Structural and dynamical modeling of WINGS clusters. II. The orbital anisotropies of elliptical, spiral and lenticular galaxies. (arXiv:1901.06393v1 [astro-ph.GA])

Structural and dynamical modeling of WINGS clusters. II. The orbital anisotropies of elliptical, spiral and lenticular galaxies. (arXiv:1901.06393v1 [astro-ph.GA])
<a href="http://arxiv.org/find/astro-ph/1/au:+Mamon_G/0/1/0/all/0/1">G. A. Mamon</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Cava_A/0/1/0/all/0/1">A. Cava</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Biviano_A/0/1/0/all/0/1">A. Biviano</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Moretti_A/0/1/0/all/0/1">A. Moretti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Poggianti_B/0/1/0/all/0/1">B. Poggianti</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Bettoni_D/0/1/0/all/0/1">D. Bettoni</a>

The orbital shapes of galaxies is a probe of their formation and evolution.
The Bayesian MAMPOSSt mass/orbit modeling algorithm is used to jointly fit the
distribution of elliptical (E), spiral/Irr (S), and S0 galaxies in projected
phase space, on 3 pseudo-clusters (built by stacking the clusters after
renormalizing their positions and velocities) of 54 regular clusters from the
WINGS Survey, with at least 30 member velocities. Our pseudo-clusters (stacks)
contain nearly 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 or
a double NFW cluster+BCG model. 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. Spirals show increasingly radial orbits
at increasing radius, as do S0s on two stacks, and Es on one stack. The inner
orbits of all 3 types in the 3 stacks are consistent with isotropy. Spirals
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
Ellipticals & S0s could be related to the longer time they spend in the
cluster. We show that 2-body relaxation is too slow to explain the inner
isotropy of the E/S0s, 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 E/S0 morphologies.

The orbital shapes of galaxies is a probe of their formation and evolution.
The Bayesian MAMPOSSt mass/orbit modeling algorithm is used to jointly fit the
distribution of elliptical (E), spiral/Irr (S), and S0 galaxies in projected
phase space, on 3 pseudo-clusters (built by stacking the clusters after
renormalizing their positions and velocities) of 54 regular clusters from the
WINGS Survey, with at least 30 member velocities. Our pseudo-clusters (stacks)
contain nearly 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 or
a double NFW cluster+BCG model. 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. Spirals show increasingly radial orbits
at increasing radius, as do S0s on two stacks, and Es on one stack. The inner
orbits of all 3 types in the 3 stacks are consistent with isotropy. Spirals
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
Ellipticals & S0s could be related to the longer time they spend in the
cluster. We show that 2-body relaxation is too slow to explain the inner
isotropy of the E/S0s, 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 E/S0 morphologies.

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