Self-regulation models for star formation

2007 ◽  
pp. 250-259
Author(s):  
Joseph Silk
Keyword(s):  
Star Formation ◽  
Self Regulation

scholarly journals The Galactic Ecosystem

2004 ◽  
Vol 213 ◽  
pp. 123-126
Author(s):  
Michael Burton
Keyword(s):  
Star Formation ◽  
Crucial Role ◽  
Self Regulation ◽  
Spiral Arms ◽  
Carbon Abundance

We discuss how the process of star formation across the spiral arms of galaxies functions as an ecosystem. The carbon abundance plays a crucial role in both its self-regulation and evolution.

Star formation at low rates: impact of lacking massive stars on the evolution of dwarf galaxies

2018 ◽  
Vol 14 (S344) ◽  
pp. 186-189
Author(s):  
P. Steyrleithner ◽  
G. Hensler ◽  
S. Recchi ◽  
S. Ploeckinger
Keyword(s):  
Star Formation ◽  
Numerical Simulations ◽  
Galaxy Evolution ◽  
Dwarf Galaxies ◽  
Massive Stars ◽  
Self Regulation ◽  
Mass Function ◽  
Initial Mass Function ◽  
Single Star ◽  
The Imf

AbstractIn recent years dedicated observations have uncovered star formation at extremely low rates in dwarf galaxies, tidal tails, ram-pressure stripped gas clouds, and the outskirts of galactic disks. At the same time, numerical simulations of galaxy evolution have advanced to higher spatial and mass resolutions, but have yet to account for the underfilling of the uppermost mass bins of stellar initial mass function (IMF) at low star-formation rates. In such situations, simulations may simply scale down the IMF, without realizing that this unrealistically results in fractions of massive stars, along with fractions of massive star feedback energy (e.g., radiation and SNII explosions). Not properly accounting for such parameters has consequences for the self-regulation of star formation, the energetics of galaxies, as well as for the evolution of chemical abundances. Here we present numerical simulations of dwarf galaxies with low star-formation rates allowing for two extreme cases of the IMF: a “filled” case with fractional massive stars vs. a truncated IMF, at which the IMF is built bottom-up until the gas reservoir allows the formation of a last single star at an uppermost mass. The aim of the study is to demonstrate the different effects on galaxy evolution with respect to self-regulation, feedback, and chemistry. The case of a stochastic sampled IMF is situated somewhere in between these extremes.

scholarly journals The EDGE-CALIFA survey: Self-regulation of Star formation at kpc scales

2021 ◽  
Author(s):  
J K Barrera-Ballesteros ◽  
S F Sánchez ◽  
T Heckman ◽  
T Wong ◽  
A Bolatto ◽  
...  
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
Self Regulation ◽  
Stellar Mass ◽  
Good Representation ◽  
Star Forming ◽  
Star Forming Regions ◽  
Wide Range ◽  
Two Parameters ◽  
Stellar Masses

Abstract The processes that regulate star formation are essential to understand how galaxies evolve. We present the relation between star formation rate density, ΣSFR , and hydrostatic midplane pressure, Ph , for 4260 star-forming regions of kpc size located in 96 galaxies included in the EDGE-CALIFA survey covering a wide range of stellar masses and morphologies. We find that these two parameters are tightly correlated, showing a smaller scatter in comparison to other star-forming relations. A power-law, with a slightly sub-linear index, is a good representation of this relation. Its residuals show a significant anti-correlation with both stellar age and metallicity whereas the total stellar mass may also play a secondary role in shaping the ΣSFR - Ph relation. For actively star-forming regions we find that the effective feedback momentum per unit stellar mass (p*/m*), measured from the Ph/ΣSFR ratio increases with Ph. The median value of this ratio for all the sampled regions is larger than the expected momentum just from supernovae explosions. Morphology of the galaxies, including bars, does not seem to have a significant impact in the ΣSFR - Ph relation. Our analysis indicates that local ΣSFR self-regulation comes mainly from momentum injection to the interstellar medium from supernovae explosions. However, other mechanisms in disk galaxies may also play a significant role in shaping the ΣSFR at kpc scales. Our results also suggest that Ph is the main parameter that modulates star formation at kpc scales, rather than individual components of the baryonic mass.

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

2016 ◽  
Vol 11 (S321) ◽  
pp. 99-101 ◽  
Author(s):  
Gerhard Hensler ◽  
Patrick Steyrleithner ◽  
Simone Recchi
Keyword(s):  
Star Formation ◽  
Massive Star ◽  
Dwarf Galaxies ◽  
Self Regulation ◽  
Mass Function ◽  
Initial Mass Function ◽  
Stellar Cluster ◽  
Stellar Feedback ◽  
Intermediate Mass Stars ◽  
The Impact

AbstractDue to their low masses dwarf galaxies experience low star-formation rates resulting in stellar cluster masses insufficient to fill the initial mass function (IMF) to the uppermost mass. Numerical simulations usually do not account for the completeness of the IMF, but treat a filed IMF by numbers, masses, and stellar feedback by fractions. To ensure that only entire stars are formed, we consider an IMF filled from the lower-mass regime and truncated where at least one entire massive star is formed.By 3D simulations we investigate the effects of two possible IMFs on the evolution of dwarf galaxies: filled vs. truncated IMF. For the truncated IMF the star-formation self-regulation is suppressed, while the energy release by typeII supernovae is larger, both compared to the filled IMF. Moreover, the abundance ratios of particular elements yielded from massive and intermediate-mass stars differ significantly between the two IMF distributions.

Self‐Regulation of Star Formation in Low‐Metallicity Clouds

2000 ◽  
Vol 537 (1) ◽  
pp. 50-54 ◽  
Author(s):  
Ryoichi Nishi ◽  
Motomichi Tashiro
Keyword(s):  
Star Formation ◽  
Self Regulation ◽  
Low Metallicity

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

2019 ◽  
Vol 491 (2) ◽  
pp. 1656-1672 ◽  
Author(s):  
Oscar Agertz ◽  
Andrew Pontzen ◽  
Justin I Read ◽  
Martin P Rey ◽  
Matthew Orkney ◽  
...  
Keyword(s):  
Star Formation ◽  
Galaxy Formation ◽  
Dwarf Galaxy ◽  
Self Regulation ◽  
Stellar Mass ◽  
Dark Matter Halo ◽  
V Band ◽  
The Galaxy ◽  
Unique Constraint ◽  
Low Mass

ABSTRACT 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 ($M_{\rm halo}=10^{9}{\, \rm M}_\odot$), simulated to redshift z = 0 at a mass and spatial resolution of $\sim 20{\, \rm M}_\odot$ 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 (∼104 K) even before cosmic reionization. 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.

scholarly journals The Iκεα model of feedback-regulated galaxy formation

2019 ◽  
Author(s):  
Mahavir Sharma ◽  
Tom Theuns
Keyword(s):  
Star Formation ◽  
Galaxy Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Self Regulation ◽  
Mass Function ◽  
Stellar Mass ◽  
Gas Content ◽  
Dark Matter Halo ◽  
Star Forming

Abstract We present the Iκεα model of galaxy formation, in which a galaxy’s star formation rate is set by the balance between energy injected by feedback from massive stars and energy lost by the deepening of the potential of its host dark matter halo due to cosmological accretion. Such a balance is secularly stable provided that the star formation rate increases with the pressure in the star forming gas. The Iκεα model has four parameters that together control the feedback from star formation and the cosmological accretion rate onto a halo. Iκεα reproduces accurately the star formation rate as a function of halo mass and redshift in the eagle hydrodynamical simulation, even when all four parameters are held constant. It predicts the emergence of a star forming main sequence along which the specific star formation rate depends weakly on stellar mass with an amplitude that increases rapidly with redshift. We briefly discuss the emerging mass-metallicity relation, the evolution of the galaxy stellar mass function, and an extension of the model that includes feedback from active galactic nuclei (AGN). These self-regulation results are independent of the star formation law and the galaxy’s gas content. Instead, star forming galaxies are shaped by the balance between stellar feedback and cosmological accretion, with accurately accounting for energy losses associated with feedback a crucial ingredient.

scholarly journals Detection of the self-regulation of star formation in galaxy discs

2019 ◽  
Vol 487 (1) ◽  
pp. L61-L66 ◽  
Author(s):  
Javier Zaragoza-Cardiel ◽  
Jacopo Fritz ◽  
Itziar Aretxaga ◽  
Divakara Mayya ◽  
Daniel Rosa-González ◽  
...  
Keyword(s):  
Star Formation ◽  
Self Regulation ◽  
The Self

scholarly journals Self-Regulated Star-Formation in Galaxies

1996 ◽  
Vol 171 ◽  
pp. 401-401
Author(s):  
J. Köppen ◽  
Ch. Theis ◽  
G. Hensler
Keyword(s):  
Star Formation ◽  
Time Scale ◽  
Star Formation Rate ◽  
Numerical Study ◽  
Ambient Medium ◽  
Formation Rate ◽  
Self Regulation ◽  
Physical Explanation ◽  
Star Formation In Galaxies ◽  
Gas Consumption

In the chemodynamical models of galaxies the energy input from massive stars into the ambient medium results in a self-regulation of the star formation rate (SFR). A thorough analytical and numerical study of this model shows that there is always a strong and negative feed-back, and the SFR becomes almost independent of the assumed stellar birth function (SBF). The time-scale to reach this equilibrium is much shorter than the gas consumption time-scale, hence the models evolve along this solution for most of the time. This mechanism provides a physical explanation for a quadratic dependence of the SFR on gas density. For more details cf. Köppen et al. (1995), A&A 296, 99 and in preparation.

Sign in / Sign up

Export Citation Format

Share Document