Séminaire/Seminar Galaxies |
| « Non-resonant relaxation of anisotropic globular clusters » |
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Kerwann Tep |
| Globular clusters are dense stellar systems whose core slowly contracts under the effect of self-gravity. The rate of this process was recently found to be directly linked to the initial amount of velocity anisotropy: tangentially anisotropic clusters contract faster than radially anisotropic ones. Furthermore, initially anisotropic clusters are found to generically tend towards more isotropic distributions during the onset of contraction. Chandrasekhar’s “non-resonant” theory of diffusion describes this relaxation as being driven by a sequence of local two-body deflections along each star’s orbit. When compared to N-body realisations of Plummer spheres with varying degrees of anisotropy, the NR theory is shown to recover remarkably well the detailed shape of the orbital diffusion and the associated initial isotropisation, up to a global multiplicative prefactor which increases with anisotropy. |
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jeudi 3 novembre 2022 - 11:30 Salle du Conseil Institut d'Astrophysique de Paris |
| Page web du séminaire / Seminar's webpage |