The anatomy of a star-forming galaxy: pressure-driven regulation of star formation in simulated galaxies

Benincasa, Samantha M.; Wadsley, James; Couchman, H. M. P.; Keller, Ben

doi:10.1093/mnras/stw1741

Cited by 55 publications

(76 citation statements)

References 41 publications

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“…However, an increase by a factor 10 (or 100) results in a suppression by a factor of 2 (or 10) in final stellar masses. This reveals a weak, sub-linear dependence of the amount of star formation on the strength of SN feedback, compatible with results for simulated disc galaxies (Benincasa et al 2016).…”

Section: Impact Of Supernova Feedback Strengthsupporting

confidence: 88%

EDGE: the mass–metallicity relation as a critical test of galaxy formation physics

Agertz

Pontzen

Read

et al. 2019

Monthly Notices of the Royal Astronomical Society

148

177

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We introduce the "Engineering Dwarfs at Galaxy formation's Edge" (EDGE) project to study the cosmological formation and evolution of the smallest galaxies in the Universe. In this first paper, we explore the effects of resolution and sub-grid physics on a single low mass halo (M halo = 10 9 M ), simulated to redshift z = 0 at a mass and spatial resolution of ∼ 20 M and ∼ 3 pc. We consider different star formation prescriptions, supernova feedback strengths and on-the-fly radiative transfer (RT). We show that RT changes the mode of galactic self-regulation at this halo mass, suppressing star formation by causing the interstellar and circumgalactic gas to remain predominantly warm (∼ 10 4 K) even before cosmic reionisation. By contrast, without RT, star formation regulation occurs only through starbursts and their associated vigorous galactic outflows. In spite of this difference, the entire simulation suite (with the exception of models without any feedback) matches observed dwarf galaxy sizes, velocity dispersions, V-band magnitudes and dynamical mass-to-light-ratios. This is because such structural scaling relations are predominantly set by the host dark matter halo, with the remaining model-to-model variation being smaller than the observational scatter. We find that only the stellar mass-metallicity relation differentiates the galaxy formation models. Explosive feedback ejects more metals from the dwarf, leading to a lower metallicity at a fixed stellar mass. We conclude that the stellar mass-metallicity relation of the very smallest galaxies provides a unique constraint on galaxy formation physics.

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Section: Impact Of Supernova Feedback Strengthsupporting

confidence: 88%

EDGE: the mass–metallicity relation as a critical test of galaxy formation physics

Agertz

Pontzen

Read

et al. 2019

Monthly Notices of the Royal Astronomical Society

148

177

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“…In a more realistic case, the HI scale-height is time dependent and undergoes oscillation (e.g., Benincasa et al 2016). Hence, Equation 9 can be interpreted as either a static case or an average over time-scale of ∼ 100 Myrs.…”

Section: Scale Heightmentioning

confidence: 99%

The Origin of Interstellar Turbulence in M33

Utomo

Blitz

Falgarone

2019

ApJ

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We utilize the multi-wavelength data of M33 to study the origin of turbulence in its interstellar medium. We find that the HI turbulent energy surface density inside 8 kpc is ∼ 1 − 3 × 10 46 erg pc −2 , and has no strong dependence on galactocentric radius because of the lack of variation in HI surface density and HI velocity dispersion. Then, we consider the energies injected by supernovae (SNe), the magneto-rotational instability (MRI), and the gravity-driven turbulence from accreted materials as the sources of turbulent energy. For a constant dissipation time of turbulence, the SNe energy can maintain turbulence inside ∼ 4 kpc radius (equivalent to ∼ 0.5 R 25 ), while the MRI energy is always smaller than the turbulent energy within 8 kpc radius. However, when we let the dissipation time to be equal to the crossing time of turbulence across the HI scale-height, the SNe energy is enough to maintain turbulence out to 7 kpc radius, and the sum of SNe and MRI energies is able to maintain turbulence out to 8 kpc radius. Due to lack of constraint in the mass accretion rate through the disk of M33, we can not rule out the accretion driven turbulence as a possible source of energy. Furthermore, by resolving individual Giant Molecular Clouds in M33, we also show that the SNe energy can maintain turbulence within individual molecular clouds with ∼ 1% of coupling efficiency. This result strengthens the proposition that stellar feedback is an important source of energy to maintain turbulence in nearby galaxies.

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“…Recent studies show that in simulations with strong feedback, the galaxy-scale star formation rate -and hence the global depletion time -is insensitive to the local star formation efficiency (e.g., Dobbs et al 2011;Agertz et al 2013;Hopkins et al 2013aHopkins et al , 2017Agertz & Kravtsov 2015;Benincasa et al 2016;Orr et al 2017). This behavior is thought to be due to "self-regulation" of star formation by feedback (e.g., Dobbs et al 2011).…”

Section: Implications For Galaxy Formation Simulationsmentioning

confidence: 99%

“…Besides, strong feedback shapes the overall gas PDF and may increase timescales t nsf , which also results in a decrease of f sf . This happens, for example, when a gaseous disk is stabilized by a pressure corresponding to a slowly dissipating energy directly injected by feedback (e.g., Agertz et al 2013;Benincasa et al 2016).…”

Section: Implications For Galaxy Formation Simulationsmentioning

confidence: 99%

The Physical Origin of Long Gas Depletion Times in Galaxies

Semenov

Kravtsov

Gnedin

2017

ApJ

126

106

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We present a model that explains why galaxies form stars on a time scale significantly longer than the time scales of processes governing the evolution of interstellar gas. We show that gas evolves from a nonstar-forming to a star-forming state on a relatively short time scale and thus the rate of this evolution does not limit the star formation rate. Instead, the star formation rate is limited because only a small fraction of star-forming gas is converted into stars before star-forming regions are dispersed by feedback and dynamical processes. Thus, gas cycles into and out of star-forming state multiple times, which results in a long time scale on which galaxies convert gas into stars. Our model does not rely on the assumption of equilibrium and can be used to interpret trends of depletion times with the properties of observed galaxies and the parameters of star formation and feedback recipes in simulations. In particular, the model explains how feedback selfregulates the star formation rate in simulations and makes it insensitive to the local star formation efficiency. We illustrate our model using the results of an isolated L * -sized galaxy simulation that reproduces the observed Kennicutt-Schmidt relation for both molecular and atomic gas. Interestingly, the relation for molecular gas is almost linear on kiloparsec scales, although a nonlinear relation is adopted in simulation cells. We discuss how a linear relation emerges from non-self-similar scaling of the gas density PDF with the average gas surface density.

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The anatomy of a star-forming galaxy: pressure-driven regulation of star formation in simulated galaxies

Cited by 55 publications

References 41 publications

EDGE: the mass–metallicity relation as a critical test of galaxy formation physics

EDGE: the mass–metallicity relation as a critical test of galaxy formation physics

The Origin of Interstellar Turbulence in M33

The Physical Origin of Long Gas Depletion Times in Galaxies

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