Evolution of Stellar-to-Halo Mass Ratio at z=0-7 Identified by Clustering Analysis with the Hubble Legacy Imaging and Early Subaru/Hyper Suprime-Cam Survey Data

TL;DR

This study analyzes the evolution of the stellar-to-halo mass ratio of Lyman break galaxies from redshift 0 to 7 using clustering analysis and halo occupation distribution modeling, revealing significant changes over cosmic time.

Contribution

It provides new measurements of halo masses and stellar-to-halo mass ratios at high redshifts, and compares these with theoretical models and abundance matching techniques.

Findings

SHMR decreases by a factor of ~2 from z~0 to 4

SHMR increases by a factor of ~4 from z~4 to 7

Clustering+HOD estimates agree with abundance matching within a factor of 3

Abstract

We present clustering analysis results from 10,381 Lyman break galaxies (LBGs) at z~ 4-7, identified in the Hubble legacy deep imaging and new complimentary large-area Subaru/Hyper Suprime-Cam data. We measure the angular correlation functions (ACFs) of these LBGs at z~4, 5, 6, and 7, and fit these measurements using halo occupation distribution (HOD) models that provide an estimate of halo masses, M_h~(1-20)x10^11 Msun. Our M_h estimates agree with those obtained by previous clustering studies in a UV-magnitude vs. M_h plane, and allow us to calculate stellar-to-halo mass ratios (SHMRs) of LBGs. By comparison with the z~0 SHMR, we identify evolution of the SHMR from z~0 to z~4, and z~4 to z~7 at the >98% confidence levels. The SHMR decreases by a factor of ~2 from z~0 to 4, and increases by a factor of ~4 from z~4 to 7. We compare our SHMRs with results of a hydrodynamic simulation and a semi-analytic model, and find that these theoretical studies do not predict the SHMR increase from z~4 to 7. We obtain the baryon conversion efficiency (BCE) of LBGs at z~4, and find that the BCE increases with increasing dark matter halo mass. Finally, we compare our clustering+HOD estimates with results from abundance matching techniques, and conclude that the M_h estimates of the clustering+HOD analyses agree with those of the simple abundance matching within a factor of 3, and that the agreement improves when using more sophisticated abundance matching techniques that include subhalos, incompleteness, and/or evolution in the star formation and stellar mass functions.