Structural and dynamical modeling of WINGS clusters. II. The orbital
  anisotropies of elliptical, spiral and lenticular galaxies
  The Bayesian MAMPOSSt mass/orbit modeling algorithm is used to jointly fit
the distribution of elliptical, spiral (and irregular), and lenticular galaxies
in projected phase space, on 3 stacked clusters (with normalized positions and
velocities) of 54 regular clusters from the WINGS survey, with at least 30
member velocities. Our stacked clusters contain ~5000 galaxies with available
velocities and morphological types. 30 runs of MAMPOSSt with different priors
are presented. The highest MAMPOSSt likelihoods are obtained for generalized
NFW models with steeper inner slope, free-index Einasto models, and double NFW
models for the cluster and the brightest cluster galaxy. However, there is no
strong Bayesian evidence for a steeper profile than the NFW model. The mass
concentration matches the predictions from cosmological simulations.
Ellipticals usually trace best the mass distribution, while S0s are close.
Spiral galaxies show increasingly radial orbits at increasing radius, as do S0s
on two stacks, and ellipticals on one stack. The inner orbits of all three
types in the 3 stacks are consistent with isotropy. Spiral galaxies should
transform rapidly into early-types given their much larger extent in clusters.
Outer radial orbits are expected for the spirals, a consequence of their recent
radial infall into the cluster. The less radial orbits we find for early-types
could be related to the longer time spent by these galaxies in the cluster. We
demonstrate that two-body relaxation is too slow to explain the inner isotropy
of the early types, which suggests that inner isotropy is the consequence of
violent relaxation during major cluster mergers or dynamical friction and tidal
braking acting on subclusters. We propose that the inner isotropy of the
short-lived spirals is a selection effect of spirals passing only once through
pericenter before being transformed into early-type morphologies.
