J/ApJ/737/L20 Metallicity dependent star formation rates (Dib, 2011)
Feedback-regulated star formation: implications for the Kennicutt-Schmidt law.
Dib S.
<Astrophys. J., 737, L20 (2011)>
=2011ApJ...737L..20D 2011ApJ...737L..20D
ADC_Keywords: Models ; Interstellar medium
Keywords: galaxies: ISM - ISM: clouds - ISM: molecules - stars: formation
Abstract:
We derive a metallicity-dependent relation between the surface density
of the star formation rate (ΣSFR) and the gas surface density
(Σg) in a feedback-regulated model of star formation in
galactic disks. In this model, star formation occurs in
gravitationally bound protocluster clumps embedded in larger giant
molecular clouds with the protocluster clump mass function following a
power-law function with a slope of -2. Metallicity-dependent feedback
is generated by the winds of OB stars (M≳5M☉) that form in the
clumps. The quenching of star formation in clumps of decreasing
metallicity occurs at later epochs due to weaker wind luminosities,
thus resulting in higher final star formation efficiencies (SFEexp).
By combining SFEexp with the timescales on which gas expulsion
occurs, we derive the metallicity-dependent SFR per unit time in this
model as a function of Σg. This is combined with the molecular
gas fraction in order to derive the global dependence of ΣSFR
on Σg. The model reproduces very well the observed star
formation laws extending from low gas surface densities up to the
starburst regime. Furthermore, our results show a dependence of
ΣSFR on metallicity over the entire range of gas surface
densities in contrast to other models and can also explain part of the
scatter in the observations. We provide a tabulated form of the star
formation laws that can easily be incorporated into numerical
simulations or semi-analytical models of galaxy formation and
evolution.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 70 276 Data for the metallicity dependent star formation
laws
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See also:
J/ApJ/723/1019 : Galactic SFR and gas surface densities (Heiderman+, 2010)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 F10.7 [Msun/pc2] logSig.g Log of gas surface density logΣgas
12- 22 E11.5 Msun/yr/kpc2 SFR0.1 Star formation rate surface density
for gas at Z=0.1 ZSun
24- 34 E11.5 Msun/yr/kpc2 SFR0.3 Star formation rate surface density
for gas at Z=0.3 ZSun
36- 46 E11.5 Msun/yr/kpc2 SFR0.5 Star formation rate surface density
for gas at Z=0.5 ZSun
48- 58 E11.5 Msun/yr/kpc2 SFR1.0 Star formation rate surface density
for gas at Z=1 ZSun
60- 70 E11.5 Msun/yr/kpc2 SFR2.0 Star formation rate surface density
for gas at Z=2 ZSun
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History:
From electronic version of the journal
(End) Greg Schwarz [AAS], Emmanuelle Perret [CDS] 10-Jan-2013