scholarly journals The Supernova – ISM/Star-formation interplay

2013 ◽  
Vol 9 (S296) ◽  
pp. 265-272
Author(s):  
Gerhard Hensler
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Molecular Clouds ◽  
Numerical Models ◽  
Evolutionary Models ◽  
Star Forming ◽  
Supernova Explosions ◽  
Representative Selection ◽  
Supernova Feedback ◽  
Selection Of

AbstractSupernovae are the most energetic stellar events and influence the interstellar medium by their gasdynamics and energetics. By this, both also affect the star formation positively and negatively. In this paper, we review the complexity of investigations aiming at understanding the interchange between supernova explosions with the star-forming molecular clouds. Commencing from analytical studies the paper advances to numerical models of supernova feedback from superbubble scales to galaxy structure. We also discuss parametrizations of star-formation and supernova-energy transfer efficiencies. Since evolutionary models from the interstellar medium to galaxies are numerous and are applying multiple recipes of these parameters, only a representative selection of studies can be discussed here.

scholarly journals Supernova Feedback on the Interstellar Medium and Star Formation

2010 ◽  
Vol 6 (S270) ◽  
pp. 309-317
Author(s):  
Gerhard Hensler
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Molecular Clouds ◽  
Numerical Models ◽  
Evolutionary Models ◽  
Star Forming ◽  
Hot Gas ◽  
Representative Selection ◽  
Supernova Feedback ◽  
Selection Of

AbstractSupernovae are the most energetic stellar events and influence the interstellar medium by their gasdynamics and energetics. By this, both also affect the star formation positively and negatively. In this paper, we review the development of the complexity of investigations aiming at understanding the interchange between supernovae and their released hot gas with the star-forming molecular clouds. Commencing from analytical studies the paper advances to numerical models of supernova feedback from superbubble scales to galaxy structure. We also discuss parametrizations of star-formation and supernova-energy transfer efficiencies. Since evolutionary models from the interstellar medium to galaxies are numerous and apply multiple recipes of these parameters, only a representative selection of studies can be discussed here.

Formation of structure in star-forming clouds

1990 ◽  
Vol 68 (9) ◽  
pp. 808-823
Author(s):  
Ralph E. Pudritz
Keyword(s):  
Star Formation ◽  
Magnetic Fields ◽  
Interstellar Medium ◽  
Physical Properties ◽  
Molecular Clouds ◽  
Fundamental Theory ◽  
Wave Pressure ◽  
Star Forming ◽  
Effective Wave ◽  
Hydromagnetic Waves

Star formation occurs in massive, dense, molecular clouds in the interstellar medium. These clouds have a rich substructure consisting of dense clumps and extended filaments. Since stars only form within these dense clumps, any fundamental theory of star formation must predict their physical properties. This review focusses on the physics of molecular clouds and discusses in this context a particular mechanism for the formation of structure that is well supported by the observations. Strong hydromagnetic waves are likely to be excited in molecular clouds since it is observed that cloud magnetic fields have energy densities close to gravity. These waves support the cloud against global gravitational collapse by providing an effective wave "pressure". This review also shows that waves may control the formation of structure in molecular clouds.

scholarly journals Stochastic Star Formation and Magnetic Fields

1990 ◽  
Vol 140 ◽  
pp. 257-258
Author(s):  
J. V. Feitzinger ◽  
E. Harfst ◽  
J. Spicker
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Molecular Clouds ◽  
Large Scale ◽  
Spiral Structure ◽  
Galactic Plane ◽  
Molecular Gas ◽  
Cell Content ◽  
Star Forming ◽  
Flat Rotation Curves

The model of selfpropagating star formation uses local processes (200 pc cell size) in the interstellar medium to simulate the large scale cooperative behaviour of spiral structure in galaxies. The dynamic of the model galaxies is taken into account via the mass distribution and the resulting rotation curve; flat rotation curves are used. The interstellar medium is treated as a multiphase medium with appropriate cooling times and density history. The phases are: molecular gas, cool HI gas, warm intercloud and HII gas and hot coronal fountain gas. A detailed gas reshuffeling between the star forming cells in the plane and outside the galactic plane controls the cell content. Two processes working stochastically are incooperated: the building and the decay of molecular clouds and the star forming events in the molecular clouds.

scholarly journals The Cloud Factory I: Generating resolved filamentary molecular clouds from galactic-scale forces

2019 ◽  
Vol 492 (2) ◽  
pp. 1594-1613 ◽  
Author(s):  
Rowan J Smith ◽  
Robin G Treß ◽  
Mattia C Sormani ◽  
Simon C O Glover ◽  
Ralf S Klessen ◽  
...  
Keyword(s):  
Star Formation ◽  
Differential Rotation ◽  
Molecular Clouds ◽  
Star Clusters ◽  
Star Forming ◽  
Velocity Gradients ◽  
Tracer Particles ◽  
Galactic Potential ◽  
Internal Velocity ◽  
Supernova Feedback

ABSTRACT We introduce a new suite of simulations, ‘The Cloud Factory’, which self-consistently forms molecular cloud complexes at high enough resolution to resolve internal substructure (up to 0.25 M⊙ in mass) all while including galactic-scale forces. We use a version of the arepo code modified to include a detailed treatment of the physics of the cold molecular ISM, and an analytical galactic gravitational potential for computational efficiency. The simulations have nested levels of resolution, with the lowest layer tied to tracer particles injected into individual cloud complexes. These tracer refinement regions are embedded in the larger simulation so continue to experience forces from outside the cloud. This allows the simulations to act as a laboratory for testing the effect of galactic environment on star formation. Here we introduce our method and investigate the effect of galactic environment on filamentary clouds. We find that cloud complexes formed after a clustered burst of feedback have shorter lengths and are less likely to fragment compared to quiescent clouds (e.g. the Musca filament) or those dominated by the galactic potential (e.g. Nessie). Spiral arms and differential rotation preferentially align filaments, but strong feedback randomizes them. Long filaments formed within the cloud complexes are necessarily coherent with low internal velocity gradients, which has implications for the formation of filamentary star-clusters. Cloud complexes formed in regions dominated by supernova feedback have fewer star-forming cores, and these are more widely distributed. These differences show galactic-scale forces can have a significant impact on star formation within molecular clouds.

Discussion session on star formation, molecular clouds and the interstellar medium

1994 ◽  
Vol 217 (1-2) ◽  
pp. 227-230
Author(s):  
Karen M. Strom ◽  
Lennart Nordh ◽  
Eli Dwek
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Molecular Clouds ◽  
Discussion Session

scholarly journals The Violent Interstellar Medium of Nearby Dwarf Galaxies

1999 ◽  
Vol 16 (1) ◽  
pp. 106-112 ◽  
Author(s):  
Fabian Walter
Keyword(s):  
Interstellar Medium ◽  
Gamma Ray ◽  
Dwarf Galaxies ◽  
Young Star ◽  
Stellar Winds ◽  
Star Forming ◽  
Star Forming Regions ◽  
Supernova Explosions ◽  
High Velocity Clouds ◽  
Ob Associations

AbstractHigh resolution HI observations of nearby dwarf galaxies (most of which are situated in the M81 group at a distance of about 3·2 Mpc) reveal that their neutral interstellar medium (ISM) is dominated by hole-like features most of which are expanding. A comparison of the physical properties of these holes with the ones found in more massive spiral galaxies (such as M31 and M33) shows that they tend to reach much larger sizes in dwarf galaxies. This can be understood in terms of the galaxy's gravitational potential. The origin of these features is still a matter of debate. In general, young star forming regions (OB-associations) are held responsible for their formation. This picture, however, is not without its critics and other mechanisms such as the infall of high velocity clouds, turbulent motions or even gamma ray bursters have been recently proposed. Here I will present one example of a supergiant shell in IC 2574 which corroborates the picture that OB associations are indeed creating these structures. This particular supergiant shell is currently the most promising case to study the effects of the combined effects of stellar winds and supernova explosions which shape the neutral interstellar medium of (dwarf) galaxies.

scholarly journals Symposium Summary: Fragmentation and Star Formation in Molecular Clouds

1991 ◽  
Vol 147 ◽  
pp. 379-386
Author(s):  
A. E. Glassgold
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Molecular Clouds ◽  
Substantial Progress ◽  
Made In ◽  
Easy Solution

This Symposium on fragmentation and star formation has dealt with the heart of the study of molecular clouds, which is how they form stars. This problem is one of the most profound and challenging problems in all of astrophysics. The complexity of the interstellar medium adds to its difficulty and we cannot expect a quick and easy solution. Nonetheless, the reports presented at this Symposium indicate that substantial progress is being made in this field.

scholarly journals Relations Between Star Formation and the Interstellar Medium

1998 ◽  
Vol 179 ◽  
pp. 165-171 ◽  
Author(s):  
Y. Fukui ◽  
Y. Yonekura
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Formation Process ◽  
Molecular Clouds ◽  
Future Prospects

We review observational results concerning star formation and dense molecular clouds, the interstellar medium most relevant to star-formation process, as well as future prospects.

Molecular Clouds

1977 ◽  
Vol 75 ◽  
pp. 37-54 ◽  
Author(s):  
P. Thaddeus
Keyword(s):  
Star Formation ◽  
Interstellar Medium ◽  
Molecular Clouds ◽  
Physical State ◽  
Molecular Gas ◽  
Spectroscopic Techniques ◽  
Low Density ◽  
Recombination Line ◽  
Interstellar Gas ◽  
Impossible Task

To attempt to understand star formation without knowing the physical state of the dense interstellar molecular gas from which stars are made is an almost impossible task. Star formation has developed late as a branch of astrophysics largely for lack of observational data, and in particular, has lagged badly behind the study of the atomic and ionized components of the interstellar gas because spectroscopic techniques which work well at low density have an unfortunate tendency to fail when the density is high. Optical spectroscopy, which has been applied to the interstellar medium for over 70 years, has made little progress in regions of high density because of obscuration, and the same is true a fortiori of spacecraft spectroscopy in the UV; radio 21-cm and recombination line observations, although unhampered by obscuration, are unsatisfactory because the dense condensations are almost entirely molecular in composition.

scholarly journals A Guide to Comparisons of Star Formation Simulations with Observations

2010 ◽  
Vol 6 (S270) ◽  
pp. 511-519 ◽  
Author(s):  
Alyssa A. Goodman
Keyword(s):  
Star Formation ◽  
Spectral Line ◽  
Molecular Clouds ◽  
Direct Relationship ◽  
Statistical Tests ◽  
Random Processes ◽  
Mass Function ◽  
Star Forming ◽  
Star Forming Regions ◽  
Taste Testing

AbstractWe review an approach to observation-theory comparisons we call “Taste-Testing.” In this approach, synthetic observations are made of numerical simulations, and then both real and synthetic observations are “tasted” (compared) using a variety of statistical tests. We first lay out arguments for bringing theory to observational space rather than observations to theory space. Next, we explain that generating synthetic observations is only a step along the way to the quantitative, statistical, taste tests that offer the most insight. We offer a set of examples focused on polarimetry, scattering and emission by dust, and spectral-line mapping in star-forming regions. We conclude with a discussion of the connection between statistical tests used to date and the physics we seek to understand. In particular, we suggest that the “lognormal” nature of molecular clouds can be created by the interaction of many random processes, as can the lognormal nature of the IMF, so that the fact that both the “Clump Mass Function” (CMF) and IMF appear lognormal does not necessarily imply a direct relationship between them.

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