Séminaire / Seminar GReCO |
| « Separating expansion from collapse and generalizing TOV condition in spherically symmetric models with pressure, with ?-CDM examples » |
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M. Le Delliou |
| The Press-Schechter scheme for mass functions invokes Birkhoff''s theorem in the spherical collapse that yields non-linear collapse time. However, the theorem is only proven for asymptotic flatness (vacuum background). We investigate spherically symmetric solutions with pressure and discuss the existence of a dividing shell separating expanding and collapsing regions, for which we obtain gauge invariant conditions relating not only the intrinsic spatial curvature of the shells to the mass, but also a function of the pressure which we introduce and that generalises the Tolman-Oppenheimer-Volkov equilibrium condition. |
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Thursday 08 April 2010 - 11:00 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Pages web du séminaire / Seminar's webpage |