The Galaxy-Halo Connection in High-redshift Universe: Details and Evolution of Stellar-to-halo Mass Ratios of Lyman Break Galaxies on CFHTLS Deep Fields

We present the results of clustering analyses of Lyman break galaxies (LBGs) at z ∼ 3, 4, and 5 using the final data release of the Canada-France-Hawaii Telescope Legacy Survey (CFHTLS). Deep- and wide-field images of the CFHTLS Deep Survey enable us to obtain sufficiently accurate two-point angular correlation functions to apply a halo occupation distribution analysis. The mean halo masses, calculated as 〈M_h〉 10^11.7 -10^12.8 h^-1 M⊙, increase with the stellar-mass limit of LBGs. The threshold halo mass to have a central galaxy, M<_min<, follows the same increasing trend as the low-z results, whereas the threshold halo mass to have a satellite galaxy, M1, shows higher values at z = 3-5 than z = 0.5-1.5, over the entire stellar mass range. Satellite fractions of dropout galaxies, even at less massive halos, are found to drop sharply, from z = 2 down to less than 0.04, at z = 3-5. These results suggest that satellite galaxies form inefficiently within dark halos at z = 3-5, even for less massive satellites with M⊙ < 10¹⁰ M⊙. We compute stellar-to-halo mass ratios (SHMRs) assuming a main sequence of galaxies, which is found to provide SHMRs consistent with those derived from a spectral energy distribution fitting method. The observed SHMRs are in good agreement with model predictions based on the abundance-matching method, within 1σ confidence intervals. We derive observationally, for the first time, M<_h<<^pivot<, which is the halo mass at a peak in the star-formation efficiency, at 3 < z < 5, and it shows a small increasing trend with cosmic time at z > 3. In addition, M_h pivot and its normalization are found to be almost unchanged during 0 < z < 5. Our study provides observational evidence that galaxy formation is ubiquitously most efficient near a halo mass of M_h ∼ 10¹² M⊙ over cosmic time.