The origin of globular cluster systems from cosmological simulations - AstrophysicsReport as inadecuate

The origin of globular cluster systems from cosmological simulations - Astrophysics - Download this document for free, or read online. Document in PDF available to download.

Abstract: We investigate the structural, kinematical, and chemical properties ofglobular cluster systems GCSs in galaxies of different Hubble types in aself-consistent manner based on high-resolution cosmological N-body simulationscombined with semi-analytic models of galaxy and globular cluster GCformation. We focus on correlations between the physical properties of GCSs andthose of their host galaxies for about 10^5 simulated galaxies located at thecentres of dark matter halos i.e. we do not consider satellite galaxies insub-halos. Our principal results, which can be tested against observations,are as follows. The majority about 90% of GCs currently in halos are formedin low-mass galaxies at redshifts greater than 3 with mean formation redshiftsof z = 5.7 12.7 Gyrs ago and 4.3 12.3 Gyrs ago for metal-poor GCs MPC andmetal-rich GCs MRCs, respectively. About 52 % of galaxies with GCs show clearbimodality in their metallicity distribution functions, though less luminousgalaxies with M B fainter than -17 are much less likely to show bimodalityowing to little or no MRCs. The number fraction of MRCs does not depend onHubble type but is generally smaller for less luminous galaxies. The specificfrequencies S N of GCSs are typically higher in ellipticals S N ~ 4.0than in spirals S N ~ 1.8, and higher again S N ~ 5.0 for galaxies locatedat the centers of clusters of galaxies. The total number of GCs per unit halomass does not depend strongly on M B or Hubble type of the host galaxy. Themean metallicities of MPCs and MRCs depend on M B such that they are higher inmore luminous galaxies, though the dependence is significantly weakerfor MPCs.

Author: K. Bekki, H. Yahagi, M. Nagashima, D. A. Forbes


Related documents