The subaru/XMM-Newton Deep Survey (SXDS). IV. Evolution of lyα emitters from z = 3.1 to 5.7 in the 1 deg2 field: Luminosity functions and AGN

Masami Ouchi, Kazuhiro Shimasaku, Masayuki Akiyama, Chris Simpson, Tomoki Saito, Yoshihiro Ueda, Hisanori Furusawa, Kazuhiro Sekiguchi, Toru Yamada, Tadayuki Kodama, Nobunari Kashikawa, Sadanori Okamura, I. Y.E. Masanori, Tadapumi Takata, Michitoshi Yoshida, Makiko Yoshida

Research output: Contribution to journalArticlepeer-review

468 Citations (Scopus)


We present luminosity functions (LFs) and various properties of Lyα emitters (LAEs) at z = 3.1, 3.7, and 5.7, in a 1 deg2 sky of the Subaru/XMM-Newton Deep Survey (SXDS) Field. We obtain a photometric sample of 858 LAE candidates based on deep Subaru Suprime-Cam imaging data and a spectroscopic sample of 84 confirmed LAEs from Subam FOCAS and VLT VIMOS spectroscopy in a survey volume of ∼106 Mpc3 with a limiting Lyα luminosity of ∼3 × 1042 ergs s -1. We derive the LFs of the Lyα and UV continuum (≃1500 Å) for each redshift, taking into account the statistical error and the field-to-field variation. We find that the apparent Lyα LF shows no significant evolution between z = 3.1 and 5.7 within factors of 1.8 and 2.7 in L* and φ*, respectively. On the other hand, the UV LF of LAEs increases from z = 3.1 to 5.7, indicating that galaxies with Lyα emission are more common at earlier epochs. We identify six LAEs with AGN activities from our spectra combined with VLA, Spitzer, and XMM-Newton data. Among the photometrically selected LAEs at z = 3.1 and 3.7, only ≃1% show AGN activities, while the brightest LAEs with log L(Lyα) ≥ 43.4-43.6 ergs s-1 appear to always host AGNs. Our LAEs are bluer in UV-continuum color than dropout galaxies, suggesting lower extinction and/or younger stellar populations. Our stacking analyses provide upper limits to the radio luminosity and the ∫He II/∫Lyα line fraction and constrain the hidden star formation (+low-luminosity AGN) and the primordial population in LAEs.

Original languageEnglish
Pages (from-to)301-330
Number of pages30
JournalAstrophysical Journal, Supplement Series
Issue number2
Publication statusPublished - 2008 Jun


  • Cosmology: observations
  • Galaxies: formation
  • Galaxies: high-redshift

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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