Gravitational Focusing and the Star Cluster Initial Mass Function

Abstract

We discuss the possibility that gravitational focusing, is responsible for the power-law mass function of star clusters $N(\log M)\propto M^{-1}$. This power law can be produced asymptotically when the mass accretion rate of an object depends upon the mass of the accreting body as $\dot{M}\propto M^2$. While Bondi-Hoyle-Littleton accretion formally produces this dependence on mass in a uniform medium, realistic environments are much more complicated. However, numerical simulations in SPH allowing for sink formation yield such an asymptotic power-law mass function. We perform pure N-body simulations to isolate the effects of gravity from those of gas physics and to show that clusters naturally result with the power-law mass distribution. We also consider the physical conditions necessary to produce clusters on appropriate timescales. Our results help support the idea that gravitationally-dominated accretion is the most likely mechanism for producing the cluster mass function.

6 pages; accepted by ApJ

References in corpus (5)

• On the Star Formation Rate - Brightest Cluster Relation: Estimating the peak SFR in post-merger galaxies
• On the Structure of the Orion A Cloud and the Formation of the Orion Nebula Cluster
• Super Star Cluster Velocity Dispersions and Virial Masses in the M82 Nuclear Starburst
• Bondi-Hoyle-Littleton accretion and the upper mass stellar IMF
• The JCMT Gould Belt Survey: A First Look at Southern Orion A with SCUBA-2

Cited by in corpus (2)

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