Toward a Complete Accounting of Energy and Momentum From Stellar Feedback in Galaxy Formation Simulations

Agertz, Oscar; Kravtsov, Andrey V.; Leitner, Samuel N.; Gnedin, Nickolay Y.

doi:10.1088/0004-637x/770/1/25

Cited by 488 publications

(675 citation statements)

References 137 publications

(183 reference statements)

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“…This ionizing radiation injects momentum in the cells neighbouring massive star particles younger than 5 Myr, and whose column density exceeds 10 21 cm −2 , isotropically pressurizing the star-forming regions (as described also in Agertz et al (2013)). …”

Section: Zoom-in Cosmological Simulationsmentioning

confidence: 93%

Evolution of galaxy shapes from prolate to oblate through compaction events

Tomassetti

Dekel²,

Mandelker³

et al. 2016

Mon. Not. R. Astron. Soc.

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We study the evolution of global shapes of galaxies using cosmological simulations. The shapes refer to the components of dark matter (DM), stars and gas at the stellar half-mass radius. Most galaxies undergo a characteristic compaction event into a blue nugget at z ∼ 2 − 4, which marks the transition from a DM-dominated central body to a self-gravitating baryonic core. We find that in the high-z, DM-dominated phase, the stellar and DM systems tend to be triaxial, preferentially prolate and mutually aligned. The elongation is supported by an anisotropic velocity dispersion that originates from the assembly of the galaxy along a dominant large-scale filament. We estimate that torques by the dominant halo are capable of inducing the elongation of the stellar system and its alignment with the halo. Then, in association with the transition to self-gravity, small-pericenter orbits puff up and the DM and stellar systems evolve into a more spherical and oblate configuration, aligned with the gas disc and associated with rotation. This transition typically occurs when the stellar mass is ∼ 10 9 M and the escape velocity in the core is ∼ 100 km s −1 , indicating that supernova feedback may be effective in keeping the core DM-dominated and the system prolate. The early elongated phase itself may be responsible for the compaction event, and the transition to the oblate phase may be associated with the subsequent quenching in the core.

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Section: Zoom-in Cosmological Simulationsmentioning

confidence: 93%

Evolution of galaxy shapes from prolate to oblate through compaction events

Tomassetti

Dekel²,

Mandelker³

et al. 2016

Mon. Not. R. Astron. Soc.

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“…25, we have plotted KS diagrams for simulations without feedback and with a feedback efficiency α fb = 10%. These can be compared to Agertz et al (2013)'s plots of azimuthally averaged KS diagrams of disc galaxies for different feedback intensities. Very similarly, we observe a global diminution of the SFR surface density when we increase the feedback strength.…”

Section: Star Formationmentioning

confidence: 99%

Influence of baryonic physics in galaxy simulations:

Halle¹,

Combes²

2013

A&A

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Recent work in galaxy formation has enlightened the important role of baryonic physics to solve the main problems encountered by the standard theory at the galactic scale, such as the galaxy stellar mass function or the problem of missing satellites. The present work aims at investigating the role of the cold and dense molecular phase, which could be a gas reservoir in the outer galaxy discs, with low star-formation efficiency. By using hydrodynamical simulations, implementing the cooling to low temperatures, and including the molecular hydrogen component, several feedback efficiencies are studied, and results on the gas morphology and star formation are obtained. It is shown that molecular hydrogen allows some slow star formation (with gas depletion times of ∼5 Gyr) to occur in the outer parts of the discs. This dense and quiescent phase might be a way to store a significant fraction of dark baryons in a relatively long timescale in the complete baryonic cycle that connects the galaxy discs to hot gaseous haloes and to the cosmic filaments.

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“…We adopt the initial conditions that were used in the AGORA code comparison project (Kim et al 2016) and also in the studies of Agertz et al (2013) and Semenov et al (2016). Specifically, the isolated disk is initialized inside a dark matter halo with v c,200 = 150 km s −1 and an initial concentration of c = 10.…”

Section: Introductionmentioning

confidence: 99%

The Physical Origin of Long Gas Depletion Times in Galaxies

Semenov

Kravtsov

Gnedin

2017

ApJ

Self Cite

124

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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Toward a Complete Accounting of Energy and Momentum From Stellar Feedback in Galaxy Formation Simulations

Cited by 488 publications

References 137 publications

Evolution of galaxy shapes from prolate to oblate through compaction events

Evolution of galaxy shapes from prolate to oblate through compaction events

Influence of baryonic physics in galaxy simulations:

The Physical Origin of Long Gas Depletion Times in Galaxies

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