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Persistent URL http://purl.org/net/epubs/work/10919495
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Record Id 10919495
Title Goods-Herschel: Gas-to-dust mass ratios and CO-TO-H conversion factors in normal and starbursting galaxies at high-z
Abstract We explore the gas-to-dust mass ratio (M /M ) and the CO luminosity-to-M conversion factor (?) of two well-studied galaxies in the Great Observatories Origins Deep Survey North field that are expected to have different star-forming modes, the starburst GN20 at z = 4.05 and the normal star-forming galaxy BzK-21000 at z = 1.52. Detailed sampling is available for their Rayleigh-Jeans emission via ground-based millimeter (mm) interferometry (1.1-6.6mm) along with Herschel PACS and SPIRE data that probe the peak of their infrared emission. Using the physically motivated Draine \\& Li models, as well as a modified blackbody function, we measure the dust mass (M ) of the sources and find (2.0 × 10) M for GN20 and (8.6 × 10) M for BzK-21000. The addition of mm data reduces the uncertainties of the derived M by a factor of ?2, allowing the use of the local M /M versus metallicity relation to place constraints on the ? values of the two sources. For GN20 we derive a conversion factor of ? < 1.0 M pc(Kkms), consistent with that of local ultra-luminous infrared galaxies, while for BzK-21000 we find a considerably higher value, ? ?4.0 M pc(Kkms), in agreement with an independent kinematic derivation reported previously. The implied star formation efficiency is ?25 L /M for BzK-21000, a factor of ?5-10 lower than that of GN20. The findings for these two sources support the existence of different disk-like and starburst star formation modes in distant galaxies, although a larger sample is required to draw statistically robust results. © 2011. The American Astronomical Society. All rights reserved.
Organisation STFC , RALSP , RALSP - SPD
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Language English (EN)
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Journal Article Astrophysical Journal Letters 740 (2011): L15. doi:10.1088/2041-8205/740/1/L15 2011