2006/06/17 by Dominik A. Riechers, Fabian Walter, Christopher L. Carilli +18 · 3 citations
Physics and Astronomy · #Astronomy #Astrophysics #Astrophysics and Star Formation Studies #Galaxies: Formation, Evolution, Phenomena #Galaxy #Green Bank Telescope #Line (geometry) #Luminosity #Physics #QSOS #Quasar #Redshift #Stellar, planetary, and galactic studies #Telescope #astro-ph
paper · pdf · doi:10.1086/507014
published as Astrophys.J.650:604-613,2006 · 12 pages, 5 figures, 3 tables, to appear in ApJ (accepted June 16, 2006)
arxiv created 2006/06/17 · openalex publication_date 2006/10/18 · arxiv updated 2009/12/01 · openalex created_date 2019/12/26 · openalex updated_date 2026/08/05
We present 12 CO( J = 1 → 0) observations of the high-redshift quasi-stellar objects (QSOs) BR 1202-0725 ( z = 4.69), PSS J2322+1944 ( z = 4.12), and APM 08279+5255 ( z = 3.91) using the NRAO Green Bank Telescope (GBT) and the MPIfR Effelsberg 100 m telescope. We detect, for the first time, the CO ground-level transition in BR 1202-0725. For PSS J2322+1944 and APM 08279+5255, our observations result in line fluxes that are consistent with previous NRAO Very Large Array (VLA) observations, but they reveal the full line profiles. We report a typical lensing-corrected velocity-integrated intrinsic 12 CO( J = 1 → 0) line luminosity of L = 5 × 10 10 K km s -1 pc 2 and a typical total H 2 mass of M (H 2 ) = 4 × 10 10 M ☉ for the sources in our sample. The CO/FIR luminosity ratios of these high- z sources follow the same trend as seen for low- z galaxies, leading to a combined solution of log L FIR = (1.39 ± 0.05) log L CO - 1.76. It has previously been suggested that the molecular gas reservoirs in some quasar host galaxies may exhibit luminous, extended 12 CO( J = 1 → 0) components that are not observed in the higher J CO transitions. Using the line profiles and the total intensities of our observations and large velocity gradient (LVG) models based on previous results for higher J CO transitions, we derive that emission from all CO transitions is described well by a single gas component in which all molecular gas is concentrated in a compact nuclear region. Thus, our observations and models show no indication of a luminous extended, low surface brightness molecular gas component in any of the high-redshift QSOs in our sample. If such extended components exist, their contribution to the overall luminosity is limited to at most 30%.