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DYNAMICAL EVOLUTION OF THE M87 GLOBULAR CLUSTER SYSTEM

  • Kim, Sung-Soo (Department of Astronomy & Space Science, Kyung Hee University) ;
  • Shin, Ji-Hye (Department of Astronomy & Space Science, Kyung Hee University) ;
  • Jin, Ho (School of Space Research, Kyung Hee University)
  • Received : 2010.04.20
  • Accepted : 2010.06.12
  • Published : 2010.08.31

Abstract

We study the dynamical evolution of the M87 globular cluster (GC) system using the most advanced and realistic Fokker-Planck (FP) model.By comparing our FP models with both mass function (MF) and radial distribution (RD) of the observed GC system, we find the best-fit initial (at M87's age of 2-3 Gyr) MF and RD for three GC groups: all GCs, blue GCs, and red GCs. We estimate the initial total mass in GCs to be $1.8^{+0.3}_{-0.2}{\times}10^{10}M_{\bigodot}$, which is about 100 times larger than that of the Milky Way GC system. We also find that the fraction of the total mass currently in GCs is 34\%. When blue and red GCs are fitted separately, blue GCs initially have a larger total mass and a shallower radial distribution than red GCs. If one assumes that most of the significant major merger events of M87 have ended by the age of 2-3 Gyr, our finding that blue (metal-poor) GCs initially had a shallower radial distribution supports the major merger scenario for the origin of metallicity bimodality.

Keywords

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