A new constraint on galaxy-halo connections of [O II] emitters via HOD modelling with angular clustering and luminosity functions from the Subaru HSC survey

TL;DR

This paper introduces a novel halo occupation distribution model incorporating galaxy luminosity to better understand the connection between emission-line galaxies and dark matter haloes, validated with Subaru HSC survey data.

Contribution

The new HOD framework integrates luminosity into galaxy occupation modeling, enabling joint analysis of angular clustering and luminosity functions for more accurate ELG-halo connection constraints.

Findings

Model successfully reproduces observed angular correlation functions and luminosity functions.

ELGs at z~1.4 likely evolve into Milky Way-like galaxies.

Provides more realistic ELG environment depiction compared to previous models.

Abstract

Establishing a robust connection model between emission-line galaxies (ELGs) and their host dark haloes is of paramount importance in anticipation of upcoming redshift surveys. We propose a novel halo occupation distribution (HOD) framework that incorporates galaxy luminosity, a key observable reflecting ELG star-formation activity, into the galaxy occupation model. This innovation enables prediction of galaxy luminosity functions (LFs) and facilitates joint analyses using both angular correlation functions (ACFs) and LFs. Using physical information from luminosity, our model provides more robust constraints on the ELG-halo connection compared to methods relying solely on ACF and number density constraints. Our model was applied to [O II]-emitting galaxies observed at two redshift slices at $z=1.193$ and $1.471$ from the Subaru Hyper Suprime-Cam PDR2. Our model effectively reproduces observed ACFs and LFs observed in both redshift slices. Compared to the established \citeauthor{geach12} HOD model, our approach offers a more nuanced depiction of ELG occupation across halo mass ranges, suggesting a more realistic representation of ELG environments. Our findings suggest that ELGs at $z\sim1.4$ may evolve into Milky-Way-like galaxies, as their inferred halo masses evolve accordingly based on the extended Press--Schechter formalism, highlighting their role as potential building blocks in galaxy formation scenarios. By incorporating the LF as a constraint linking galaxy luminosity to halo properties, our HOD model provides a more precise understanding of ELG-host halo relationships. Furthermore, this approach facilitates the generation of high-quality ELG mock catalogues of for future surveys. As the LF is a fundamental observable, our framework is potentially applicable to diverse galaxy populations, offering a versatile tool for analysing data from next-generation galaxy surveys.