$\Lambda$ effect in the cosmological expansion of voids
Résumé
The dynamical effect of the cosmological constant $\Lambda$ on a single spherical void evolving in a Friedmann-Lemaître universe is investigated within a non linear perturbation of Newton-Friedmann models. The void expansion shows a huge initial burst, which freezes asymptotically up to match Hubble expansion. $\Lambda$-effect on the kinematics intervenes significantly by amplifying the expansion rate at redshift $z\sim 1.7$, what corresponds to the loitering period. As a result, the size increases with $\Lambda$ (what can be interpreted by the "repulsion gravitational of vacuum"). A stability criterion is ensured for spatially closed Friedmann models, since the empty regions are swept out.