We analyse the quasar two‐point correlation function (2pCF) within the redshift interval 0.8 < z < 2.2 using a sample of 52 303 quasars selected from the recent Sloan Digital Sky Survey Data Release 7. Our approach to the 2pCF uses the concept of a local Lorentz (Fermi) frame, for the determination of the distance between objects, and the permutation method of random catalogue generation. Assuming a spatially flat cosmological model with ΩΛ= 0.726, we have found that the real‐space 2pCF is fitted well with the power‐law model within the distance range 1 < σ < 35 h−1 Mpc with the correlation length r0= 5.85 ± 0.33 h−1 Mpc and the slope γ= 1.87 ± 0.07. The redshift‐space 2pCF is approximated with s0= 6.43 ± 0.63 h−1 Mpc and γ= 1.21 ± 0.24 for 1 < s < 10 h−1 Mpc, and s0= 7.37 ± 0.81 h−1 Mpc and γ= 1.90 ± 0.24 for 10 < s < 35 h−1 Mpc. For distances s > 10 h−1 Mpc, the parameter describing the large‐scale infall to density inhomogeneities is β= 0.63 ± 0.10 with the linear bias b = 1.44 ± 0.22, which marginally (within 2σ) agrees with the linear theory of cosmological perturbations. We discuss possibilities to obtain a statistical estimate of the random component of quasar velocities (different from the large‐scale infall). We note a slight dependence of the quasar velocity dispersion upon the 2pCF parameters in the region r < 2 Mpc.
Eighteen bright X-ray emitting galaxies were found in nearby filaments within SDSS region. Basic X-ray spectral parameters were estimated for these galaxies using power law model with photoelectric absorption. A close pair of X-ray galaxies was found.
Large-scale structure of Universe includes galaxy clusters connected by laments. Voids occupy the rest of cosmic volume. The search of any dependencities in lament structure can give answer to more general questions about origin of structures in the Universe. This becomes possible because, according to current picture of Universe, one could simulate the evolution of Universe until its very beginning or vice versa. One of the theories which describe the shape of largescale structures is adiabatic Zeldovich theory. This theory explain three-dimensional galaxy distribution as a set of thin pancakes which were formed from hot primordial gas under own gravitational pressure in the cosmological period of acîustic oscillations. According to cosmological hydrodynamical theories a number of computer simulations of LSS were performed to describe its properties. In this work we consider alternative variant of simulating the distribution of matter that is very similar to real. We simulated twodimensional galaxy distribution on the sky using random distributions of clusters and single galaxies. The main assumption was that matter clusterised to initial density uctuations with uniform distribution. According to Zeldovich theory, low-dimensional anisotropies should increase, that corresponds to appearance of laments in 2D case. Thus we generated a net of laments between clusters with certain length limits. Real galaxy distribution was simulated by random changing galaxy positions in laments and clusters. We generated radial distributions of galaxies in clusters taking into account the surrounding and add uniform distribution of isolated galaxies in voids. Our model has been coordinated with SDSS galaxy distribution with using two-point angular correlation function. Parameters of random distributions were found for the case of equality of correlation function slope for the model and for observational data.
Filaments are clearly visible in galaxy distributions, but they are hardly detected by computer algorithms. Most methods of filament detection can be used only with numerical simulations of a large-scale structure. New simple and effective methods for the real filament detection should be developed. The method of a smoothed galaxy density field was applied in this work to SDSS data of galaxy positions. Five concentric radial layers of 100 Mpc are appropriate for filaments detection. Two methods were tested for the first layer and one more method is proposed.
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