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Cosmological weak lensing measurements rely on a precise measurement of the shear two-point correlation function (2PCF) along with a deep understanding of systematics that affect it. In this work, we demonstrate a general framework for…

Weak lensing has become a powerful tool for probing the matter distribution in the Universe and constraining cosmological parameters. This paper aims to explore the fast mock generation pipeline to obtain the covariance matrix of the…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-17 Yiming Hu , Yu Yu

Super sample covariance (SSC) is important when estimating covariance matrices using a set of mock catalogues for galaxy surveys. If the underlying cosmological simulations do not include the variation in background parameters appropriate…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-05 Greg Schreiner , Alex Krolewski , Shahab Joudaki , Will J. Percival

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

Estimating covariance parameters for multivariate spatial Gaussian random fields is computationally challenging, as the number of parameters grows rapidly with the number of variables, and likelihood evaluation requires operations of order…

Methodology · Statistics 2026-04-10 Francisco Cuevas-Pacheco , Gabriel Riffo , Xavier Emery

Studying the matter distribution in the universe through the Lyman-$\alpha$ forest allows us to constrain small-scale physics in the high-redshift regime. Spectroscopic quasar surveys are generating increasingly large datasets that require…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-23 Josue De-Santiago , Rafael Gutiérrez-Balboa , Gustavo Niz , Alma X. González-Morales

This article discusses aeroacoustic imaging methods based on correlation measurements in the frequency domain. Standard methods in this field assume that the estimated correlation matrix is superimposed with additive white noise. In this…

Signal Processing · Electrical Eng. & Systems 2020-12-30 Hans-Georg Raumer , Carsten Spehr , Thorsten Hohage , Daniel Ernst

The spectrum and coherency are useful quantities for characterizing the temporal correlations and functional relations within and between point processes. This paper begins with a review of these quantities, their interpretation and how…

Biological Physics · Physics 2007-05-23 M. R. Jarvis , P. P. Mitra

We are presenting in this paper a detailed account of the methods used to compute the three-dimensional two-point galaxy correlation function in the VIMOS-VLT deep survey (VVDS). We investigate how instrumental selection effects and…

The correlation length-scale next to the noise variance are the most used hyperparameters for the Gaussian processes. Typically, stationary covariance functions are used, which are only dependent on the distances between input points and…

Machine Learning · Computer Science 2017-10-30 Kevin Cremanns , Dirk Roos

Empirical estimates of the band power covariance matrix are commonly used in cosmic microwave background (CMB) power spectrum analyses. While this approach easily captures correlations in the data, noise in the resulting covariance estimate…

Cosmology and Nongalactic Astrophysics · Physics 2022-03-14 L. Balkenhol , C. L. Reichardt

The covariance matrix of measurements of Markov random fields (processes) has useful properties that allow to develop effective computational algorithms for many problems in the study of Markov fields on the basis of field observations…

Information Theory · Computer Science 2018-04-04 Ulan N. Brimkulov , Chinara Jumabaeva , Kasym Baryktabasov

We present an algorithm for quickly generating multiple realizations of N-body simulations to be used, for example, for cosmological parameter estimation from surveys of large-scale structure. Our algorithm uses a new method to resample the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-27 Michael D. Schneider , Shaun Cole , Carlos S. Frenk , Istvan Szapudi

We study correlation functions of scalar operators on the boundary of the $AdS_3$ space deformed by moving massive particles in the context of the AdS/CFT duality. To calculate two-point correlation functions we use the geodesic…

High Energy Physics - Theory · Physics 2016-12-15 D. S. Ageev , I. Ya. Aref'eva , M. D. Tikhanovskaya

We propose a method to estimate non-Gaussian error bars on the matter power spectrum from galaxy surveys in the presence of non-trivial survey selection functions. The estimators are often obtained from formalisms like FKP and PKL, which…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-30 Joachim Harnois-Deraps , Ue-Li Pen

We present high signal-to-noise measurements of three-point shear correlations and the third moment of the mass aperture statistic using the first 3 years of data from the Dark Energy Survey. We additionally obtain the first measurements of…

The semivarying coefficient models are widely used in the application of finance, economics, medical science and many other areas. The functional coefficients are commonly estimated by local smoothing methods, e.g. local linear estimator.…

Methodology · Statistics 2020-01-01 Heng Peng , Chuanlong Xie , Jingxin Zhao

We present new measurements of the redshift-space three-point correlation function (3PCF) of Luminous Red Galaxies (LRGs) from the Sloan Digital Sky Survey (SDSS). Using the largest dataset to date, the Data Release 7 (DR7) LRGs, and an…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Felipe Marin

Data from the ongoing \textit{Euclid} survey will map out billions of galaxies in the Universe, covering more than a third of the sky. This data will provide a wealth of information about the large-scale structure (LSS) of the Universe and…

Cosmology and Nongalactic Astrophysics · Physics 2025-04-23 Vetle A. Vikenes , Cheng-Zong Ruan , David F. Mota

In this article, we propose a new method for calculating the mixed correlation coefficient (Pearson, polyserial and polychoric) matrix and its covariance matrix based on the GMM framework. We build moment equations for each coefficient and…

Computation · Statistics 2024-04-11 Ben Liu , Peng Zhang , Yi Feng , Xiaowei Lou