We have compared the halo kinematics traced by globular clusters (GCs) and
planetary nebulae (PNe) for two elliptical galaxies in the Fornax and Virgo
clusters NGC 1399 and NGC 4649, and for the merger remnant NGC 5128 (Centaurus
A). We find differences in the rotational properties of the PN, red GC, and
blue GC systems in all these three galaxies. NGC 1399 PNe and GCs show line of
sight velocity distributions in specific regions that are significantly
different, based on Kolmogorov-Smirnov tests. The PN system shows multi-spin
components, with nearly opposite direction of rotation in the inner and the
outer parts. The GCs velocity field is not point-symmetric in the outer regions
of the galaxy, indicating that the system has not reached dynamical equilibrium
yet. In NGC 4649 PNe, red and blue GCs have different rotation axes and
rotational velocities. Finally, in NGC 5128 both PNe and GCs deviate from
equilibrium in the outer regions of the galaxy, and in the inner regions the PN
system is rotationally supported, whereas the GC system is dominated by
velocity dispersion. The observed different kinematic properties, including
deviations from point-symmetry, between PNe and GCs suggest that these systems
are accreted at different times by the host galaxy, and the most recent
accretion took place only few Gyr ago.We discuss two scenarios which may
explain some of these differences: i) tidal stripping of loosely-bound GCs, and
ii) multiple accretion of low luminosity and dwarf galaxies. Because these two
mechanisms affect mostly the GC system, differences with the PNe kinematics can
be expected.Comment: 14 pages, 13 figures, Accepted for publication in MNRAS. This new
version contains an improved analysis, which includes the study of
point-symmetry in the velocity fields and its implications for dynamical
equilibriu
