The dynamics of expansion and large scale structure formation in the multicomponent Universe with dark energy modeled by the minimally coupled scalar field with generalized linear barotropic equation of state (EoS) are analyzed. It is shown that the past dynamics of expansion and future of the Universe -eternal accelerated expansion or turnaround and collapse -are completely defined by the current energy density of a scalar field and relation between its current and early EoS parameters. The clustering properties of such models of dark energy and their imprints in the power spectrum of matter density perturbations depend on the same relation and, additionally, on the "effective sound speed" of a scalar field, defined by its Lagrangian. It is concluded that such scalar fields with different values of these parameters are distinguishable in principle. This gives the possibility to constrain them by confronting the theoretical predictions with the corresponding observational data. For that we have used the 7-year WMAP data on CMB anisotropies, the Union2 dataset on Supernovae Ia and SDSS DR7 data on luminous red galaxies (LRG) space distribution. Using the Markov Chain Monte Carlo technique the marginalized posterior and mean likelihood distributions are computed for the scalar fields with two different Lagrangians: Klein-Gordon and Dirac-Born-Infeld ones. The properties of such scalar field models of dark energy with best fitting parameters and uncertainties of their determination are also analyzed in the paper. PACS numbers: 95.36.+x, 98.80.-k Keywords: cosmology: dark energy-scalar field-cosmic microwave background-large scale structure of Universe-cosmological parameters

The locations and amplitudes of three acoustic peaks and two dips in the BOOMERANG, MAXIMA, and DASI measurements of the cosmic microwave background (CMB) anisotropy power spectra as well as their statistical confidence levels are determined in a model-independent way. It is shown that the BOOMERANG 2001 data from Netterfield and coworkers fix the location and amplitude of the first acoustic peak at more than 3 confidence. The next two peaks and dips are determined at a confidence level above 1 but below 2 . The locations and amplitudes of the first three peaks and two dips are l p 1 ¼ 212 AE 17,(1 errors include statistical and systematic errors). The MAXIMA and DASI experiments give similar values for the extrema that they determine. For MAXIMA these are the first and third peaks, for DASI the first and second peaks and the first dip. Moreover, the locations and amplitudes of the extrema determined from the combined data of all experiments are quite close to the corresponding values extracted from the BOOMERANG data alone. In order to use these data in a fast search for cosmological parameters, an accurate analytic approximation to calculate CMB peak and dip positions and amplitudes in mixed dark matter models with cosmological constant and curvature is derived and tested. The determined cosmological parameters from the CMB acoustic extrema data show good agreement with other determinations, especially with the baryon content as deduced from standard nucleosynthesis constraints, as shown by Burles and coworkers. These data supplemented by constraints from direct measurements of some cosmological parameters and data on large-scale structure lead to a best-fit model that agrees with practically all the used experimental data within 1 . The best-fit parameters are à ¼ 0

The possibility of distinguishing scalar field models of dark energy with different Lagrangians and time variable equation of state parameter by available observational data is analyzed. The multicomponent cosmological models with the scalar field with either Klein-Gordon or Dirac-Born-Infeld Lagrangians as dark energy and the monotonic decreasing and increasing equation of state parameters are considered. It is concluded that scalar field models of dark energy with decreasing and increasing EoS parameters should be distinguishable at the accuracy level of forthcoming observational data. The Lagrangians of scalar fields could be distinguished by expected observational data (Planck, SDSS etc.) in the case of decreasing EoS parameter, but are practically indistinguishable in the case of the increasing one.

The galaxy data provided by COSMOS survey for 1 • × 1 • field of sky are analysed by methods of complex networks. Three galaxy samples (slices) with redshifts ranging within intervals 0.88÷0.91, 0.91÷0.94 and 0.94÷0.97 are studied as two-dimensional projections for the spatial distributions of galaxies. We construct networks and calculate network measures for each sample, in order to analyse the network similarity of different samples, distinguish various topological environments, and find associations between galaxy properties (colour index and stellar mass) and their topological environments.Results indicate a high level of similarity between geometry and topology for different galaxy samples and no clear evidence of evolutionary trends in network measures. The distribution of local clustering coefficient C manifests three modes which allow for discrimination between stand-alone singlets and dumbbells (0 ≤ C ≤ 0.1), intermediately packed (0.1 < C < 0.9) and clique (0.9 ≤ C ≤ 1) like galaxies.Analysing astrophysical properties of galaxies (colour index and stellar masses), we show that distributions are similar in all slices, however weak evolutionary trends can also be seen across redshift slices. To specify different topological environments we have extracted selections of galaxies from each sample according to different modes of C distribution. We have found statistically significant associations between evolutionary parameters of galaxies and selections of C: the distribution of stellar mass for galaxies with interim C differ from the corresponding distributions for stand-alone and clique galaxies, and this difference holds for all redshift slices. The colour index realises somewhat different behaviour.

Проаналiзовано розвиток амплiтуди релiктових ґравiтацiйних хвиль (РҐХ), зґенерованих у ранньому Всесвiтi. Наведено аналiтичну апроксимацiю кутового спектра потужности флюктуацiй температури релiктового електромагнетного випромiнювання (РЕВ), зумовлених такими ґравiтацiйними хвилями через ефект Сакса-Вольфа. Отримано оцiнку найбiльш iмовiрного значення цiєї амплiтуди на основi даних спостережень анiзотропiї температури релiктового електромагнетного випромiнювання, одержаних в експериментах COBE, WMAP i BOOMERanG, та даних спостережень великомасштабної структури Всесвiту. Показано, що сукупнiсть сучасних даних про великомасштабну структуру Всесвiту та РЕВ указує на вiдсутнiсть або малу амплiтуду релiктових ґравiтацiйних хвиль, так що на 95% рiвнi достовiрности їх внесок у квадрупольну компоненту анiзотропiї температури релiктового випромiнювання не перевищує 60% навiть при екстремально рiзкому (nt = −1) спектрi потужности тензорних збурень. Для плоского спектра (nt = 0) та моделей з nt ∼ (ns − 1) цей внесок не перевищує 18% на рiвнi достовiрности 2σ.Ключовi слова: релiктовi ґравiтацiйнi хвилi, релiктове електромагнетне випромiнювання, великомасштабна структура Всесвiту.