Astronomy and Astrophysics – Astrophysics – Cosmology and Extragalactic Astrophysics
Scientific paper
2010-07-21
Mon. Not. Roy. Astron. Soc. 417:2962-2981, 2011
Astronomy and Astrophysics
Astrophysics
Cosmology and Extragalactic Astrophysics
MNRAS, in press; 22 pages, 13 figures. Several structural changes, including a new section on varying the IMF (yield)
Scientific paper
10.1111/j.1365-2966.2011.19456.x
We extend a chemical evolution model relating galaxy stellar mass and gas-phase oxygen abundance (the mass-metallicity relation) to explicitly consider the mass-dependence of galaxy gas fractions and outflows. Using empirically derived scalings of galaxy mass with halo virial velocity in conjunction with the most recent observations of z~0 total galaxy cold gas fractions and the mass-metallicity relation, we place stringent global constraints on the magnitude and scaling of the efficiency with which star forming galaxies expel metals. We demonstrate that under the assumptions that metal accretion is negligible and the stellar initial mass function does not vary, efficient outflows are required to reproduce the mass-metallicity relation; without winds, gas-to-stellar mass ratios >~ 0.3 dex higher than observed are needed. Moreover, z=0 gas fractions are low enough that while they have some effect on the magnitude of outflows required, the slope of the gas fraction--stellar mass relation does not strongly affect our conclusions on how the wind efficiencies must scale with galaxy mass. Despite systematic uncertainties in the normalization and slope of the mass-metallicity relation, we show that the metal expulsion efficiency zetaw=(Zw/Zg)etaw (where Zw is the wind metallicitiy and Zg is the interstellar medium metallicity) must be both high and scale steeply with mass. Specifically, we show that zetaw >> 1 and zetaw proportional to vvir^-3 or steeper. In contrast, momentum- or energy-driven outflow models suggest that etaw should scale as vvir^-1 or vvir^-2, respectively, implying that the Zw-Mstar relation should be shallower than the Zg-Mstar relation. [abridged]
Peeples Molly S.
Shankar Francesco
No associations
LandOfFree
Constraints on star-formation driven galaxy winds from the mass-metallicity relation at z=0 does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Constraints on star-formation driven galaxy winds from the mass-metallicity relation at z=0, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Constraints on star-formation driven galaxy winds from the mass-metallicity relation at z=0 will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-610034