We present a public code to generate random fields with an arbitrary probability distribution function (PDF) and an arbitrary correlation function. The algorithm is cosmology independent and applicable to any stationary stochastic process over a three-dimensional grid. We implement it in the case of the matter density field, showing its benefits over the lognormal approximation, which is often used in cosmology for the generation of mock catalogues. We find that the covariance of the power spectrum from the new fast realizations is more accurate than that from a lognormal model. As a proof of concept, we also apply the new simulation scheme to the divergence of the Lagrangian displacement field. We find that information from the correlation function and the PDF of the displacement-divergence provides modest improvement over other standard analytical techniques to describe the particle field in the simulation. This suggests that further progress in this direction should come from multiscale or non-local properties of the initial matter distribution.

Beyond the lognormal approximation: a general simulation scheme / F. Tosone, M.C. Neyrinck, B.R. Granett, L. Guzzo, N. Vittorio. - In: MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY. - ISSN 0035-8711. - 498:2(2020 Oct), pp. 2663-2675.

Beyond the lognormal approximation: a general simulation scheme

B.R. Granett;L. Guzzo
Penultimo
;
2020-10

Abstract

We present a public code to generate random fields with an arbitrary probability distribution function (PDF) and an arbitrary correlation function. The algorithm is cosmology independent and applicable to any stationary stochastic process over a three-dimensional grid. We implement it in the case of the matter density field, showing its benefits over the lognormal approximation, which is often used in cosmology for the generation of mock catalogues. We find that the covariance of the power spectrum from the new fast realizations is more accurate than that from a lognormal model. As a proof of concept, we also apply the new simulation scheme to the divergence of the Lagrangian displacement field. We find that information from the correlation function and the PDF of the displacement-divergence provides modest improvement over other standard analytical techniques to describe the particle field in the simulation. This suggests that further progress in this direction should come from multiscale or non-local properties of the initial matter distribution.
large-scale structure of Universe; cosmology: theory;
Settore FIS/05 - Astronomia e Astrofisica
Attività di studio per la comunità scientifica di Cosmologia
Cosmology and Fundamental Physics: illuminating the Dark Universe with Euclid
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/2434/777034
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