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Cosmic voids are large underdense regions that, together with galaxy clusters, filaments and walls, build up the large-scale structure of the Universe. The void size function provides a powerful probe to test the cosmological framework.…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-08 Sofia Contarini , Tommaso Ronconi , Federico Marulli , Lauro Moscardini , Alfonso Veropalumbo , Marco Baldi

Multivariate spatial-statistical models are often used when modeling environmental and socio-demographic processes. The most commonly used models for multivariate spatial covariances assume both stationarity and symmetry for the…

Methodology · Statistics 2021-05-11 Quan Vu , Andrew Zammit-Mangion , Noel Cressie

We investigate the impact of different observational effects affecting a precise and accurate measurement of the growth rate of fluctuations from the anisotropy of clustering in galaxy redshift surveys. We focus on redshift measurement…

Cosmology and Nongalactic Astrophysics · Physics 2012-10-23 Federico Marulli , Davide Bianchi , Enzo Branchini , Luigi Guzzo , Lauro Moscardini , Raul E. Angulo

One of the goals in scaling sequential machine learning methods pertains to dealing with high-dimensional data spaces. A key related challenge is that many methods heavily depend on obtaining the inverse covariance matrix of the data. It is…

Computation · Statistics 2017-07-28 Tomer Lancewicki

Redshift space distortion (RSD) observed in galaxy redshift surveys is a powerful tool to test gravity theories on cosmological scales, but the systematic uncertainties must carefully be examined for future surveys with large statistics.…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Takashi Ishikawa , Tomonori Totani , Takahiro Nishimichi , Ryuichi Takahashi , Naoki Yoshida , Motonari Tonegawa

Stage-IV galaxy surveys will measure correlations at small cosmological scales with high signal-to-noise ratio. One of the main challenges of extracting information from small scales is devising accurate models, as well as characterizing…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-20 Abdias Aires , Nickolas Kokron , Rogerio Rosenfeld , Felipe Andrade-Oliveira , Vivian Miranda

Future galaxy surveys hope to distinguish between the dark energy and modified gravity scenarios for the accelerating expansion of the Universe using the distortion of clustering in redshift space. The aim is to model the form and size of…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-06 Elise Jennings , Carlton M. Baugh , Silvia Pascoli

Lagrangian reconstruction of large-scale peculiar velocity fields can be strongly affected by observational biases. We develop a thorough analysis of these systematic effects by relying on specially selected mock catalogues. For the purpose…

Astrophysics · Physics 2009-11-13 G. Lavaux , R. Mohayaee , S. Colombi , R. B. Tully , F. Bernardeau , J. Silk

We propose to use a simple observable, the fractional area of "hot spots" in weak lensing mass maps which are detected with high significance, to determine background cosmological parameters. Because these high-shear regions are directly…

Astrophysics · Physics 2008-09-24 Sheng Wang , Zoltan Haiman , Morgan May , John Kehayias

In relativistic cosmology, the formation of nonlinear inhomogeneities can induce non-negligible backreaction on late-time expansion. Among the important consequences for precision cosmology is the potential impact on the linear growth of…

General Relativity and Quantum Cosmology · Physics 2026-04-27 Marco Galoppo , Pierre Mourier

We tackle covariance estimation in low-sample scenarios, employing a structured covariance matrix with shrinkage methods. These involve convexly combining a low-bias/high-variance empirical estimate with a biased regularization estimator,…

Instrumentation and Methods for Astrophysics · Physics 2024-06-28 Olivier Flasseur , Eric Thiébaut , Loïc Denis , Maud Langlois

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

Data re-sampling methods such as the delete-one jackknife are a common tool for estimating the covariance of large scale structure probes. In this paper we investigate the concepts of internal covariance estimation in the context of cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2017-01-10 O. Friedrich , S. Seitz , T. F. Eifler , D. Gruen

Accurate inference of cosmology from weak lensing shear requires an accurate shear power spectrum covariance matrix. Here, we investigate this accuracy requirement and quantify the relative importance of the Gaussian (G), super-sample…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-20 Alexandre Barreira , Elisabeth Krause , Fabian Schmidt

Recent developments in engineering techniques for spatial data collection such as geographic information systems have resulted in an increasing need for methods to analyze large spatial data sets. These sorts of data sets can be found in…

Methodology · Statistics 2020-08-14 Toshihiro Hirano

Covariance matrices are among the most difficult pieces of end-to-end cosmological analyses. In principle, for two-point functions, each component involves a four-point function, and the resulting covariance often has hundreds of thousands…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-20 Tassia Ferreira , Tianqing Zhang , Nianyi Chen , Scott Dodelson

Extracting accurate cosmological information from galaxy-galaxy and galaxy-matter correlation functions on non-linear scales ($\lesssim 10 h^{-1} \mathrm{Mpc}$) requires cosmological simulations. Additionally, one has to marginalise over…

Cosmology and Nongalactic Astrophysics · Physics 2019-10-02 Johannes U. Lange , Frank C. van den Bosch , Andrew R. Zentner , Kuan Wang , Andrew P. Hearin , Hong Guo

Simulation-based inference (SBI) has become an important tool in cosmology for extracting additional information from observational data using simulations. However, all cosmological simulations are approximations of the actual universe, and…

Cosmology and Nongalactic Astrophysics · Physics 2025-07-08 Sébastien Pierre , Bruno Régaldo-Saint Blancard , ChangHoon Hahn , Michael Eickenberg

Measurements of cosmic flows enable us to test whether cosmological models can accurately describe the evolution of the density field in the nearby Universe. In this paper, we measure the low-order kinematic moments of the cosmic flow…

Cosmology and Nongalactic Astrophysics · Physics 2021-12-01 Fei Qin , David Parkinson , Cullan Howlett , Khaled Said

Forecast verification plays a crucial role in the development cycle of operational numerical weather prediction models. At the same time, verification remains a challenge as the traditionally used non-spatial forecast quality metrics…

Atmospheric and Oceanic Physics · Physics 2026-05-25 Gregor Skok , Katarina Kosovelj