Clustering of Lyman break galaxies at z = 4 and 5 in the Subaru Deep Field: Luminosity dependence of the correlation function slope

Nobunari Kashikawa, Makiko Yoshida, Kazuhiro Shimasaku, Masahiro Nagashima, Hideki Yahagi, Masami Ouchi, Yuichi Matsuda, Matthew A. Malkan, Mamoru Doi, Masanori Iye, Masaru Ajiki, Masayuki Akiyama, Hiroyasu Ando, Kentaro Aoki, Hisanori Furusawa, Tomoki Hayashino, Fumihide Iwamuro, Hiroshi Karoji, Naoto Kobayashi, Keiichi KodairaTadayuki Kodama, Yutaka Komiyama, Satoshi Miyazaki, Yoshihiko Mizumoto, Tomoki Morokuma, Kentaro Motohara, Takashi Murayama, Tohru Nagao, Kyoji Nariai, Kouji Ohta, Sadanori Okamura, Toshiyuki Sasaki, Yasunori Sato, Kazuhiro Sekiguchi, Yasuhiro Shioya, Hajime Tamura, Yoshiaki Taniguchi, Masayuki Umemura, Toru Yamada, Naoki Yasuda

Research output: Contribution to journalArticlepeer-review

74 Citations (Scopus)

Abstract

We explored the clustering properties of Lyman break galaxies at z = 4 and 5 with an angular two-point correlation function on the basis of the very deep and wide Subaru Deep Field data. We confirmed the previous result that the clustering strength of LBGs depends on the UV luminosity in the sense that brighter LBGs are more strongly clustered. In addition, we found an apparent dependence of the correlation function slope on UV luminosity for LBGs at both z = 4 and 5. More luminous LBGs have a steeper correlation function. The bias parameter was found to be a scale-dependent function for bright LBGs, whereas it appears to be almost scale-independent for faint LBGs. Luminous LBGs have a higher bias at smaller angular scales, which decreases as the scale increases. To compare these observational results, we constructed numerical mock LBG catalogs based on a semianalytic model of hierarchical clustering combined with high-resolution N-body simulation, carefully mimicking the observational selection effects. The luminosity functions and the overall correlation functions for LBGs at z = 4 and 5 predicted by this mock catalog were found to be almost consistent with the observation. The observed dependence of the clustering on UV luminosity was not reproduced by the model, unless subsamples of distinct halo mass were considered. That is, LBGs belonging to more massive dark halos had steeper and larger amplitude correlation functions. With this model, we found that LBG multiplicity in massive dark halos amplifies the clustering strength at small scales, which steepens the correlation function. The hierarchical clustering model could therefore be reconciled with the observed luminosity dependence of the correlation function if there is a tight correlation between UV luminosity and halo mass. Our finding that the slope of the correlation function depends on luminosity could be an indication that massive dark halos hosted multiple bright LBGs.

Original languageEnglish
Pages (from-to)631-647
Number of pages17
JournalAstrophysical Journal
Volume637
Issue number2 I
DOIs
Publication statusPublished - 2006 Feb 1

Keywords

  • Cosmology: observations
  • Cosmology: theory
  • Galaxies: highr-redshift
  • Large-scale structure of universe

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

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