Star formation at low rates - the impact of lacking massive stars on stellar feedback

Hensler, G.; Steyrleithner, Patrick; Recchi, Simone

doi:10.1017/s1743921316011261

Cited by 2 publications

(1 citation statement)

References 14 publications

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“…They further found that regardless of sampling method, the combined IMF of multiple star particles together will be undersampled below particle masses of ∼10 3 M . Bracketing the case of a stochastic IMF, Hensler et al (2017) compared a truncated and a filled IMF in simulations of dwarf galaxies, and found that truncation suppresses the self-regulation of star formation. Several cosmological simulations have discussed or incorporated methods of discretizing stellar feedback from Type II supernovae (e.g.…”

Section: Introductionmentioning

confidence: 99%

A stochastically sampled IMF alters the stellar content of simulated dwarf galaxies

Applebaum

Brooks

Quinn

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Cosmological simulations are reaching the resolution necessary to study ultra-faint dwarf galaxies. Observations indicate that in small populations, the stellar initial mass function (IMF) is not fully populated; rather, stars are sampled in a way that can be approximated as coming from an underlying probability density function. To ensure the accuracy of cosmological simulations in the ultra-faint regime, we present an improved treatment of the IMF. For the first time, we implement a self-consistent, stochastically populated IMF in cosmological hydrodynamic simulations. We test our method using high-resolution simulations of a Milky Way halo, run to z = 6, yielding a sample of nearly 100 galaxies. We also use an isolated dwarf galaxy to investigate the resulting systematic differences in galaxy properties. We find that a stochastic IMF in simulations makes feedback burstier, strengthening feedback, and quenching star formation earlier in small dwarf galaxies. For galaxies in halos with mass 10 8.5 M , a stochastic IMF typically leads to lower stellar mass compared to a continuous IMF, sometimes by more than an order of magnitude. We show that existing methods of ensuring discrete supernovae incorrectly determine the mass of the star particle and its associated feedback. This leads to overcooling of surrounding gas, with at least ∼10 per cent higher star formation and ∼30 per cent higher cold gas content. Going forward, to accurately model dwarf galaxies and compare to observations, it will be necessary to incorporate a stochastically populated IMF that samples the full spectrum of stellar masses.With the recent successes in modeling dwarf galaxies, various groups are pushing the limits of resolution even further, into the ultra-faint dwarf (UFD) galaxy range (M star 10 5 M ; e.g.

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Section: Introductionmentioning

confidence: 99%

A stochastically sampled IMF alters the stellar content of simulated dwarf galaxies

Applebaum

Brooks

Quinn

et al. 2019

Monthly Notices of the Royal Astronomical Society

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The effect of ram-pressure stripping on dwarf galaxies

Steyrleithner

Hensler

Boselli

2020

Monthly Notices of the Royal Astronomical Society

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Ram-pressure stripping (RPS) is a well observed phenomenon of massive spiral galaxies passing through the hot intra-cluster medium (ICM) of galaxy clusters. For dwarf galaxies (DGs) within a cluster, the transformation from gaseous to gas-poor systems by RPS is not easily observed and must happen in the outskirts of clusters. In a few objects in close by galaxy clusters and the field, RPS has been observed. Since cluster early-type DGs also show a large variety of internal structures (unexpected central gas reservoirs, blue stellar cores, composite radial stellar profiles), we aim in this study to investigate how ram pressure (RP) affects the interstellar gas content and therefore the star-formation (SF) activity. Using a series of numerical simulations, we quantify the dependence of the stripped-off gas on the velocity of the infalling DGs and on the ambient ICM density. We demonstrated that SF can be either suppressed or triggered by RP depending on the ICM density and the DGs mass. Under some conditions, RP can compress the gas, so that it is unexpectedly retained in the central DG region and forms stars. When gas clouds are still bound against stripping but lifted from a thin disk and fall back, their new stars form an ellipsoidal (young) stellar population already with a larger velocity dispersion without the necessity of harassment. Most spectacularly, star clusters can form downstream in stripped-off massive gas clouds in the case of strong RP. We compare our results to observations.

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Star formation at low rates - the impact of lacking massive stars on stellar feedback

Cited by 2 publications

References 14 publications

A stochastically sampled IMF alters the stellar content of simulated dwarf galaxies

A stochastically sampled IMF alters the stellar content of simulated dwarf galaxies

The effect of ram-pressure stripping on dwarf galaxies

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