arXiv subjects
Publications and source records attributed to N. A. Arhipova.
We modify the Press-Schechter formalism to calculate the mass function of gravitationally bounded objects in a local Universe with size $L> 10h^{-1}$Mpc, i.e. separately in voids ($Ω_{m,L}<Ω_m$) and superclusters ($Ω_{m,L}>Ω_m$). The dependence of the abundance of gravitationally bounded objects on local matter density is analyzed.
The time evolution of the number density of galaxy clusters and their mass and temperature functions are used to constrain cosmological parameters in the spatially flat dark matter models containing a fraction of hot particles (massive neutrino) additional to cold and baryonic matter. We test the modified MDM models with cosmic gravitational waves and show that they neither pass the cluster evolution test nor reproduce the observed height of the first acoustic peak in $ΔT/T$ spectrum, and therefore should be ruled out. The models with a non-zero cosmological constant are in better agreement with observations. We estimate the free cosmological parameters in $Λ$MDM with a negligible abundance of gravitational waves, and find that within the parameter ranges $h\in (0.6, 0.7)$, $n\in (0.9, 1.1)$, (i) the value of $Ω_Λ$ is strongly affected by a small fraction of hot dark matter, $f_ν\equivΩ_ν/Ω_m\in (0, 0.2)$: $0.45 <Ω_Λ<0.7$ ($1σ$ CL), and (ii) the redshift evolution of galaxy clusters alone reveals the following explicit correlation between $Ω_Λ$ and $f_ν$: $Ω_Λ+0.5f_ν=0.65\pm 0.1$. The present accuracy of observational data allows only to bound the fraction of hot matter, $f_ν\in (0, 0.2)$ (the number of massive neutrino species remains undelimited, $N_ν=1, 2, 3$).