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We perform a detailed analysis of the covariance matrix of the spherically averaged galaxy power spectrum and present a new, practical method for estimating this within an arbitrary survey without the need for running mock galaxy…

Cosmology and Nongalactic Astrophysics · Physics 2017-10-18 Cullan Howlett , Will J. Percival

We compute the covariance of the galaxy power spectrum multipoles in perturbation theory, including the effects of nonlinear evolution, nonlinear and nonlocal bias, radial redshift-space distortions, arbitrary survey window and shot noise.…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-08 Digvijay Wadekar , Roman Scoccimarro

We study how well the Gaussian approximation is valid for computing the covariance matrices of the convergence power and bispectrum in weak gravitational lensing analyses. We focus on its impact on the cosmological parameter estimations by…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Masanori Sato , Takahiro Nishimichi

Reliable extraction of cosmological information from clustering measurements of galaxy surveys requires estimation of the error covariance matrices of observables. The accuracy of covariance matrices is limited by our ability to generate…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-29 Mohammadjavad Vakili , Francisco-Shu Kitaura , Yu Feng , Gustavo Yepes , Cheng Zhao , Chia-Hsun Chuang , ChangHoon Hahn

We developed a modification to the calculation of the two-point correlation function commonly used in the analysis of large scale structure in cosmology. An estimator of the two-point correlation function is constructed by contrasting the…

Cosmology and Nongalactic Astrophysics · Physics 2017-12-20 Regina Demina , Sanha Cheong , Segev BenZvi , Otto Hindrichs

We develop a method to simulate galaxy-galaxy weak lensing by utilizing all-sky, light-cone simulations and their inherent halo catalogs. Using the mock catalog to study the error covariance matrix of galaxy-galaxy weak lensing, we compare…

Cosmology and Nongalactic Astrophysics · Physics 2017-07-26 Masato Shirasaki , Masahiro Takada , Hironao Miyatake , Ryuichi Takahashi , Takashi Hamana , Takahiro Nishimichi , Ryoma Murata

We present efficient algorithms for computing the $N$-point correlation functions (NPCFs) of random fields in arbitrary $D$-dimensional homogeneous and isotropic spaces. Such statistics appear throughout the physical sciences, and provide a…

Instrumentation and Methods for Astrophysics · Physics 2022-09-14 Oliver H. E. Philcox , Zachary Slepian

To make use of clustering statistics from large cosmological surveys, accurate and precise covariance matrices are needed. We present a new code to estimate large scale galaxy two-point correlation function (2PCF) covariances in arbitrary…

Cosmology and Nongalactic Astrophysics · Physics 2020-01-08 Oliver H. E. Philcox , Daniel J. Eisenstein , Ross O'Connell , Alexander Wiegand

We present an algorithm enabling computation of the anisotropic redshift-space galaxy 3-point correlation function (3PCF) scaling as $N^2$, with $N$ the number of galaxies. Our previous work showed how to compute the isotropic 3PCF with…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-16 Zachary Slepian , Daniel J. Eisenstein

We calculate the two-, three- and (for the first time) four-point correlation functions of the COBE-DMR 4-year sky maps, and search for evidence of non-Gaussianity by comparing the data to Monte Carlo-simulations of the functions. The…

Astrophysics · Physics 2009-11-07 H. K. Eriksen , A. J. Banday , K. M. Gorski

Upcoming and existing large-scale surveys of galaxies require accurate theoretical predictions of the dark matter clustering statistics for thousands of mock galaxy catalogs. We demonstrate that this goal can be achieve with our new…

Cosmology and Nongalactic Astrophysics · Physics 2018-06-13 Anatoly Klypin , Francisco Prada

We present an approach for accurate estimation of the covariance of 2-point correlation functions that requires fewer mocks than the standard mock-based covariance. This can be achieved by dividing a set of mocks into jackknife regions and…

We present an algorithm that computes the multipole coefficients of the galaxy three-point correlation function (3PCF) without explicitly considering triplets of galaxies. Rather, centering on each galaxy in the survey, it expands the…

Cosmology and Nongalactic Astrophysics · Physics 2015-11-04 Zachary Slepian , Daniel J. Eisenstein

We present a comparison of major methodologies of fast generating mock halo or galaxy catalogues. The comparison is done for two-point and the three-point clustering statistics. The reference catalogues are drawn from the BigMultiDark…

We study the covariance properties of real space correlation function estimators -- primarily galaxy-shear correlations, or galaxy-galaxy lensing -- using SDSS data for both shear catalogs and lenses (specifically the BOSS LOWZ sample).…

Cosmology and Nongalactic Astrophysics · Physics 2017-08-30 Sukhdeep Singh , Rachel Mandelbaum , Uroš Seljak , Anže Slosar , Jose Vazquez Gonzalez

Most statistical inference from cosmic large-scale structure relies on two-point statistics, i.e.\ on the galaxy-galaxy correlation function (2PCF) or the power spectrum. These statistics capture the full information encoded in the Fourier…

Cosmology and Nongalactic Astrophysics · Physics 2023-06-09 Kamran Ali , Danail Obreschkow , Cullan Howlett , Camille Bonvin , Claudio Llinares , Felipe Oliveira Franco , Chris Power

The covariance matrix of the matter power spectrum is a key element of the statistical analysis of galaxy clustering data. Independent realisations of observational measurements can be used to sample the covariance, nevertheless statistical…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-14 Linda Blot , Pier Stefano Corasaniti , Luca Amendola , Thomas D. Kitching

The non-Gaussian part of the covariance matrix of the galaxy power spectrum involves the connected four-point correlation in Fourier space, i.e. trispectrum. This paper introduces a fast method to compute the non-Gaussian part of the…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-07 Yosuke Kobayashi

We present the Mock Map Facility, a powerful tool to generate mock catalogues or images from semi-analytically post-processed snapshots of cosmological N-body simulations. The paper describes in detail an efficient technique to create such…

(shortened) We develop and test a method to compute mass and auto-correlation functions of rich clusters of galaxies from linear density fluctuations, based on the formalism of Gaussian peaks (Bardeen et al 1986). The essential, new…

Astrophysics · Physics 2009-10-30 Renyue Cen