Maturing Satellite Kinematics into a Competitive Probe of the Galaxy-Halo Connection

TL;DR

This paper advances the use of satellite galaxy kinematics to more accurately probe the galaxy-halo connection, addressing previous discrepancies and developing a robust analysis method tested on mock data.

Contribution

It introduces an improved, robust analysis framework for satellite phase-space distributions to better constrain the galaxy-halo relation from spectroscopic surveys.

Findings

Constraints are competitive with clustering and lensing.

Model assumptions significantly impact mass estimates.

Method tested successfully on realistic mock catalogues.

Abstract

The kinematics of satellite galaxies moving in a dark matter halo are a direct probe of the underlying gravitational potential. Thus, the phase-space distributions of satellites represent a powerful tool to determine the galaxy-halo connection from observations. By stacking the signal of a large number of satellite galaxies this potential can be unlocked even for haloes hosting a few satellites on average. In this work, we test the impact of various modelling assumptions on constraints derived from analysing satellite phase-space distributions in the non-linear, 1-halo regime. We discuss their potential to explain the discrepancy between average halo masses derived from satellite kinematics and gravitational lensing previously reported. Furthermore, we develop an updated, more robust analysis to extract constraints on the galaxy-halo relation from satellite properties in spectroscopic galaxy surveys such as the SDSS. We test the accuracy of this approach using a large number of realistic mock catalogues. Furthermore, we find that constraints derived from such an analysis are complementary and competitive with respect to the commonly used galaxy clustering and galaxy-galaxy lensing observables.