Hyper-luminous dust-obscured galaxies discovered by the Hyper Suprime-Cam on Subaru and WISE

Yoshiki Toba, Tohru Nagao, Michael A. Strauss, Kentaro Aoki, Tomotsugu Goto, Masatoshi Imanishi, Toshihiro Kawaguchi, Yuichi Terashima, Yoshihiro Ueda, James Bosch, Kevin Bundy, Yoshiyuki Doi, Hanae Inami, Yutaka Komiyama, Robert H. Lupton, Hideo Matsuhara, Yoshiki Matsuoka, Satoshi Miyazaki, Tomoki Morokuma, Fumiaki NakataNagisa Oi, Masafusa Onoue, Shinki Oyabu, Paul Price, Philip J. Tait, Tadafumi Takata, Manobu M. Tanaka, Tsuyoshi Terai, Edwin L. Turner, Tomohisa Uchida, Tomonori Usuda, Yousuke Utsumi, Yoshihiko Yamada, Shiang Yu Wang

Research output: Contribution to journalArticle

16 Scopus citations

Abstract

We present the photometric properties of a sample of infrared (IR) bright dust-obscured galaxies (DOGs). Combining wide and deep optical images obtained with the Hyper Suprime-Cam on the Subaru Telescope and all-sky mid-IR (MIR) images taken with Wide-Field Infrared Survey Explorer, we discovered 48 DOGs with i - Ks > 1.2 and i - [22] > 7.0, where i, Ks, and [22] represent AB magnitude in the i-band, Ks-band, and 22 μm, respectively, in the GAMA 14 hr field (∼ 9 deg2). Among these objects, 31 (∼ 65%) show power-law spectral energy distributions (SEDs) in the near-IR (NIR) and MIR regime, while the remainder show an NIR bump in their SEDs. Assuming that the redshift distribution for our DOGs sample is Gaussian, with mean and sigma z = 1.99 ± 0.45, we calculated their total IR luminosity using an empirical relation between 22 μm luminosity and total IR luminosity. The average value of the total IR luminosity is (3.5 ± 1.1) × 1013 L⊙, which classifies them as hyper-luminous infrared galaxies. We also derived the total IR luminosity function (LF) and IR luminosity density (LD) for a flux-limited subsample of 18 DOGs with 22 μm flux greater than 3.0 mJy and with i-band magnitude brighter than 24 AB magnitude. The derived space density for this subsample is log Φ = -6.59 ± 0.11 [Mpc-3]. The IR LF for DOGs including data obtained from the literature is fitted well by a double-power law. The derived lower limit for the IR LD for our sample is ρIR∼3.8 × 107 [L⊙ Mpc-3] and its contributions to the total IR LD, IR LD of all ultra-luminous infrared galaxies, and that of all DOGs are > 3%, > 9%, and > 15%, respectively.

Original languageEnglish (US)
Article number86
JournalPublications of the Astronomical Society of Japan
Volume67
Issue number5
DOIs
StatePublished - Jun 30 2015

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science

Keywords

  • catalogs
  • galaxies: active
  • galaxies: luminosity function mass function
  • infrared: galaxies
  • methods: statistical

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