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- Title
Virial models and anisotropy of velocity dispersion in E-galaxies.
- Authors
Kondratyev, B. P.; Kireeva, E. N.
- Abstract
A tensor virial approach is used to construct detailed models of 22 flattened ellipticals. The models are combined with the new observational data: extended surface brightness distributions, the profiles of isophotes flattening and their twisting, the rotation curves and the velocity dispersion profiles. A key feature of these models is a rigorous consideration of the influence of the spatial shape of galaxies (oblate spheroid or triaxial ellipsoid) on the dynamics, as well as the structure of the internal density layers in these systems. For each galaxy the ratio of the rotational energy to the potential energy t = T rot | W | was found. Comparing this ratio with the observed v rot σ it is concluded that the majority of these systems cannot have isotropic velocity dispersion tensors. The anisotropy parameter β is limited to the interval 0.0 ≤ β ≤ 0.224 . An including of the gradient M / L profile decreases this parameter by 21 % for the M87 galaxy. A correlation was found between β and flattening of the outer regions for giant E-galaxies. Our results are compared with the results of other researchers. It was found that for small fast rotators our values β are in good agreement with those, obtained in the ATLAS 3 D project. However, for giant E-galaxies, our models provide better agreement with observations, than axisymmetric JAM models. In addition, our velocity dispersion anisotropy results are in satisfactory agreement with the results of high resolution cosmological simulations in the Illustris project.
- Subjects
ANISOTROPY; VELOCITY; DISPERSION (Chemistry); POTENTIAL energy; GALACTIC dynamics
- Publication
Astrophysics & Space Science, 2020, Vol 365, Issue 1, p1
- ISSN
0004-640X
- Publication type
Article
- DOI
10.1007/s10509-020-3728-4