# Power-spectrum simulations of radial redshift distributions

## TL;DR

This paper uses simulations based on a simple model of Gaussian fields modulated in k-space to study how radial distributions of cosmological objects exhibit power spectrum features, especially BAO, and revises previous significance estimates.

## Contribution

It introduces a simulation framework to analyze the effects of modulation functions on power spectra of radial distributions, clarifying the stochastic nature of observed quasi-periodic components.

## Key findings

- Radial distributions show quasi-periodic components with characteristic scales around 100 h^{-1} Mpc.
- Significance of power spectrum peaks was overestimated in previous analyses.
- Simulated results align well with observed properties of brightest cluster galaxies.

## Abstract

On the base of the simplest model of a modulation of 3D Gaussian field in $k$-space we produce a set of simulations to bring out the effects of a modulating function $f_{\rm mod} (k)=f_1 (k) + f_2 (k)$ on power spectra of radial (shell-like) distributions of cosmological objects, where a model function $f_1 (k)$ reproduces the smoothed power spectrum of underlying 3D density fluctuations, while $f_2 (k)$ is a wiggling function imitating the baryon acoustic oscillations (BAO). It is shown that some excess of realizations of simulated radial distributions actually displays quasi-periodical components with periods about a characteristic scale $2\pi/k \sim 100~h^{-1}$~Mpc detected as power-spectrum peaks in vicinity of the first maximum of the modulation function $f_2 (k)$. We revised our previous estimations of the significance of such peaks and found that they were largely overestimated. Thereby quasi-periodical components appearing in some radial distributions of matter are likely to be stochastic (rather than determinative), while the amplitudes of the respective spectral peaks can be quite noticeable. They are partly enhanced by smooth part of the modulating function $f_1(k)$ and, to a far lesser extent, by effects of the BAO (i.e. $f_2(k)$). The results of the simulations match quite well with statistical properties of the radial distributions of the brightest cluster galaxies (BCGs).