fgas and SNe Ia observations to detect a possible non-minimal coupling in the cosmological dark sector.