相关论文: Gravity, Turbulence, and Star Formation
Observational advances over the last decade reveal that star formation is associated with the simultaneous presence of gravitationally collapsing gas, bipolar outflow, and an accretion disk. Two theoretical views of star formation suppose…
Massive galaxy clusters are filled with a hot, turbulent and magnetized intra-cluster medium. Still forming under the action of gravitational instability, they grow in mass by accretion of supersonic flows. These flows partially dissipate…
The Schmidt-Kennicutt relation links the surface densities of gas to the star formation rate in galaxies. The physical origin of this relation, and in particular its break, i.e. the transition between an inefficient regime at low gas…
Molecular clouds are prime locations to study the process of star formation. These clouds contain filamentary structures and cores, which are crucial sites for the formation of young stars. The star-formation process has been investigated…
Molecular clouds (MCs) are highly structured and ``turbulent''. Colliding gas streams of atomic hydrogen have been suggested as a possible source of MCs, imprinting the filamentary structure as a consequence of dynamical and thermal…
The interaction of magnetic turbulence and relativistic particles is a important process for understanding particles propagation and acceleration in many astrophysical environments. Large-scale turbulence can be generated in the…
Direct evidence for in situ particle acceleration mechanisms in the inter-galactic-medium (IGM) is provided by the diffuse Mpc--scale synchrotron emissions observed from galaxy clusters. It has been proposed that MHD turbulence, generated…
In this course we review the theory of incompressible homogeneous turbulence at an elementary level, and discuss the similarities and differences expected in the compressible case, relevant to the interstellar medium and molecular clouds.…
(Abridged) The building blocks of galaxies are star clusters. These form with low-star formation efficiencies and, consequently, loose a large part of their stars that expand outwards once the residual gas is expelled by the action of the…
Frequent supernova explosions in compact starburst regions are a main shaper of these regions' interstellar media (ISM). In most starbursts, the supernova remnants blast open a hot phase that fills the regions and launches a superwind.…
Most, perhaps all, stars go through a phase of vigorous outflow during formation. We examine, through 3D MHD simulation, the effects of protostellar outflows on cluster formation. We find that the initial turbulence in the cluster-forming…
We present first results concerning the metallicities and stellar populations of galaxies formed in a cosmologically motivated simulation. The calculations include dark matter, gas dynamics, radiation processes, star formation, supernovae…
The interstellar medium of galaxies is composed of multiple phases, including molecular, atomic, and ionized gas, as well as dust. Stars are formed within this medium from cold molecular gas clouds, which collapse due to their gravitational…
We revisit an alternate explanation for the turbulent nature of molecular clouds - namely, that velocity dispersions matching classical predictions of driven turbulence can be generated by the passage of clumpy material through a shock.…
During the last two decades, the focus of star formation research has shifted from understanding the collapse of a single dense core into a star to studying the formation hundreds to thousands of stars in molecular clouds. In this chapter,…
We investigate collisions between giant molecular clouds (GMCs) as potential generators of their internal turbulence. Using magnetohydrodynamic (MHD) simulations of self-gravitating, magnetized, turbulent, GMCs, we compare kinematic and…
Observations show that galaxies and their interstellar media are pervaded by strong magnetic fields with energies in the diffuse component being at least comparable to the thermal and even as large or larger than the turbulent energy. Such…
Stars form within molecular clouds but our understanding of this fundamental process remains hampered by the complexity of the physics that drives their evolution. We review our observational and theoretical knowledge of molecular clouds…
In recent works, we proposed a hypothesis, according to which turbulence in gases is created by the mean field effect of an intermolecular potential. We discovered that, in a numerically simulated inertial flow, turbulent solutions indeed…
Large-scale star formation in disk galaxies is hypothesized to be driven by global gravitational instability. The observed gas surface density is commonly used to compute the strength of gravitational instability, but according to this…