Bibcode
Lippich, M.; Sánchez, Ariel G.; Colavincenzo, Manuel; Sefusatti, Emiliano; Monaco, Pierluigi; Blot, Linda; Crocce, Martin; Alvarez, Marcelo A.; Agrawal, Aniket; Avila, Santiago; Balaguera-Antolínez, A.; Bond, Richard; Codis, Sandrine; Dalla Vecchia, C.; Dorta, A.; Fosalba, Pablo; Izard, Albert; Kitaura, F.-S.; Pellejero-Ibanez, M.; Stein, George; Vakili, Mohammadjavad; Yepes, Gustavo
Bibliographical reference
Monthly Notices of the Royal Astronomical Society, Volume 482, Issue 2, p.1786-1806
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1
2019
Citations
74
Refereed citations
73
Description
This paper is the first in a set that analyses the covariance matrices
of clustering statistics obtained from several approximate methods for
gravitational structure formation. We focus here on the covariance
matrices of anisotropic two-point correlation function measurements. Our
comparison includes seven approximate methods, which can be divided into
three categories: predictive methods that follow the evolution of the
linear density field deterministically (ICE-COLA, PEAK PATCH, and
PINOCCHIO), methods that require a calibration with N-body simulations
(PATCHY and HALOGEN), and simpler recipes based on assumptions regarding
the shape of the probability distribution function (PDF) of density
fluctuations (lognormal and Gaussian density fields). We analyse the
impact of using covariance estimates obtained from these approximate
methods on cosmological analyses of galaxy clustering measurements,
using as a reference the covariances inferred from a set of full N-body
simulations. We find that all approximate methods can accurately recover
the mean parameter values inferred using the N-body covariances. The
obtained parameter uncertainties typically agree with the corresponding
N-body results within 5 per cent for our lower mass threshold and 10 per
cent for our higher mass threshold. Furthermore, we find that the
constraints for some methods can differ by up to 20 per cent depending
on whether the halo samples used to define the covariance matrices are
defined by matching the mass, number density, or clustering amplitude of
the parent N-body samples. The results of our configuration-space
analysis indicate that most approximate methods provide similar results,
with no single method clearly outperforming the others.
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