相关论文: Competitive Accretion and the IMF
Competitive accretion, a process to explain the origin of the IMF, occurs when stars in a common gravitational potential accrete from a distributed gaseous component. We show that concerns recently raised on the efficiency of competitive…
We present a simple physical mechanism that can account for the observed stellar mass spectrum for masses $\ms \simgreat 0.5 \solm$. The model depends solely on the competitive accretion that occurs in stellar clusters where each star's…
Observations have revealed that most stars are born in clusters. As these clusters typically contain more mass in gas than in stars, accretion can play an important role in determining the final stellar masses. Numerical simulations of gas…
We investigate the physics of gas accretion in young stellar clusters. Accretion in clusters is a dynamic phenomenon as both the stars and the gas respond to the same gravitational potential. Accretion rates are highly non-uniform with…
The observed slope at the high-mass end of the initial mass function (IMF) displays a remarkable universality in a wide variety of physical environments. We predict that competitive accretion, the ongoing accretion of gas from a common…
There are now two dominant models of how stars form: gravitational collapse theory holds that star-forming molecular clumps, typically hundreds to thousands of solar masses in mass, fragment into gaseous cores that subsequently collapse to…
The baryonic fraction of galaxies is observed to vary with the mass of its dark matter (DM) halo. Low-mass galaxies have low baryonic fractions which increase to a maximum for masses near $10^{12}\ M_{\odot}$, and decreases thereafter with…
We report a set of numerical experiments aimed at addressing the applicability of competitive accretion to explain the high-mass end of the stellar initial mass function in a sheet geometry with shallow gravitational potential, in contrast…
Numerical simulations have shown the occurence of a scenario termed ''super-competitive accretion'', a term that describes a situation where only the central few objects grow supermassive while a larger number of stars compete for the…
A model of core-clump accretion with equally likely stopping describes star formation in the dense parts of clusters, where models of isolated collapsing cores may not apply. Each core accretes at a constant rate onto its protostar, while…
An isolated star moving supersonically through a uniform gas accretes material from its gravitationally-induced wake. The rate of accretion is set by the accretion radius of the star and is well-described by classical Bondi-Hoyle-Lyttleton…
The two main competing theories proposed to explain the formation of massive ($>10$M$_\odot$) stars -- competitive accretion and monolithic core collapse -- make different observable predictions for the environment of the massive stars…
We consider here the collective accretion of gas by globular clusters and dwarf galaxies moving through the interstellar medium. In the limit of high velocity and/or sound speed of the ISM, the collective potential of the cluster is…
We consider the conditions required for a cluster core to shrink, by adiabatic accretion of gas from the surrounding cluster, to densities such that stellar collisions are a likely outcome. We show that the maximum densities attained, and…
(abridged) We develop a model which describes the coevolution of the mass function of dense cores and of the IMF in a protocluster clump. In the model, cores injected in the clump evolve under the effect of gas accretion. Accretion onto the…
We investigate how the dynamical state of a turbulently supported, 1000 solar mass, molecular cloud affects the properties of the cluster it forms, focusing our discussion on the star formation efficiency (SFE) and the initial mass function…
The formation of star clusters involves the growth of smaller, gas-rich subclusters through accretion of gas from the giant molecular cloud within which the subclusters are embedded. The two main accretion mechanisms responsible for this…
The enormous radiative and mechanical luminosities of massive stars impact a vast range of scales and processes, from the reionization of the universe, to the evolution of galaxies, to the regulation of the interstellar medium, to the…
Young stars orbiting in the gravitational potential well of forming star clusters pass through the cluster's dense molecular gas and can experience Bondi-Hoyle accretion from reservoirs outside their individual protostellar cloud cores.…
The formation of massive stars is currently an unsolved problems in astrophysics. Understanding the formation of massive stars is essential because they dominate the luminous, kinematic, and chemical output of stars. Furthermore, their…