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Session 62 - Elliptical Galaxies: Dynamics and the UV Upturn.
Oral session, Tuesday, January 14
The perturbative effects of myriads of stellar collisions on a self-graviting body can be investigated via the Impulse-Action method which extends the range of applicability of the Impulse Approximation. For an object of a given mass and internal structure, moving through a more extended stellar system of a specific distribution function, one can derive analytically or semi-analytically expressions for the object's deformation, its local rate of external two-body heating, the corresponding rate of mass loss and the trajectory of the evaporating object. The nature of the heating is different from the well known two-body relaxation and also different from tidal heating produced by the motion of an object through a surrounding gravitational field. The Impulse-Action method can be applied to several astrophysical problems such as, for example, the disruption of galactic clusters produced by encounters with giant molecular complexes and the evaporation of globular clusters due to scattering of massive black holes. One of the most interesting applications is the combination of dynamical friction and heating on orbits of infalling satellite galaxies inside the Milky Way's halo or of larger galaxies inside clusters.
Program listing for Tuesday