Constructing the Emission-line Galaxy–Host Halo Connection through Auto and Cross Correlations

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, 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 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.