Hot phase generation by supernovae in ISM simulations: resolution, chemistry, and thermal conduction

Steinwandel, Ulrich P.; Moster, Benjamin P.; Naab, Thorsten; Hu, Chia-Yu; Walch, Stefanie

doi:10.1093/mnras/staa821

Cited by 47 publications

(55 citation statements)

References 101 publications

(166 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Changing the shape of the IMF from Salpeter to Chabrier slightly alters star-formation-related quantities (in agreement with e.g. Cassarà et al 2013), while varying wind velocities (Hassan & Gronke 2021) or SN efficiency has an impact of up to 1 dex when these parameters are varied by a factor of 5-10, independently of other model assumptions (Steinwandel et al 2020). For HI, the impact is less dramatic and results vary by less than 0.5 dex.…”

Section: Discussionsupporting

confidence: 60%

Atomic and molecular gas from the epoch of reionisation down to redshift 2

Maio

Péroux

Ciardi

2022

A&A

View full text Add to dashboard Cite

Context. Cosmic gas makes up about 90% of the baryonic matter in the Universe and H2 molecule is the most tightly linked to star formation. Aims. In this work we study cold neutral gas, its H2 component at different epochs, and corresponding depletion times. Methods. We perform state-of-the-art hydrodynamic simulations that include time-dependent atomic and molecular non-equilibrium chemistry coupled to star formation, feedback effects, different UV backgrounds presented in the recent literature and a number of additional processes occurring during structure formation (COLDSIM). We predict gas evolution and contrast the mass density parameters and gas depletion timescales. We also investigate their relation to cosmic expansion in light of the latest infrared and (sub)millimetre observations in the redshift range 2 ≲ z ≲ 7. Results. By performing updated non-equilibrium chemistry calculations we are able to broadly reproduce the latest HI and H2 observations. We find neutral-gas mass density parameters Ωneutral ≃ 10−3 and increasing from lower to higher redshift, in agreement with available HI data. Because of the typically low metallicities during the epoch of reionisation, time-dependent H2 formation is mainly led by the H− channel in self-shielded gas, while H2 grain catalysis becomes important in locally enriched sites at any redshift. Ultraviolet (UV) radiation provides free electrons and facilitates H2 build-up while heating cold metal-poor environments. Resulting H2 fractions can be as high as ∼50% of the cold gas mass at z ∼ 4–8, in line with the latest measurements from high-redshift galaxies. The H2 mass density parameter increases with time until a plateau of ΩH2 ≃ 10−4 is reached. Quantitatively, we find agreement between the derived ΩH2 values and the observations up to z ∼ 7 and both HI and H2 trends are better reproduced by our non-equilibrium H2-based star formation modelling. The predicted gas depletion timescales decrease at lower z in the whole time interval considered, with H2 depletion times remaining below the Hubble time and comparable to the dynamical time at all z. This implies that non-equilibrium molecular cooling is efficient at driving cold-gas collapse in a broad variety of environments and has done so since very early cosmic epochs. While the evolution of chemical species is clearly affected by the details of the UV background and gas self shielding, the assumptions on the adopted initial mass function, different parameterizations of H2 dust grain catalysis, photoelectric heating, and cosmic-ray heating can affect the results in a non-trivial way. In the Appendix, we show detailed analyses of individual processes, as well as simple numerical parameterizations and fits to account for them. Conclusions. Our findings suggest that, in addition to HI, non-equilibrium H2 observations are pivotal probes for assessing cold-gas cosmic abundances and the role of UV background radiation at different epochs.

show abstract

Section: Discussionsupporting

confidence: 60%

Atomic and molecular gas from the epoch of reionisation down to redshift 2

Maio

Péroux

Ciardi

2022

A&A

View full text Add to dashboard Cite

show abstract

“…In cases where the SN remnant is resolved, the FIRE-2 subgrid model explicitly deposits the thermal energy expected from the energy-conserving phase, and allows the hydrodynamic solver to explicitly calculate the heating and momentum generation (𝑃𝑑𝑉 work). Note that while some small-scale simulations suggest that a resolution of < ∼ 100𝑀 may be necessary to properly capture the evolution of SN remnants (e.g., Kim & Ostriker 2015;Steinwandel et al 2020), the combination of multiple stellar feedback effects (e.g., early radiative feedback) with self-consistent clustering of star formation in FIRE-2 may act to alleviate this resolution requirement. Hopkins et al (2018a, Figure 9) showed that the FIRE subgrid model remains converged to the high-resolution result up to resolutions of 2000𝑀 for an m10 halo (see also Wheeler et al 2019, who re-simulated a few FIRE-2 dwarfs with 30𝑀 resolution).…”

Section: Simulation Descriptionmentioning

confidence: 99%

Characterizing mass, momentum, energy, and metal outflow rates of multiphase galactic winds in the FIRE-2 cosmological simulations

Pandya

Fielding

Anglés-Alcázar

et al. 2021

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We characterize mass, momentum, energy and metal outflow rates of multi-phase galactic winds in a suite of FIRE-2 cosmological ‘zoom-in’ simulations from the Feedback in Realistic Environments (FIRE) project. We analyse simulations of low-mass dwarfs, intermediate-mass dwarfs, Milky Way-mass haloes, and high-redshift massive haloes. Consistent with previous work, we find that dwarfs eject about 100 times more gas from their interstellar medium (ISM) than they form in stars, while this mass ‘loading factor’ drops below one in massive galaxies. Most of the mass is carried by the hot phase (>105 K) in massive haloes and the warm phase (103 − 105 K) in dwarfs; cold outflows (<103 K) are negligible except in high-redshift dwarfs. Energy, momentum and metal loading factors from the ISM are of order unity in dwarfs and significantly lower in more massive haloes. Hot outflows have 2 − 5 × higher specific energy than needed to escape from the gravitational potential of dwarf haloes; indeed, in dwarfs, the mass, momentum, and metal outflow rates increase with radius whereas energy is roughly conserved, indicating swept up halo gas. Burst-averaged mass loading factors tend to be larger during more powerful star formation episodes and when the inner halo is not virialized, but we see effectively no trend with the dense ISM gas fraction. We discuss how our results can guide future controlled numerical experiments that aim to elucidate the key parameters governing galactic winds and the resulting associated preventative feedback.

show abstract

“…In order to launch strong outflows, the SFI has to be high enough, so that overlapping SN explosions create a volume-filling hot phase such that gas is removed in a thermally driven outflow. In the Milky Way and at the present epoch, the SFI is too low and disfavour the build-up of overlapping hot bubbles and the formation of strong outflows (Gatto et al 2015;L ie ta l .2015;Naab & Ostriker 2017;Steinwandel et al 2020). This has been demonstrated for example byKim&Ostriker(2015), Walch et al (2015), and Girichidis et al (2016) using high-resolution simulations of stratified galactic discs with multiple SN explosions.…”

Section: The Emergence Of Quiescent Discsmentioning

confidence: 85%

Rapid filamentary accretion as the origin of extended thin discs

Kretschmer

Agertz

Teyssier

2020

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Galactic outflows driven by stellar feedback are crucial for explaining the inefficiency of star formation in galaxies. Although strong feedback can promote the formation of galactic discs by limiting star formation at early times and removing low angular momentum gas, it is not understood how the same feedback can result in diverse objects such as elliptical galaxies or razor thin spiral galaxies. We investigate this problem using cosmological zoom-in simulations of two galaxies forming within 1012 M⊙ halos with almost identical mass accretion histories and halo spin parameters. However, the two resulting galaxies end up with very different bulge-to-disc ratios at z = 0. At z > 1.5, the two galaxies feature a surface density of star formation ΣSFR ≃ 10 M⊙ yr−1 kpc−2, leading to strong outflows. After the last starburst episode, both galaxies feature a dramatic gaseous disc growth from 1 kpc to 5 kpc during 1 Gyr, a decisive event we dub “the Grand Twirl”. After this event, the evolutionary tracks diverge strongly, with one galaxy ending up as a bulge-dominated galaxy, whereas the other ends up as a disc-dominated galaxy. The origins of this dichotomy are the angular momentum of the accreted gas, and whether it adds constructively to the initial disc angular momentum. The build-up of this extended disc leads to a rapid lowering of ΣSFR by over two orders of magnitude with ΣSFR ≲ 0.1 M⊙ yr−1 kpc−2, in remarkable agreement with what is derived from Milky Way stellar populations. As a consequence, supernovae explosions are spread out and cannot launch galactic outflows anymore, allowing for the persistence of a thin, gently star forming, extended disc.

show abstract

Hot phase generation by supernovae in ISM simulations: resolution, chemistry, and thermal conduction

Cited by 47 publications

References 101 publications

Atomic and molecular gas from the epoch of reionisation down to redshift 2

Atomic and molecular gas from the epoch of reionisation down to redshift 2

Characterizing mass, momentum, energy, and metal outflow rates of multiphase galactic winds in the FIRE-2 cosmological simulations

Rapid filamentary accretion as the origin of extended thin discs

Contact Info

Product

Resources

About