相关论文: Control of star formation by supersonic turbulence
The question of what regulates star formation is a long standing issue. To investigate this issue, we run simulations of a kiloparsec cube section of a galaxy with three kinds of stellar feedback: the formation of HII regions, the explosion…
A general treatment of disk star formation is developed from a dissipative multi-phase model, with the dominant dissipation due to cloud collisions. The Schmidt-Kennicutt law emerges naturally for star-forming disks and starbursts. We…
Dense pockets of cold, molecular gas precede the formation of stars. During their infancy and later phases of evolution, stars inject considerable energy into the interstellar medium by driving shocks either due to ionising radiation or…
We derive and compare six theoretical models for the star formation rate (SFR) - the Krumholz & McKee (KM), Padoan & Nordlund (PN), and Hennebelle & Chabrier (HC) models, and three multi-freefall versions of these, suggested by HC - all…
Context. Stellar feedback regulates star formation and shapes the interstellar medium, yet its role during the collapse of molecular clouds remains uncertain over a wide range of initial conditions. Aims. We explore how stellar winds and…
Star formation in our Galaxy occurs in molecular clouds that are self-gravitating, highly turbulent, and magnetized. We study the conditions under which cloud cores inherit large-scale magnetic field morphologies and how the field is…
We present two dimensional hydrodynamic calculations of free expanding supergalactic winds, taking into consideration strong radiative cooling. Our main premise is that supergalactic winds are powered by collections of superstar clusters.…
We review theoretical models of the early stages of star formation, in which gravitational collapse is strongly regulated by magnetic fields and the associated process of ambipolar diffusion. We discuss results of numerical simulations and…
Recent observations have revealed massive galactic molecular outflows that may have physical conditions (high gas densities) required to form stars. Indeed, several recent models predict that such massive galactic outflows may ignite star…
The star formation rate (SFR), the number of stars formed per unit of time, is a fundamental quantity in the evolution of the Universe. While turbulence is believed to play a crucial role in setting the SFR, the exact mechanism remains…
"The purpose of numerical models is not numbers but insight." (Hamming) In the spirit of this adage, and of Don Cox's approach to scientific speaking, we discuss the questions that the latest generation of numerical models of the…
Turbulence is ubiquitous in the insterstellar medium and plays a major role in several processes such as the formation of dense structures and stars, the stability of molecular clouds, the amplification of magnetic fields, and the…
The pressure exerted by massive stars' radiation fields is an important mechanism regulating their formation. Detailed simulation of massive star formation therefore requires an accurate treatment of radiation. However, all published…
We suggest that molecular cloud (MC) turbulence is a consequence of the very process of MC formation by collisions of larger-scale flows in the diffuse atomic gas, which generate turbulence in the accumulated gas through bending- mode…
We investigate the formation and early evolution of star clusters assuming that they form from a turbulent starless clump of given mass bounded inside a parent self-gravitating molecular cloud characterized by a particular mass surface…
The interstellar medium (ISM) provides a unique laboratory for highly supersonic, driven hydrodynamics turbulence. We present a theory of such turbulence, confirm it by numerical simulations, and use the results to explain observational…
The major questions relevant to star and planet formation are: What controls the rate, efficiency, spatial clustering, multiplicity, and initial mass function of star formation, now and in the past? What are the major feedback mechanisms…
Feedback from protostellar outflows can influence the nature of turbulence in star forming regions even if they are not the primary source of velocity dispersion for all scales of molecular clouds. For the rate and power expected in star…
A simple model of gas accretion in young galaxy disks suggests that fast turbulent motions can be driven by accretion energy for a time t_acc~2(epsilon^{0.5} GM^2/xi V^3)^{0.5} where epsilon is the fraction of the accretion energy going…
Gravity drives the collapse of molecular clouds through which stars form, yet the exact role of gravity in cloud collapse remains a complex issue. Studies point to a picture where star formation occurs in clusters. In a typical, pc-sized…