Traces of Anisotropic Quasi-Regular Structure in the SDSS Data

Abstract

The aim of this study is to search for quasi-periodical structures at moderate cosmological redshifts $z \la 0.5 $. We mainly use the SDSS DR7 data on the luminous red galaxies (LRGs) with redshifts $0.16 \leq z \leq 0.47$. At first, we analyze features (peaks) in the power spectra of radial (shell-like) distributions using separate angular sectors in the sky and calculate the power spectra within each sector. As a result, we found some signs of a large-scale anisotropic quasi-periodic structure detectable through 6 sectors out of a total of 144 sectors. These sectors are distinguished by large amplitudes of dominant peaks in their radial power spectra at wavenumbers $k$ within a narrow interval of $0.05 < k < 0.07$~h~Mpc$^{-1}$. Then, passing from a spherical coordinate system to a Cartesian one, we found a special direction such that the total distribution of LRG projections on it contains a significant ($\ga$5$\sigma$) quasi-periodical component. We assume that we are dealing with a signature of a quasi-regular structure with a characteristic scale $116 \pm 10$~h$^{-1}$~Mpc. Our assumption is confirmed by a preliminary analysis of the SDSS DR12 data.