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          Institute: MPI für Astronomie     Collection: Publikationen_mpia     Display Documents

ID: 447967.1, MPI für Astronomie / Publikationen_mpia
The star formation law on sub-kpc resolution in THINGS
Authors:Bigiel, F.; Walter, F.; Leroy, A.; Brinks, E.; de Blok, W. J. G.; Madore, B.; Thornley, M. D.
Date of Publication (YYYY-MM-DD):2009-01
Title of Proceedings:The Evolving ISM in the Milky Way and Nearby Galaxies
Start Page:12
Physical Description:online only
Review Status:not specified
Audience:Experts Only
Abstract / Description:We present results from a comprehensive analysis of the relation between HI, H_2, total gas (HI+H_2) and star formation rate surface density (SigmaHI, SigmaH2, Sigmagas and SigmaSFR respectively) in 18 nearby galaxies (7 spirals and 11 HI-dominated dwarfs) at 750 pc resolution. We use high resolution HI data from THINGS, CO data from IRAM and BIMA, 24 mum data from the Spitzer Space Telescope, and UV data from GALEX. We find that a Schmidt-type power law with index N=1.0 ± 0.2 relates SigmaSFR and SigmaH2 across our sample of spiral galaxies, i.e. that H_2 forms stars at a constant efficiency in spirals with an average molecular gas depletion time of Ëœ 2 \cdot 10^9 years. We interpret the linear relation and constant depletion time as evidence that stars are forming in GMCs with approximately uniform properties and that SigmaH2 may be more a measure of the filling fraction of giant molecular clouds than changing conditions in the molecular gas. We find no correlation between SigmaHI and SigmaSFR. The dwarf galaxies in our sample resemble the outer disks of spirals in SigmaSFR-Sigmagas space. This is likely due to the similarity of both environments (low,density, low,metallicity, HI,dominated). We furthermore find a sharp saturation of SigmaHI at Ëœ9 Mo pc-2 in both the spiral and the dwarf galaxies. For the spirals, we observe gas in excess of this cutoff to be molecular.
Free Keywords:radio lines: galaxies; radio lines: ISM; galaxies: ISM; galaxies: evolution
Comment of the Author/Creator:Date: 2009 online, January 1, 2009
External Publication Status:published
Document Type:Conference-Paper
Communicated by:N. N.
Affiliations:MPI für Astronomie
Identifiers:URL:http://adsabs.harvard.edu/abs/2009eimw.confE..12B [ID No:1]
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