J/A+A/627/A131 GAS I. Stellar mass functions (Cousin+, 2019)
G.A.S. I. A prescription for turbulence-regulated star formation and its
impact on galaxy properties.
Cousin M., Guillard P., Lehnert M.D.
<Astron. Astrophys. 627, A131 (2019)>
=2019A&A...627A.131C 2019A&A...627A.131C (SIMBAD/NED BibCode)
ADC_Keywords: Models ; Galaxies
Keywords: galaxies: formation - galaxies: evolution - galaxies: star formation -
galaxies: ISM - methods: numerical
Abstract:
Star formation in galaxies is inefficient, and understanding how star
formation is regulated in galaxies is one of the most fundamental
challenges of contemporary astrophysics. Radiative cooling, feedback
from supernovae and active galactic nuclei, largescale dynamics and
dissipation of turbulent energy act over various time and spatial
scales, and all regulate star formation in a complex gas cycle.
This paper presents the physics implemented in a new semi-analytical
model of galaxy formation and evolution: G.A.S. .
The fundamental underpinning of our new model is the development of a
multi-phase interstellar medium (ISM) in which energy produced by
supernovae and active galaxy nuclei maintains an equilibrium between
the diffuse, hot, stable gas and a cooler, clumpy, low-volume filling
factor gas. The hot gas is susceptible to thermal and dynamical
instabilities. We include a description of how turbulence leads to the
formation of giant molecular clouds through an inertial turbulent
energy cascade, assuming a constant kinetic energy transfer per unit
volume. We explicitly model the evolution of the velocity dispersion
at different scales of the cascade and account for thermal
instabilities in the hot halo gas. Thermal instabilities effectively
reduces the impact of radiative cooling and moderates accretion rates
onto galaxies, and in particular, for those residing in massive halos.
We show that rapid and multiple exchanges between diffuse and unstable
gas phases strongly regulates star-formation rates in galaxies because
only a small fraction of the unstable gas is forming stars. We checked
that the characteristic timescales describing the gas cycle, the gas
depletion timescale and the star-forming laws at different scales are
in good agreement with observations. For high mass halos and galaxies,
cooling is naturally regulated by the growth of thermal instabilities,
so we do not need to implement strong AGN feedback in this model. Our
results are also in good agreement with the observed stellar mass
function from z~=6.0 to z~=0.5.
Our model offers the flexibility to test the impact of various
physical processes on the regulation of star formation on a
representative population of galaxies across cosmic times. Thermal
instabilities and the cascade of turbulent energy in the dense gas
phase introduce a delay between gas accretion and star formation,
which keeps galaxy growth inefficient in the early Universe. The main
results presented in this paper, such as stellar mass functions, are
available in the GALAKSIENN library.
Description:
We present a new semi-analytical model, G.A.S., in which we
implemented a more realistic gas cycle than has been previously
implemented in a semi-analytical model.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
smf.dat 130 18 Stellar mass functions predicted by the
G.A.S. model
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See also:
J/A+A/627/A132 : GAS II. UV luminosity functions & InfraRed eXcess
(Cousin+, 2019)
https://zenodo.org/record/1451229#.XIJp24XjIeM : ALL G.A.S. data
Byte-by-byte Description of file: smf.dat
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Bytes Format Units Label Explanations
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1- 6 F6.3 [Msun] logM* Stellar mass
10- 18 E9.4 Mpc-3 CD0.14 Comoving density at z=0.14 (in gal/dex/Mpc3 unit)
24- 32 E9.4 Mpc-3 CD0.35 Comoving density at z=0.35 (in gal/dex/Mpc3 unit)
38- 46 E9.4 Mpc-3 CD0.64 Comoving density at z=0.64 (in gal/dex/Mpc3 unit)
52- 60 E9.4 Mpc-3 CD1.08 Comoving density at z=1.08 (in gal/dex/Mpc3 unit)
66- 74 E9.4 Mpc-3 CD2.07 Comoving density at z=2.07 (in gal/dex/Mpc3 unit)
80- 88 E9.4 Mpc-3 CD2.84 Comoving density at z=2.84 (in gal/dex/Mpc3 unit)
94-102 E9.4 Mpc-3 CD3.99 Comoving density at z=3.99 (in gal/dex/Mpc3 unit)
108-116 E9.4 Mpc-3 CD4.75 Comoving density at z=4.75 (in gal/dex/Mpc3 unit)
122-130 E9.4 Mpc-3 CD5.87 Comoving density at z=5.87 (in gal/dex/Mpc3 unit)
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History:
Copied at https://zenodo.org/
References:
Cousins et al., Paper II 2019A&A...627A.132C 2019A&A...627A.132C
(End) Patricia Vannier [CDS] 08-Mar-2019