相关论文: Global Collapses and Expansions in Star-Forming Cl…
A physical model and two-dimensional numerical method for computing the evolution and spectra of protostellar clouds are described. The physical model is based on a system of magneto-gasdynamical equations, including ohmic and ambipolar…
Recent models of molecular cloud formation and evolution suggest that such clouds are dynamic and generally exhibit gravitational collapse. We present a simple analytic model of global collapse onto a filament and compare this with our…
Observations that resolve nearby galaxies into individual regions across multiple phases of the gas-star formation-feedback ``matter cycle'' have provided a sharp new view of molecular clouds, star formation efficiencies, timescales for…
We investigate the formation and evolution of giant molecular clouds (GMCs) by the collision of convergent warm neutral medium (WNM) streams in the interstellar medium, in the presence of magnetic fields and ambipolar diffusion (AD),…
Super-sonic turbulence fragments molecular clouds (MC) into a very complex density field with density contrasts of several orders of magnitude. A fraction of the gas is locked into dense and gravitationally bound cores, which collapse as…
We present numerical investigations into the formation of massive stars from centrally condensed turbulent cores. The results of five hydrodynamical simulations are described, following the collapse of the core, fragmentation and the…
We present the results of a large suite of three-dimensional (3D) models of the collapse of magnetic molecular cloud cores using the adaptive mesh refinement (AMR) code Enzo2.2 in the ideal magnetohydrodynamics (MHD) approximation. The…
The processes regulating star formation in galaxies are thought to act across a hierarchy of spatial scales. To connect extragalactic star formation relations from global and kpc-scale measurements to recent cloud-scale resolution studies,…
Gravitational collapse is fundamental to star formation, yet direct kinematic evidence of infall at the core scale in high-mass star-forming regions remains poorly constrained. We present the first large-scale statistical study of infall…
Observed molecular clouds often appear to have very low star formation efficiencies and lifetimes an order of magnitude longer than their free-fall times. Their support is attributed to the random supersonic motions observed in them. We…
This paper gives a new way to diagnose the star-forming potential of a molecular cloud region from the probability density function of its column density (N-pdf). It gives expressions for the column density and mass profiles of a symmetric…
We present a model for the CO molecular line emission from high redshift Submillimeter Galaxies (SMGs). By combining hydrodynamic simulations of gas rich galaxy mergers with the polychromatic radiative transfer code, Sunrise, and the 3D…
Much of what we know about molecular clouds, and by extension star formation, comes from molecular line observations. Interpreting these correctly requires knowledge of the underlying molecular abundances. Simulations of molecular clouds…
Molecular clouds are active sites of star formation in galaxies, and their formation and evolution are largely affected by stellar feedback. This includes outflows and winds from newly formed stars, radiation from young clusters, and…
We apply an analytic theory for environmentally-dependent molecular cloud lifetimes to the Central Molecular Zone of the Milky Way. Within this theory, the cloud lifetime in the Galactic centre is obtained by combining the time-scales for…
Star formation is thought to be driven by two groups of mechanisms; spontaneous collapse and triggered collapse. Triggered star formation mechanisms further diverge into cloud-cloud collision (CCC), "collect and collapse" (C\&C) and shock…
(Abridged) Aims. We intend to derive statistical properties of stochastic gas motion inside the dense low mass star forming molecular cores traced by NH3(1,1) and (2,2) emission lines. Methods. We use the spatial two-point autocorrelation…
Models of self-gravitating gas in the early stages of pressure-free collapse are compared for initial states which are equilibrium layers, cylinders, and Bonnor-Ebert spheres. For each geometrical case the density profile has an inner…
We present the results of fully 3-D hydrodynamic simulations of the gravitational collapse of isolated, turbulent molecular cloud cores. Starting from initial states of hydrostatic equilibrium, we follow the collapse of both singular and…
Studies of the evolution of massive protostars and the evolution of their host molecular cloud cores are commonly treated as separate problems. However, interdependencies between the two can be significant. Here, we study the simultaneous…