Dark Energy and Large-Scale Structure of the Universe

The evolution of matter density perturbations in two-component model of the Universe consisting of dark energy (DE) and dust-like matter (M) is considered. We have analyzed it for two kinds of DE with $\omega\ne -1$: a) unperturbed energy density and b) perturbed one (uncoupled with matter). For these cases the linear equations for evolution of the gauge-invariant amplitudes of matter density perturbations are presented. It is shown that in the case of unperturbed energy density of DE the amplitude of matter density perturbations grow slightly faster than in the second case.Comment: 4 pages, 1 figure, submitted to the proceedings of international conference "Astronomy in Ukraine - Past, Present, Future", July 15-17, Kiev, Ukrain

Non-linear power spectra of dark and luminous matter in halo model of structure formation

The late stages of large-scale structure evolution are treated semi-analytically within the framework of modified halo model. We suggest simple yet accurate approximation for relating the non-linear amplitude to linear one for spherical density perturbation. For halo concentration parameter, $c$, a new computation technique is proposed, which eliminates the need of interim evaluation of the $z_{col}$. Validity of the technique is proved for $\Lambda$CDM and $\Lambda$WDM cosmologies. Also, the parameters for Sheth-Tormen mass function are estimated. The modified and extended halo model is applied for determination of non-linear power spectrum of dark matter, as well as for galaxy power spectrum estimation. The semi-analytical techniques for dark matter power spectrum are verified by comparison with data from numerical simulations. Also, the predictions for the galaxy power spectra are confronted with 'observed' data from PSCz and SDSS galaxy catalogs, good accordance is found.Comment: 18 pages, 8 figures; major changes from the previous version; accepted for publivation in Phys. Rev.