[2210.14769] Spherical collapse of non-top-hat profiles in the presence of dark energy with arbitrary sound speed

[Submitted on 26 Oct 2022]

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Abstract: We study the spherical collapse of non-top-hat matter fluctuations in the
presence of dark energy with arbitrary sound speed. The model is described by a
system of partial differential equations solved using a pseudo-spectral method
with collocation points. This method can reproduce the known analytical
solutions in the linear regime with an accuracy better than $10^{-6}\%$ and
better than $10^{-2}\%$ for the virialization threshold given by the usual
spherical collapse model. We show the impact of nonlinear dark energy
fluctuations on matter profiles, matter peculiar velocity and gravitational
potential. We also show that phantom dark energy models with low sound speed
can develop a pathological behaviour around matter halos, namely negative
energy density. The dependence of the virialization threshold density for
collapse on the dark energy sound speed is also computed, confirming and
extending previous results in the limit for homogeneous and clustering dark
energy.