Dynamics of gravitational clustering III. The quasi-linear regime for some non-Gaussian initial conditions

Abstract

Using a non-perturbative method developed in a previous work (paper II), we derive the probability distribution $P({\delta }_R)$ of the density contrast within spherical cells in the quasi-linear regime for some non-Gaussian initial conditions. We describe three such models. The first one is a straightforward generalization of the Gaussian scenario. It can be seen as a phenomenological description of a density field where the tails of the linear density contrast distribution would be of the form $P_L({\delta }_L)\sim e^{-|{\delta }_L{|}^{-\alpha }}$, where $\alpha$ is no longer restricted to 2 (as in the Gaussian case). We derive exact results for $P({\delta }_R)$ in the quasi-linear limit. The second model is a physically motivated isocurvature CDM scenario. Our approach needs to be adapted to this specific case and in order to get convenient analytical results we introduce a simple approximation (which is not related to the gravitational dynamics but to the initial conditions). Then, we find a good agreement with the available results from numerical simulations for the pdf of the linear density contrast for $δ_{L,R} \ga 0$. We can expect a similar accuracy for the non-linear pdf $P({\delta }_R)$. Finally, the third model corresponds to the small deviations from Gaussianity which arise in standard slow-roll inflation. We obtain exact results for the pdf of the density field in the quasi-linear limit, to first-order over the primordial deviations from Gaussianity.

18 pages, final version published in A&A

References in corpus (4)

• Dynamics of gravitational clustering II. Steepest-descent method for the quasi-linear regime
• Dynamics of gravitational clustering I. Building perturbative expansions
• Dynamics of gravitational clustering V. Subleading corrections in the quasi-linear regime
• Dynamics of gravitational clustering IV. The probability distribution of rare events

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• Mass function and bias of dark matter halos for non-Gaussian initial conditions
• Hunting high and low: Disentangling primordial and late-time non-Gaussianity with cosmic densities in spheres
• A Large Deviation Principle at play in Large-Scale Structure cosmology
• Dynamics of gravitational clustering IV. The probability distribution of rare events
• Transients from Zel'dovich initial conditions
• One-point probability distribution function from spherical collapse: Early Dark Energy (EDE) vs. $\Lambda$CDM
• Characteristic Functions for Cosmological Cross-Correlations