Subaru High-<i>z</i> Exploration of Low-Luminosity Quasars (SHELLQs). III. Star formation properties of the host galaxies at <i>z</i> ≳ 6 studied with ALMA

DOI DOI PDF 22 Citations 188 References
  • Takuma Izumi
    National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
  • Masafusa Onoue
    National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
  • Hikari Shirakata
    Department of Cosmosciences, Graduate School of Science, Hokkaido University, N10 W8, Kitaku, Sapporo, Hokkaido 060-0810, Japan
  • Tohru Nagao
    Research Center for Space and Cosmic Evolution, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
  • Kotaro Kohno
    Institute of Astronomy, Graduate School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan
  • Yoshiki Matsuoka
    Research Center for Space and Cosmic Evolution, Ehime University, 2-5 Bunkyo-cho, Matsuyama, Ehime 790-8577, Japan
  • Masatoshi Imanishi
    National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
  • Michael A Strauss
    National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
  • Nobunari Kashikawa
    National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
  • Andreas Schulze
    National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
  • John D Silverman
    Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583, Japan
  • Seiji Fujimoto
    Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8582, Japan
  • Yuichi Harikane
    Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8582, Japan
  • Yoshiki Toba
    Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan
  • Hideki Umehata
    The Open University of Japan, 2-11 Wakaba, Mihama-ku, Chiba 261-8586, Japan
  • Kouichiro Nakanishi
    National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
  • Jenny E Greene
    Department of Astrophysics, Princeton University, 4 Ivy Ln, Princeton, NJ 08544-1001, USA
  • Yoichi Tamura
    Division of Particle and Astrophysical Science, Graduate School of Science, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi 464-8602, Japan
  • Akio Taniguchi
    Institute of Astronomy, Graduate School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan
  • Yuki Yamaguchi
    Institute of Astronomy, Graduate School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan
  • Tomotsugu Goto
    Institute of Astronomy and Department of Physics, National Tsing Hua University, Hsinchu 30013, Taiwan
  • Yasuhiro Hashimoto
    Department of Earth Sciences, National Taiwan Normal University, Taipei 11677, Taiwan
  • Soh Ikarashi
    Kapteyn Astronomical Institute, University of Groningen, P.O. Box 800, 9700 AV Groningen, the Netherlands
  • Daisuke Iono
    National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
  • Kazushi Iwasawa
    ICREA and Institut de Ciències del Cosmos, Universitat de Barcelona, IEEC-UB, Martí i Franquès, 1, E-08028 Barcelona, Spain
  • Chien-Hsiu Lee
    National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan
  • Ryu Makiya
    Kavli Institute for the Physics and Mathematics of the Universe (WPI), The University of Tokyo Institutes for Advanced Study, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8583, Japan
  • Takeo Minezaki
    Institute of Astronomy, Graduate School of Science, The University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015, Japan
  • Ji-Jia Tang
    Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8582, Japan

Search this article

Description

<jats:title>Abstract</jats:title> <jats:p>We present our ALMA Cycle 4 measurements of the [C ii] emission line and the underlying far-infrared (FIR) continuum emission from four optically low-luminosity (M1450 &gt; −25) quasars at z ≳ 6 discovered by the Subaru Hyper Suprime Cam (HSC) survey. The [C ii] line and FIR continuum luminosities lie in the ranges $L_{\rm [C\,{\small {II}}]} = (3.8\mbox{--}10.2)\times 10^{8}\,L_{\odot }$ and LFIR = (1.2–2.0) × 1011 L$_{\odot}$, which are at least one order of magnitude smaller than those of optically-luminous quasars at z ≳ 6. We estimate the star formation rates (SFRs) of our targets as ≃ 23–40 M$_{\odot}$ yr−1. Their line and continuum-emitting regions are marginally resolved, and found to be comparable in size to those of optically-luminous quasars, indicating that their SFR or likely gas mass surface densities (key controlling parameter of mass accretion) are accordingly different. The $L_{\rm [C\,{\small {II}}]}/L_{\rm FIR}$ ratios of the hosts, ≃ (2.2–8.7) × 10−3, are fully consistent with local star-forming galaxies. Using the [C ii] dynamics, we derived their dynamical masses within a radius of 1.5–2.5 kpc as ≃ (1.4–8.2) × 1010 M$_{\odot}$. By interpreting these masses as stellar ones, we suggest that these faint quasar hosts are on or even below the star-forming main sequence at z ∼ 6, i.e., they appear to be transforming into quiescent galaxies. This is in contrast to the optically-luminous quasars at those redshifts, which show starburst-like properties. Finally, we find that the ratios of black hole mass to host galaxy dynamical mass of most of the low-luminosity quasars, including the HSC ones, are consistent with the local value. The mass ratios of the HSC quasars can be reproduced by a semi-analytical model that assumes merger-induced black hole host galaxy evolution.</jats:p>

Journal

Citations (22)*help

See more

References(188)*help

See more

Related Projects

See more

Keywords

Details 詳細情報について

Report a problem

Back to top