A molecular line scan in the Hubble deep field north: Constraints on the co luminosity function and the cosmic H{sub 2} density
- Max-Planck Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg (Germany)
- Laboratoire AIM, CEA/DSM-CNRS-Universite Paris Diderot, Irfu/Service d'Astrophysique, CEA Saclay, Orme des Merisiers, F-91191 Gif-sur-Yvette cedex (France)
- NRAO, Pete V. Domenici Array Science Center, P.O. Box O, Socorro, NM 87801 (United States)
- National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)
- Cornell University, 220 Space Sciences Building, Ithaca, NY 14853 (United States)
- Astronomy Department, California Institute of Technology, MC105-24, Pasadena, CA 91125 (United States)
- Steward Observatory, University of Arizona, 933 North Cherry Street, Tucson, AZ 85721 (United States)
- European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Vitacura, Santiago (Chile)
- Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109 (United States)
- Argelander Institute for Astronomy, University of Bonn, Auf dem Hügel 71, D-53121 Bonn (Germany)
- IRAM, 300 rue de la piscine, F-38406 Saint-Martin d'Hères (France)
- Cavendish Laboratory, University of Cambridge, 19 J. J. Thomson Avenue, Cambridge CB3 0HE (United Kingdom)
We present direct constraints on the CO luminosity function at high redshift and the resulting cosmic evolution of the molecular gas density, ρ{sub H{sub 2}}(z), based on a blind molecular line scan in the Hubble Deep Field North (HDF-N) using the IRAM Plateau de Bure Interferometer. Our line scan of the entire 3 mm window (79-115 GHz) covers a cosmic volume of ∼7000 Mpc{sup 3}, and redshift ranges z < 0.45, 1.01 < z < 1.89 and z > 2. We use the rich multiwavelength and spectroscopic database of the HDF-N to derive some of the best constraints on CO luminosities in high redshift galaxies to date. We combine the blind CO detections in our molecular line scan (presented in a companion paper) with stacked CO limits from galaxies with available spectroscopic redshifts (slit or mask spectroscopy from Keck and grism spectroscopy from the Hubble Space Telescope) to give first blind constraints on high-z CO luminosity functions and the cosmic evolution of the H{sub 2} mass density ρ{sub H{sub 2}}(z) out to redshifts z ∼ 3. A comparison to empirical predictions of ρ{sub H{sub 2}}(z) shows that the securely detected sources in our molecular line scan already provide significant contributions to the predicted ρ{sub H{sub 2}}(z) in the redshift bins (z) ∼ 1.5 and (z) ∼ 2.7. Accounting for galaxies with CO luminosities that are not probed by our observations results in cosmic molecular gas densities ρ{sub H{sub 2}}(z) that are higher than current predictions. We note, however, that the current uncertainties (in particular the luminosity limits, number of detections, as well as cosmic volume probed) are significant, a situation that is about to change with the emerging ALMA observatory.
- OSTI ID:
- 22351432
- Journal Information:
- Astrophysical Journal, Vol. 782, Issue 2; Other Information: Country of input: International Atomic Energy Agency (IAEA); ISSN 0004-637X
- Country of Publication:
- United States
- Language:
- English
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