scholarly journals 6.2. Efficiency in nuclear fueling

1998 ◽  
Vol 184 ◽  
pp. 265-266
Author(s):  
M. Noguchi
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Numerical Simulations ◽  
Observational Data ◽  
Formation Process ◽  
Large Body ◽  
Merging Galaxies ◽  
Numerical Studies ◽  
Galactic Astronomy ◽  
Theoretical Side

Starburst phenomena in interacting and merging galaxies have been one of the most widely investigated subjects in today's galactic astronomy. On the theoretical side, a large body of numerical studies have been performed in order to interpret available observational data. Numerical simulations have been advanced to the point where they can include interstellar medium (ISM) and star formation process.

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 Tidal dwarf galaxies as laboratories of star formation and cosmology

2006 ◽  
Vol 2 (S237) ◽  
pp. 323-330 ◽  
Author(s):  
Pierre-Alain Duc ◽  
Frédéric Bournaud ◽  
Médéric Boquien
Keyword(s):  
Dark Matter ◽  
Star Formation ◽  
Numerical Simulations ◽  
Dwarf Galaxies ◽  
Star Clusters ◽  
Dense Core ◽  
Multi Wavelength ◽  
Interacting Systems ◽  
Super Star Clusters ◽  
Tidal Tails

AbstractStar formation may take place in a variety of locations in interacting systems: in the dense core of mergers, in the shock regions at the interface of the colliding galaxies and even within the tidal debris expelled into the intergalactic medium. Along tidal tails, objects may be formed with masses ranging from those of super-star clusters to dwarf galaxies: the so-called Tidal Dwarf Galaxies (TDGs). Based on a set of multi-wavelength observations and extensive numerical simulations, we show how TDGs may simultaneously be used as laboratories to study the process of star-formation (SFE, IMF) in a specific environment and as probes of various cosmological properties, such as the distribution of dark matter and satellites around galaxies.

scholarly journals Historical perspective on astrophysical MHD simulations

2010 ◽  
Vol 6 (S270) ◽  
pp. 7-17
Author(s):  
Michael L. Norman
Keyword(s):  
Star Formation ◽  
Magnetic Fields ◽  
Numerical Simulations ◽  
Historical Development ◽  
Adaptive Mesh Refinement ◽  
Historical Perspective ◽  
Adaptive Mesh ◽  
Personal Perspective ◽  
Mhd Simulations

AbstractThis contribution contains the introductory remarks that I presented at IAU Symposium 270 on “Computational Star Formation” held in Barcelona, Spain, May 31–June 4, 2010. I discuss the historical development of numerical MHD methods in astrophysics from a personal perspective. The recent advent of robust, higher-order accurate MHD algorithms and adaptive mesh refinement numerical simulations promises to greatly improve our understanding of the role of magnetic fields in star formation.

scholarly journals Secular evolution in galaxies

2006 ◽  
Vol 2 (S235) ◽  
pp. 19-23 ◽  
Author(s):  
F. Combes
Keyword(s):  
Star Formation ◽  
Numerical Simulations ◽  
Significant Role ◽  
High Frequency ◽  
Central Star ◽  
Barred Galaxies ◽  
Secular Evolution ◽  
Gas Accretion ◽  
Bar Formation

AbstractNew observations in favour of a significant role of secular evolution are reviewed: central star formation boosted in pseudo-bulge barred galaxies, relations between bulge and disk, evidence for rejuvenated bulges. Numerical simulations have shown that secular evolution can occur through a cycle of bar formation and destruction, in which the gas plays a major role. Since bars are weakened or destroyed in gaseous disks, the high frequency of bars observed today requires external cold gas accretion, to replenish the disk and allow a new bar formation. The rate of gas accretion from external filaments is compatible with what is observed in cosmological simulations.

scholarly journals Numerical Simulations of High‐Redshift Star Formation in Dwarf Galaxies

2003 ◽  
Vol 587 (1) ◽  
pp. 13-24 ◽  
Author(s):  
Konstantinos Tassis ◽  
Tom Abel ◽  
Greg L. Bryan ◽  
Michael L. Norman
Keyword(s):  
Star Formation ◽  
Numerical Simulations ◽  
Dwarf Galaxies ◽  
High Redshift

scholarly journals Efficiency of Stripping Mechanisms

2004 ◽  
Vol 217 ◽  
pp. 440-451 ◽  
Author(s):  
Françoise Combes
Keyword(s):  
Star Formation ◽  
Numerical Simulations ◽  
Cluster Formation ◽  
Observational Evidence ◽  
Physical Processes ◽  
Nuclear Activity ◽  
Tidal Interactions ◽  
Ram Pressure

There are several physical processes to remove gas from galaxies in clusters, with subsequent starvation and star formation quenching: tidal interactions between galaxies, or tidal stripping from the cluster potential itself, interactions with the hot intra-cluster medium (ICM) through ram pressure, turbulent or viscous stripping, or also outflows from star formation of nuclear activity, We review the observational evidence for all processes, and numerical simulations of galaxies in clusters which support the respective mechanisms. This allows to compare their relative efficiencies, all along cluster formation.

scholarly journals Star formation history and isophotal shapes of fossil central galaxies

2007 ◽  
Vol 3 (S245) ◽  
pp. 81-82
Author(s):  
Habib G. Khosroshahi ◽  
Louisa A. Nolan
Keyword(s):  
Star Formation ◽  
Numerical Simulations ◽  
Stellar Population ◽  
Stellar Populations ◽  
Elliptical Galaxies ◽  
Star Formation History ◽  
Spectral Fitting ◽  
Stellar Component ◽  
Formation History ◽  
Two Component

AbstractWe study the structure and stellar populations of the luminous elliptical galaxies dominating fossil groups and compare them with the brightest galaxies in ordinary groups. Despite being over-luminous, the fossil central galaxies do not show boxy stellar isophotes which are usually associated with luminous elliptical galaxies. Boxy isophotes, according to the numerical simulations, are produced in gas poor mergers. The isophotal shapes of the fossil central galaxies, therefore, suggest a gas rich merger for fossil central galaxies. Using a two-component spectral fitting, we show that the dominant stellar population of the fossil and non-fossil galaxies is old and the second population is either old or intermediate age. However, the second stellar component (recently-formed stars) in fossil central galaxies is significantly more metal poor than that in the brightest galaxies of non-fossil groups.

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