paper

Kinematics of globular cluster systems and the formation of early-type galaxies

arXiv:astro-ph/0509077 · doi:10.1111/j.1365-2966.2005.09517.x

Abstract

We numerically investigate the kinematic properties of globular cluster systems (GCSs) in E/S0 galaxies formed from dissipationless merging of spiral galaxies. The metal-poor globular clusters (MPCs) and metal-rich clusters (MRCs) in the merger progenitors are initially assumed to have spatial distributions consistent with the Milky Way GC system. Our principal results, which can be tested against observations, are as follows. Both MPCs and MRCs in elliptical galaxies formed from major mergers can exhibit significant rotation at large radii (20 kpc) due to the conversion of initial orbital angular momentum into intrinsic angular momentum of the remnant. MPCs show higher central velocity dispersions than MRCs for most major merger models. (where and , are the GCS maximum rotational velocity and central velocity dispersion of respectively) ranges from 0.2--1.0 and 0.1--0.9 for the MPCs and MRCs respectively, within for the remnant elliptical. For most merger remnant ellipticals, of GCSs within is greater than that of the field stars within . The radial profiles of rotational velocities and velocity dispersions of the GCSs depend upon the orbital configuration of the merger progenitors, their mass-ratios, and the viewing angle. For example, more flattened early-type galaxies, formed through mergers with small mass ratios ( 0.1), show little rotation in the outer MRCs. Two-dimensional (2D) velocity dispersion distributions of the GCSs of merger remnant ellipticals are generally flattened for both MPCs and MRCs, reflecting the fact that the GCSs have anisotropic velocity dispersions (abridged).

14 pages, 16 figures, accepted by MNRAS

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