SCYON Abstract

Received on February 20 2007

The present day mass function in the central region of the Arches cluster

Authors	Simon Portegies Zwart, Evghenii Gaburov, Hui-Chen Chen, and M. Atakan Gurkan
Affiliation	University of Amsterdam
Submitted to	Monthly Notices of the Royal Astronomical Society
Contact	spz@science.uva.nl
URL	http://staff.science.uva.nl/~spz/
Links

Abstract

We study the evolution of the mass function in young and dense star clusters by means of direct N-body simulations. Our main aim is to explain the recent observations of the relatively flat mass function observed near the centre of the Arches star cluster. In this region, the power law index of the mass function for stars more massive than about 5-6 M(sun), is larger than the Salpeter value by about unity; whereas further out, and for the lower mass stars, the mass function resembles the Salpeter distribution. We show that the peculiarities in the Arches mass function can be explained satisfactorily without primordial mass segregation. We draw two conclusions from our simulations: 1) The Arches initial mass function is consistent with a Salpeter slope down to ~ 1 M(sun), 2) The cluster is about half way towards core collapse. The cores of other star clusters with characteristics similar to those of the Arches are expected to show similar flattening in the mass functions for the high mass (≈> 5 M(sun)) stars.