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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 358854.1, MPI für Astronomie / Publikationen_mpia
CO(1--0) emission from quasar host galaxies beyond redshift 4
Authors:Riechers, D. A.; Walter, F.; Carilli, C. L.; Knudsen, K. K.; Lo, K. Y.; Benford, D. J.; Staguhn, J. G.; Hunter, T. R.; Bertoldi, F.; Henkel, C.; Menten, K. M.; Weiss, A.; Yun, M. S.; Scoville, N. Z.
Place of Publication:San Francisco
Date of Publication (YYYY-MM-DD):2007
Title of Proceedings:From Z-Machines to ALMA: (Sub)Millimeter Spectroscopy of Galaxies
Start Page:148
End Page:156
Title of Series:ASP Conf. Ser.
Volume (in Series):375
Review Status:not specified
Audience:Experts Only
Abstract / Description:Molecular gas has now been detected in 15 z > 2 QSOs through observations of high-J CO transitions using millimeter interferometers. Observations of the CO ground-state transition CO(1--0), however, have the potential to trace the molecular gas at lower excitations, which may give a better estimate of the total molecular gas content of high-z QSOs. Here we present the first z > 4 CO(1--0) observations obtained with the NRAO Green Bank Telescope (GBT) and the MPIfR Effelsberg telescope. Utilizing the K band receivers of these two 100 m radio telescopes, we detect the CO(1--0) transition in the high-redshift QSOs BR1202-0725 (z=4.7), PSS J2322+1944 (z=4.1), and APM08279+5255 (z=3.9). From LVG models based on our observations out to z = 4.7, we derive that the CO emission from all observed transitions can be described by a single gas component, and that all molecular gas appears to be concentrated in a compact nuclear region. The spectral capabilities of the GBT (1 × 200 MHz in high-resolution mode, 2 × 800 MHz in high-bandwidth mode) allow us to cover velocity ranges of up to 22,000 km s-1, or Delta z/z = 0.09 at z = 4, which will be imperative for future high-z studies in galaxies with known strong dust continuum but poorly constrained redshift. This is a first step towards observations with future z-machines.
External Publication Status:published
Document Type:Conference-Paper
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:URL:http://adsabs.harvard.edu/abs/2007ASPC..375..148R [ID No:1]
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