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Title: FIRST CONNECTION BETWEEN COLD GAS IN EMISSION AND ABSORPTION: CO EMISSION FROM A GALAXY–QUASAR PAIR

We present the first detection of molecular emission from a galaxy selected to be near a projected background quasar using the Atacama Large Millimeter/submillimeter Array (ALMA). The ALMA detection of CO(1−0) emission from the z = 0.101 galaxy toward quasar PKS 0439–433 is coincident with its stellar disk and yields a molecular gas mass of M{sub mol} ≈ 4.2 × 10{sup 9} M{sub ⊙} (for a Galactic CO-to-H{sub 2} conversion factor), larger than the upper limit on its atomic gas mass. We resolve the CO velocity field, obtaining a rotational velocity of 134 ± 11 km s{sup −1} and a resultant dynamical mass of ≥4 × 10{sup 10} M{sub ⊙}. Despite its high metallicity and large molecular mass, the z = 0.101 galaxy has a low star formation rate, implying a large gas consumption timescale, larger than that typical of late-type galaxies. Most of the molecular gas is hence likely to be in a diffuse extended phase, rather than in dense molecular clouds. By combining the results of emission and absorption studies, we find that the strongest molecular absorption component toward the quasar cannot arise from the molecular disk, but is likely to arise from diffuse gas in the galaxy’s circumgalactic medium. Our results emphasize the potential of combining molecular and stellarmore » emission line studies with optical absorption line studies to achieve a more complete picture of the gas within and surrounding high-redshift galaxies.« less
Authors:
;  [1] ; ; ;  [2] ;  [3] ; ;  [4] ;  [5] ;  [6]
  1. Department of Astronomy and Astrophysics, UCO/Lick Observatory, University of California, 1156 High Street, Santa Cruz, CA 95064 (United States)
  2. European Southern Observatory, Karl-Schwarzschild-strasse 2, D-85748 Garching bei München (Germany)
  3. National Centre for Radio Astrophysics, Tata Institute of Fundamental Research, Pune 411007 (India)
  4. Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark)
  5. Observatoire de Genève, Université de Genève, 51 Ch. des Maillettes, 1290 Sauverny (Switzerland)
  6. Australian Astronomical Observatory, P.O. Box 915, North Ryde, NSW 1670 (Australia)
Publication Date:
OSTI Identifier:
22518525
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal Letters; Journal Volume: 820; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION; CARBON MONOXIDE; CLOUDS; DETECTION; EMISSION; GALAXIES; HYDROGEN; MASS; METALLICITY; MOLECULES; QUASARS; RED SHIFT; STARS; VELOCITY