Quasi-periodical features in the distribution of Luminous Red Galaxies

TL;DR

This study identifies quasi-periodic features in the radial distribution of Luminous Red Galaxies from SDSS, revealing characteristic scales consistent with baryon acoustic oscillations and highlighting the importance of analysis methods.

Contribution

It provides the first detailed analysis of quasi-periodicities in LRG distributions, linking observed scales to cosmological models and BAO features.

Findings

Detected significant quasi-periodicities at ~135 and ~101 h^{-1} Mpc scales.

Confirmed the dominant scale aligns with baryon acoustic oscillations.

Showed that significance levels depend on data smoothing and fluctuation characteristics.

Abstract

A statistical analysis of radial distributions of Luminous Red Galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS DR7) catalogue within an interval $0.16 \leq z \leq 0.47$ is carried out. We found that the radial distribution of $\sim$ 106,000 LRGs incorporates a few quasi-periodical components relatively to a variable $\eta$, dimensionless line-of-sight comoving distance calculated for the $\Lambda$CDM cosmological model. The most significant peaks of the power spectra are obtained for two close periodicities corresponding to the spatial comoving scales $(135 \pm 12) h^{-1}$ Mpc and $(101 \pm 6)h^{-1}$ Mpc. The latter one is dominant and consistent with the characteristic scale of the baryon acoustic oscillations. We analyse also the radial distributions of two other selected LRG samples: $\sim$ 33,400 bright LRGs ($-23.2 < M \leq -21.8$) and $\sim$ 60,300 all LRGs within a rectangle region on the sky, and show differences of the quasi-periodical features characteristic for different samples. Being confirmed the results would allow to give preference of the spatial against temporal models which could explain the quasi-periodicities discussed here. As a caveat we show that estimations of the significance levels of the peaks strongly depend on a smoothed radial function (trend) as well as characteristics of random fluctuations.