How runaway stars boost galactic outflows

Andersson, Eric P.; Agertz, Oscar

doi:10.1093/mnras/staa889

Cited by 35 publications

(34 citation statements)

References 135 publications

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“…However, runaway particles that have moved far from their birth places may be in lower-density environments, with higher mass refinement, at the time of SN explosions. To some extent, the inclusion of runaways is a partial solution to numerical difficulties in resolving SNe and driving hot superbubble breakout in moderate resolution simulations like Andersson et al (2020). In our simulations, however, resolution is much higher and the majority of SNe in clusters (> 90%) resolve the Sedov-Taylor stage of evolution, so that inclusion of runaways has insignificant impact on outflows.…”

Section: Methodsmentioning

confidence: 84%

First Results from SMAUG: Characterization of Multiphase Galactic Outflows from a Suite of Local Star-forming Galactic Disk Simulations

Kim

Ostriker

Somerville

et al. 2020

ApJ

104

125

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Large scale outflows in star-forming galaxies are observed to be ubiquitous, and are a key aspect of theoretical modeling of galactic evolution in a cosmological context, the focus of the SMAUG (Simulating Multiscale Astrophysics to Understand Galaxies) project. Gas blown out from galactic disks, similar to gas within galaxies, consists of multiple phases with large contrasts of density, temperature, and other properties. To study multiphase outflows as emergent phenomena, we run a suite of ∼ pc-resolution local galactic disk simulations using the TIGRESS framework. Explicit modeling of the interstellar medium (ISM), including star formation and self-consistent radiative heating plus supernova feedback, regulates ISM properties and drives the outflow. We investigate the scaling of outflow mass, momentum, energy, and metal loading factors with galactic disk properties, including star formation rate (SFR) surface density (Σ SFR ∼ 10 −4 − 1 M kpc −2 yr −1 ), gas surface density (∼ 1 − 100 M pc −2 ), and total midplane pressure (or weight) (∼ 10 3 − 10 6 k B cm −3 K). The main components of outflowing gas are mass-delivering cool gas (T ∼ 10 4 K) and energy/metal-delivering hot gas (T ∼ 10 6 K). Cool mass outflow rates measured at outflow launch points (one or two scale heights) are 1-100 times the SFR (decreasing with Σ SFR ), although in massive galaxies most mass falls back due to insufficient outflow velocity. The hot galactic outflow carries mass comparable to 10% of the SFR, together with 10-20% of the energy and 30-60% of the metal mass injected by SN feedback. The characteristic outflow velocities of both phases scale very weakly with SFR, as v out ∝ Σ 0.1−0.2 SFR , consistent with observations. Importantly, our analysis demonstrates that in any physically-motivated cosmological wind model, it is crucial to include at least two distinct thermal wind components.

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Section: Methodsmentioning

confidence: 84%

First Results from SMAUG: Characterization of Multiphase Galactic Outflows from a Suite of Local Star-forming Galactic Disk Simulations

Kim

Ostriker

Somerville

et al. 2020

ApJ

104

125

View full text Add to dashboard Cite

show abstract

“…Furthermore, various sources of stellar feedback that would contribute to the overall formation of large-scale outflows including type Ia SNe, stellar winds, shock-accelerated cosmic rays (e.g., Uhlig et al 2012;Salem & Bryan 2014;Dashyan & Dubois 2020), multi-scattering of infrared photons with dust (e.g., Hopkins et al 2011;Roškar et al 2014;Rosdahl & Teyssier 2015), or Lyman-α resonant line scattering (Kimm et al 2018;Smith et al 2017) are neglected. In addition runaway OB stars (Ceverino & Klypin 2009;Kimm & Cen 2014;Andersson et al 2020) or the unresolved porosity of the medium (Iffrig & Hennebelle 2015) are also ignored. In this regard, the NewHorizon simulation is unlikely to overestimate the effects of stellar feedback, as described in Sect.…”

Section: Feedback From Massive Starsmentioning

confidence: 99%

Introducing the NEWHORIZON simulation: Galaxy properties with resolved internal dynamics across cosmic time

Dubois

Beckmann

Bournaud

et al. 2021

A&A

137

100

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Hydrodynamical cosmological simulations are increasing their level of realism by considering more physical processes and having greater resolution or larger statistics. However, usually either the statistical power of such simulations or the resolution reached within galaxies are sacrificed. Here, we introduce the NEWHORIZON project in which we simulate at high resolution a zoom-in region of ∼(16 Mpc)3 that is larger than a standard zoom-in region around a single halo and is embedded in a larger box. A resolution of up to 34 pc, which is typical of individual zoom-in, up-to-date resimulated halos, is reached within galaxies; this allows the simulation to capture the multi-phase nature of the interstellar medium and the clumpy nature of the star formation process in galaxies. In this introductory paper, we present several key fundamental properties of galaxies and their black holes, including the galaxy mass function, cosmic star formation rate, galactic metallicities, the Kennicutt–Schmidt relation, the stellar-to-halo mass relation, galaxy sizes, stellar kinematics and morphology, gas content within galaxies and its kinematics, and the black hole mass and spin properties over time. The various scaling relations are broadly reproduced by NEWHORIZON with some differences with the standard observables. Owing to its exquisite spatial resolution, NEWHORIZON captures the inefficient process of star formation in galaxies, which evolve over time from being more turbulent, gas rich, and star bursting at high redshift. These high-redshift galaxies are also more compact, and they are more elliptical and clumpier until the level of internal gas turbulence decays enough to allow for the formation of discs. The NEWHORIZON simulation gives access to a broad range of galaxy formation and evolution physics at low-to-intermediate stellar masses, which is a regime that will become accessible in the near future through surveys such as the LSST.

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“…Hopkins et al 2011;Roškar et al 2014;Rosdahl & Teyssier 2015) or Lyman-α resonant line scattering (Kimm et al 2018;Smith et al 2017) are neglected. In addition runaway OB stars (Ceverino & Klypin 2009;Kimm & Cen 2014;Andersson et al 2020) or the unresolved porosity of the medium (Iffrig & Hennebelle 2015) are also ignored. In this regard, the NewHorizon simulation is unlikely to over-estimate the effects of stellar feedback, as we discuss in more detail in Section 3.…”

Section: Feedback From Massive Starsmentioning

confidence: 99%

Introducing the NewHorizon simulation: Galaxy properties with resolved internal dynamics across cosmic time

Dubois,

Beckmann,

Bournaud

et al. 2020

Preprint

View full text Add to dashboard Cite

Hydrodynamical cosmological simulations are increasing their level of realism by considering more physical processes, having more resolution or larger statistics. However, one usually has to either sacrifice the statistical power of such simulations or the resolution reach within galaxies. Here, we introduce the NewHorizon project where a zoom-in region of ∼ (16 Mpc) 3 , larger than a standard zoom-in region around a single halo, embedded in a larger box is simulated at high resolution. A resolution of up to 34 pc, typical of individual zoom-in resimulated halos is reached within galaxies, allowing the simulation to capture the multi-phase nature of the interstellar medium and the clumpy nature of the star formation process in galaxies. In this introductory paper, we present several key fundamental properties of galaxies and of their black holes including the galaxy mass function, the cosmic star formation rate, the galactic metallicities, the Kennicutt-Schmidt relation, the stellar-to-halo mass relation, the galaxy sizes, their stellar kinematics and morphology, the gas content within galaxies and its kinematics, and the black hole mass and spin properties over time. The various scaling relations are broadly reproduced by NewHorizon with some differences with the standard observables. Due to its exquisite spatial resolution, NewHorizon captures the inefficient process of star formation in galaxies, which evolve over time from being more turbulent, gas-rich and star-bursting at high redshift. These high redshift galaxies are also more compact, and are more elliptical and clumpier until the level of internal gas turbulence decays enough to allow for the formation of discs. The NewHorizon simulation gives access to a broad range of galaxy physics at low-to-intermediate stellar masses, a regime that will become accessible in the near future through surveys such as the LSST.

show abstract

How runaway stars boost galactic outflows

Cited by 35 publications

References 135 publications

First Results from SMAUG: Characterization of Multiphase Galactic Outflows from a Suite of Local Star-forming Galactic Disk Simulations

First Results from SMAUG: Characterization of Multiphase Galactic Outflows from a Suite of Local Star-forming Galactic Disk Simulations

Introducing the NEWHORIZON simulation: Galaxy properties with resolved internal dynamics across cosmic time

Introducing the NewHorizon simulation: Galaxy properties with resolved internal dynamics across cosmic time

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