Construct the emission line galaxy-host halo connection through auto and cross correlations

TL;DR

This paper presents a new method to connect emission line galaxies with their dark matter halos using correlation functions, enabling accurate modeling without assuming a traditional halo occupation distribution.

Contribution

The authors introduce a parameter-free approach to establish the ELG-halo connection using auto and cross correlations, improving mock catalog generation for galaxy surveys.

Findings

Successfully reproduces ELG and galaxy correlation functions

Establishes an accurate ELG-halo connection without assuming a parametric HOD

Provides a simple HOD description for ELGs

Abstract

We investigate the [O\,II] emission line galaxy (ELG)-host halo connection via auto and cross correlations, and propose a concise and effective method to populate ELGs in dark matter halos without assuming a parameterized halo occupation distribution (HOD) model. Using the observational data from VIMOS Public Extragalactic Redshift Survey (VIPERS), we measure the auto and cross correlation functions between ELGs selected by [O\,II] luminosity and normal galaxies selected by stellar mass. Combining the stellar-halo mass relation (SHMR) derived for the normal galaxies and the fraction of ELGs observed in the normal galaxy population, we demonstrate that we can establish an accurate ELG-halo connection. With the ELG-halo connection, we can accurately reproduce the auto and cross correlation functions of ELGs and normal galaxies both in real-space and in redshift-space, once the satellite fraction is properly reduced. Our method provides a novel strategy to generate ELG mock catalogs for ongoing and upcoming galaxy redshift surveys. We also provide a simple description for the HOD of ELGs.