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We describe the construction of an N-body simulation that mimics the true velocity and mass-density fields in a box of side 256\hmpc about the Local Group , and the production of mock catalogs that mimic in detail current catalogs of…

天体物理学 · 物理学 2009-10-28 Tsafrir Kolatt , Avishai Dekel , Galit Ganon , Jeffrey Willick

This article is the second in a series in which we perform an extensive comparison of various galaxy-based cluster mass estimation techniques that utilise the positions, velocities and colours of galaxies. Our aim is to quantify the…

We train neural networks to quickly generate redshift-space galaxy power spectrum covariances from a given parameter set (cosmology and galaxy bias). This covariance emulator utilizes a combination of traditional fully-connected network…

宇宙学与河外天体物理 · 物理学 2024-05-02 Joseph Adamo , Hung-Jin Huang , Tim Eifler

Modern statistical analysis often encounters datasets with large sizes. For these datasets, conventional estimation methods can hardly be used immediately because practitioners often suffer from limited computational resources. In most…

统计方法学 · 统计学 2023-04-14 Shuyuan Wu , Xuening Zhu , Hansheng Wang

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…

宇宙学与河外天体物理 · 物理学 2025-03-05 Greg Schreiner , Alex Krolewski , Shahab Joudaki , Will J. Percival

The Canonical Polyadic (CP) tensor decomposition is frequently used as a model in applications in a variety of different fields. Using jackknife resampling to estimate parameter uncertainties is often desirable but results in an increase of…

数学软件 · 计算机科学 2022-04-14 Christos Psarras , Lars Karlsson , Rasmus Bro , Paolo Bientinesi

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…

宇宙学与河外天体物理 · 物理学 2017-10-18 Cullan Howlett , Will J. Percival

We give an analytical interpretation of how subsample-based internal covariance estimators lead to biased estimates of the covariance, due to underestimating the super-sample covariance (SSC). This includes the jackknife and bootstrap…

宇宙学与河外天体物理 · 物理学 2018-04-16 Fabien Lacasa , Martin Kunz

In many astrophysical settings covariance matrices of large datasets have to be determined empirically from a finite number of mock realisations. The resulting noise degrades inference and precludes it completely if there are fewer…

天体物理仪器与方法 · 物理学 2017-01-11 Benjamin Joachimi

Covariance matrices are important tools for obtaining reliable parameter constraints. Advancements in cosmological surveys lead to larger data vectors and, consequently, increasingly complex covariance matrices, whose number of elements…

宇宙学与河外天体物理 · 物理学 2022-05-31 Tassia Ferreira , Valerio Marra

We apply an iterative reconstruction method to galaxy mocks in redshift space obtained from $N$-body simulations. Comparing the two-point correlation functions for the reconstructed density field, we find that although the performance is…

宇宙学与河外天体物理 · 物理学 2019-06-26 Ryuichiro Hada , Daniel J. Eisenstein

Relying on recent advances in statistical estimation of covariance distances based on random matrix theory, this article proposes an improved covariance and precision matrix estimation for a wide family of metrics. The method is shown to…

机器学习 · 统计学 2021-02-03 Malik Tiomoko , Florent Bouchard , Guillaume Ginholac , Romain Couillet

Next-generation optical imaging surveys will revolutionise the observations of weak gravitational lensing by galaxy clusters and provide stringent constraints on growth of structure and cosmic acceleration. In these experiments, accurate…

宇宙学与河外天体物理 · 物理学 2019-10-17 Hao-Yi Wu , David H. Weinberg , Andrés N. Salcedo , Benjamin D. Wibking , Ying Zu

This work proposes a method to accelerate the acquisition of high-quality edited magnetic resonance spectroscopy (MRS) scans using machine learning models taking the sample covariance matrix as input. The method is invariant to the number…

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…

宇宙学与河外天体物理 · 物理学 2025-06-17 Yiming Hu , Yu Yu

This article presents a new method to compute matrices from numerical simulations based on the ideas of sparse sampling and compressed sensing. The method is useful for problems where the determination of the entries of a matrix constitutes…

化学物理 · 物理学 2014-10-21 Jacob N. Sanders , Xavier Andrade , Alán Aspuru-Guzik

Computing the inverse covariance matrix (or precision matrix) of large data vectors is crucial in weak lensing (and multi-probe) analyses of the large scale structure of the universe. Analytically computed covariances are noise-free and…

天体物理仪器与方法 · 物理学 2017-12-06 Oliver Friedrich , Tim Eifler

We apply two compression methods to the galaxy power spectrum monopole/quadrupole and bispectrum monopole measurements from the BOSS DR12 CMASS sample. Both methods reduce the dimension of the original data-vector to the number of…

宇宙学与河外天体物理 · 物理学 2019-01-07 Davide Gualdi , Héctor Gil-Marín , Robert L. Schuhmann , Marc Manera , Benjamin Joachimi , Ofer Lahav

We present a novel application of cosmological rescaling, or "remapping," to generate 21 cm intensity mapping mocks for different cosmologies. The remapping method allows for computationally efficient generation of N-body catalogs by…

The paper illustrates an application of the Resampling approach [2] for the estimation of the aircraft circulation plan reliability. Resampling is an intensive computer statistical method, which can be used effectively in the case of small…

应用统计 · 统计学 2013-05-14 Maxim Fioshin