ﻻ يوجد ملخص باللغة العربية
In this letter, we implement a test of the standard law for the dark matter density evolution. For this purpose, only a flat universe and the validity of the FRW metric are assumed. A deformed dark matter density evolution law is considered, given by $rho_c(z) propto (1+z)^{3+epsilon}$, and constraints on $epsilon$ are obtained by using galaxy cluster gas mass fractions, and cosmic chronometers measurements. We find that $epsilon =0$ within 2$sigma$ c.l., in full agreement with other recent analyses.
We carry out a test of the cosmic distance duality relation using a sample of 52 SPT-SZ clusters, along with X-ray measurements from XMM-Newton. To carry out this test, we need an estimate of the luminosity distance ($D_L$) at the redshift of the clu
In this paper, we discuss a model-independent way to obtain the present dark matter density parameter ($Omega_{rm{c,0}}$) by combining gas mass fraction measurements in galaxy clusters ($f_{gas}$), type Ia supernovae (SNe Ia) observations and measure
Much focus was on the possible slowing down of cosmic acceleration under the dark energy parametrization. In the present paper, we investigate this subject using the Gaussian processes (GP), without resorting to a particular template of dark energy.
Using a new sub-sample of observed strong gravitational lens systems, for the first time, we present the equation for the angular diameter distance in the $y$-redshift scenario for cosmography and use it to test the cosmographic parameters. In additi
We derive a model for Sunyaev--Zeldovich data from a galaxy cluster which uses an Einasto profile to model the clusters dark matter component. This model is similar to the physical models for clusters previously used by the Arcminute Microkelvin Imag