GOLDRUSH. II. Clustering of galaxies at z ∼ 4-6 revealed with the half-million dropouts over the 100 deg2 area corresponding to 1 Gpc3

Yuichi Harikane, Masami Ouchi, Yoshiaki Ono, Shun Saito, Peter Behroozi, Surhud More, Kazuhiro Shimasaku, Jun Toshikawa, Yen Ting Lin, Masayuki Akiyama, Jean Coupon, Yutaka Komiyama, Akira Konno, Sheng Chieh Lin, Satoshi Miyazaki, Atsushi J. Nishizawa, Takatoshi Shibuya, John Silverman

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100 Citations (Scopus)


We present clustering properties from 579492 Lyman-break galaxies (LBGs) at z ∼ 4-6 over the 100 deg2 sky (corresponding to a 1.4 Gpc3 volume) identified in early data of the Hyper Suprime-Cam (HSC) Subaru Strategic Program survey.We derive angular correlation functions (ACFs) for the HSC LBGs with unprecedentedly high statistical accuracies at z ∼ 4-6, and compare them with the halo occupation distribution (HOD) models. We clearly identify significant ACF excesses in 10 < θ < 90, the transition scale between one- and two-halo terms, suggestive of the existence of the non-linear halo bias effect. Combining the HOD models and previous clustering measurements of faint LBGs at z ∼ 4-7, we investigate the dark matter halo mass (Mh) of the z ∼ 4-7 LBGs and its correlation with various physical properties including the star formation rate (SFR), the stellar-to-halo mass ratio (SHMR), and the dark matter accretion rate (Mh) over a wide mass range of Mh/M = 4 × 1010-4 × 1012. We find that the SHMR increases from z ∼ 4 to 7 by a factor of ∼4 at Mh - 1 × 1011M, while the SHMR shows no strong evolution in the similar redshift range at Mh - 1 × 1012M. Interestingly, we identify a tight relation of SFR/Mh-Mh showing no significant evolution beyond 0.15 dex in this wide mass range over z ∼ 4-7. This weak evolution suggests that the SFR/Mh-Mh relation is a fundamental relation in high-redshift galaxy formation whose star formation activities are regulated by the dark matter mass assembly. Assuming this fundamental relation, we calculate the cosmic star formation rate densities (SFRDs) over z = 0-10 (a.k.a. the Madau-Lilly plot). The cosmic SFRD evolution based on the fundamental relation agrees with the one obtained by observations, suggesting that the cosmic SFRD increase from z ∼ 10 to 4 - 2 (decrease from z ∼ 4-2 to 0) is mainly driven by the increase of the halo abundance (the decrease of the accretion rate).

Original languageEnglish
Article numberS11
JournalPublication of the Astronomical Society of Japan
Issue numberSpecial Issue 1
Publication statusPublished - 2018 Jan 1


  • Evolution-galaxies
  • Formation-galaxies
  • Galaxies
  • High-redshift


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