Impacts of satellite galaxies on the redshift-space distortions

TL;DR

This paper investigates how satellite galaxies influence redshift-space distortions in galaxy surveys, revealing their significant role in higher multipole spectra and implications for cosmic growth measurements.

Contribution

It demonstrates the importance of satellite galaxies in multipole power spectra and introduces a halo model to understand their impact on redshift-space distortions.

Findings

Satellite galaxies significantly affect higher multipole spectra.

Small-scale multipole spectra help calibrate satellite Finger of God effects.

Fiber collision impacts satellite counts and multipole spectra.

Abstract

We study the impacts of the satellite galaxies on the redshift-space distortions. In our multipole power spectrum analysis of the luminous red galaxies (LRGs) samples of the Sloan Digital Sky Survey (SDSS), we have clearly detected the non-zero signature of the hexadecapole and tetrahexadecapole spectrum, which almost disappears in the power spectrum with the sample of the brightest LRGs only. We thus demonstrate that the satellite LRGs in multiple systems make a significant contribution to the multipole power spectrum though its fraction is small. The behavior can be understood by a simple halo model, in which the one-halo term, describing the Finger of God (FoG) effect from the satellite galaxies, makes the dominant contribution to the higher multipole spectra. We demonstrate that the small-scale information of higher multipole spectrum is useful for calibrating the satellite FoG effect and improves the measurement of the cosmic growth rate dramatically. We further demonstrate that the fiber collision in the galaxy survey influences the one-halo term and the higher multipole spectra, because the number of satellite galaxies in the halo occupation distribution (HOD) is changed. We also discuss about the impact of satellite galaxies on future high-redshift surveys targeting the H-alpha emitters.