An ALMA [C II] Survey of 27 Quasars at z > 5.94

Roberto Decarli, Fabian Walter, Bram P. Venemans, Eduardo Bañados, Frank Bertoldi, Chris Carilli, Xiaohui Fan, Emanuele Paolo Farina, Chiara Mazzucchelli, Dominik Riechers, Hans Walter Rix, Michael A. Strauss, Ran Wang, Yujin Yang

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225 Scopus citations


We present a survey of the [C ii] 158 μm line and underlying far-infrared (FIR) dust continuum emission in a sample of 27 quasars using the Atacama Large Millimeter Array (ALMA) at resolution. The [C ii] line was significantly detected (at -σ) in 23 sources (85%). We find typical line luminosities of L[C II]= 109-10 L⊙, and an average line width of ∼385 . The [C ii]-to-far-infrared luminosity ratios ([C ii]/FIR) in our sources span one order of magnitude, highlighting a variety of conditions in the star-forming medium. Four quasar host galaxies are clearly resolved in their [C ii] emission on a few kpc scales. Basic estimates of the dynamical masses of the host galaxies give masses between 2 ×1010 and 2 ×1011 , i.e., more than an order of magnitude below what is expected from local scaling relations, given the available limits on the masses of the central black holes (>3 × 108 M⊙, assuming Eddington-limited accretion). In stacked ALMA [C ii] spectra of individual sources in our sample, we find no evidence of a deviation from a single Gaussian profile. The quasar luminosity does not strongly correlate with either the [C ii] luminosity or equivalent width. This survey (with typical on-source integration times of 8 minutes) showcases the unparalleled sensitivity of ALMA at millimeter wavelengths, and offers a unique reference sample for the study of the first massive galaxies in the universe.

Original languageEnglish (US)
Article number97
JournalAstrophysical Journal
Issue number2
StatePublished - Feb 20 2018

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • galaxies: ISM
  • galaxies: high-redshift
  • quasars: emission lines
  • quasars: general


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