Bibcode
Bekki, K.; Beasley, Michael A.; Brodie, Jean P.; Forbes, Duncan A.
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 363, Issue 4, pp. 1211-1222.
Advertised on:
11
2005
Citations
48
Refereed citations
42
Description
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 GCS. 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.
Vm/σ0 (where Vm and
σ0 are the GCS maximum rotational velocity and central
velocity dispersion, respectively) ranges from 0.2 to 1.0 and from 0.1
to 0.9 for the MPCs and MRCs, respectively, within 6Re for
the remnant elliptical. For most merger remnant ellipticals,
Vm/σ0 of GCSs within 6Re is
greater than that of the field stars within 2Re. 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. The 2D
distributions of the line-of-sight velocity of the GCSs in some remnant
ellipticals show minor-axis rotation, particularly for MRCs. The
kinematic properties of MPCs in merger remnant ellipticals strongly
resemble those of the surrounding dark matter. This implies that the
kinematics of MPCs in such galaxies can be used to probe the kinematic
properties of their dark matter haloes. We discuss these results in the
context of GC and galaxy formation. We note a possible difference in the
GC kinematics between field and cluster Es and explain how GC kinematics
may help us understand the origin of S0 galaxies.