Spherical collapse model with shear and angular momentum in dark energy
  cosmologies
  We study, for the first time, how shear and angular momentum modify typical
parameters of the spherical collapse model, in dark energy dominated universes.
In particular, we study the linear density threshold for collapse
$\delta_\mathrm{c}$ and the virial overdensity $\Delta_\mathrm{V}$, for several
dark-energy models and its influence on the cumulative mass function. The
equations of the spherical collapse are those obtained in Pace et al. (2010),
who used the fully nonlinear differential equation for the evolution of the
density contrast derived from Newtonian hydrodynamics, and assumed that dark
energy is present only at the background level. With the introduction of the
shear and rotation terms, the parameters of the spherical collapse model are
now mass-dependant. The results of the paper show, as expected, that the new
terms considered in the spherical collapse model oppose the collapse of
perturbations on galactic scale giving rise to higher values of the linear
overdensity parameter with respect to the non-rotating case. We find a similar
effect also for the virial overdensity parameter. For what concerns the mass
function, we find that its high mass tail is suppressed, while the low mass
tail is slightly affected except in some cases, e.g. the Chaplygin gas case.
