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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 720235.0, MPI für Astronomie / Publikationen_mpia
Combined CO and dust scaling relations of depletion time and molecular gas fractions with cosmic time, specific star-formation rate, and stellar mass
Authors:Genzel, R.; Tacconi, L. J.; Lutz, D.; Saintonge, A.; Berta, S.; Magnelli, B.; Combes, F.; García-Burillo, S.; Neri, R.; Bolatto, A.; Contini, T.; Lilly, S.; Boissier, J.; Boone, F.; Bouché, N.; Bournaud, F.; Burkert, A.; Carollo, M.; Colina, L.; Cooper, M. C.; Cox, P.; Feruglio, C.; Förster Schreiber, N. M.; Freundlich, J.; Gracia-Carpio, J.; Juneau, S.; Kovac, K.; Lippa, M.; Naab, T.; Salome, P.; Renzini, A.; Sternberg, A.; Walter, F.; Weiner, B.; Weiss, A.; Wuyts, S.
Date of Publication (YYYY-MM-DD):2015
Title of Journal:The Astrophysical Journal
Issue / Number:1
Start Page:id. 20 (25 pp)
Audience:Not Specified
Abstract / Description:We combine molecular gas masses inferred from CO emission in 500 star-forming galaxies (SFGs) between z = 0 and 3, from the IRAM-COLDGASS, PHIBSS1/2, and other surveys, with gas masses derived from Herschel far-IR dust measurements in 512 galaxy stacks over the same stellar mass/redshift range. We constrain the scaling relations of molecular gas depletion timescale (t depl) and gas to stellar mass ratio (M mol gas/M* ) of SFGs near the star formation "main-sequence" with redshift, specific star-formation rate (sSFR), and stellar mass (M* ). The CO- and dust-based scaling relations agree remarkably well. This suggests that the CO → H2 mass conversion factor varies little within ±0.6 dex of the main sequence (sSFR(ms, z, M *)), and less than 0.3 dex throughout this redshift range. This study builds on and strengthens the results of earlier work. We find that t depl scales as (1 + z)-0.3 × (sSFR/sSFR(ms, z, M *))-0.5, with little dependence on M *. The resulting steep redshift dependence of M mol gas/M * ≈ (1 + z)3 mirrors that of the sSFR and probably reflects the gas supply rate. The decreasing gas fractions at high M* are driven by the flattening of the SFR-M * relation. Throughout the probed redshift range a combination of an increasing gas fraction and a decreasing depletion timescale causes a larger sSFR at constant M *. As a result, galaxy integrated samples of the M mol gas-SFR rate relation exhibit a super-linear slope, which increases with the range of sSFR. With these new relations it is now possible to determine M mol gas with an accuracy of ±0.1 dex in relative terms, and ±0.2 dex including systematic uncertainties. Based on observations with the Plateau de Bure millimetre interferometer, operated by the Institute for Radio Astronomy in the Millimetre Range (IRAM), which is funded by a partnership of INSU/CNRS (France), MPG (Germany), and IGN (Spain).
Free Keywords:galaxies: evolution; galaxies: high-redshift; galaxies: kinematics and dynamics; infrared: galaxies
External Publication Status:published
Document Type:Article
Communicated by:N. N.
Affiliations:MPI für Astronomie
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