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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…

Instrumentation and Methods for Astrophysics · Physics 2017-12-06 Oliver Friedrich , Tim Eifler

Data analysis from upcoming large galaxy redshift surveys, such as Euclid and DESI will significantly improve constraints on cosmological parameters. To optimally extract the information from these galaxy surveys, it is important to control…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-22 S. Gouyou Beauchamps , P. Baratta , S. Escoffier , W. Gillard , J. Bel , J. Bautista , C. Carbone

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…

Cosmology and Nongalactic Astrophysics · Physics 2022-05-31 Tassia Ferreira , Valerio Marra

Data analysis in cosmology requires reliable covariance matrices. Covariance matrices derived from numerical simulations often require a very large number of realizations to be accurate. When a theoretical model for the covariance matrix…

Cosmology and Nongalactic Astrophysics · Physics 2022-12-21 Alessandra Fumagalli , Matteo Biagetti , Alexandro Saro , Emiliano Sefusatti , Anže Slosar , Pierluigi Monaco , Alfonso Veropalumbo

In this work, we reconstruct the H(z) based on observational Hubble data with Artificial Neural Network, then estimate the cosmological parameters and the Hubble constant. The training data we used are covariance matrix and mock H(z), which…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-23 Jie-feng Chen , Tong-Jie Zhang , Peng He , Tingting Zhang , Jie Zhang

We propose a lightweight deep convolutional neural network (lCNN) to estimate cosmological parameters from simulated three-dimensional dark matter (DM) halo distributions and associated statistics. The training dataset comprises 2000…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-20 Zhiwei Min , Xu Xiao , Jiacheng Ding , Liang Xiao , Jie Jiang , Donglin Wu , Qiufan Lin , Yang Wang , Shuai Liu , Zhixin Chen , Xiangru Li , Jinqu Zhang , Le Zhang , Xiao-Dong Li

The likelihood function for cosmological parameters, given by e.g. weak lensing shear measurements, depends on contributions to the covariance induced by the nonlinear evolution of the cosmic web. As nonlinear clustering to date has only…

Cosmology and Nongalactic Astrophysics · Physics 2019-02-26 Robert Reischke , Alina Kiessling , Björn Malte Schäfer

Statistical analysis of massive datasets very often implies expensive linear algebra operations with large dense matrices. Typical tasks are an estimation of unknown parameters of the underlying statistical model and prediction of missing…

Computation · Statistics 2021-04-16 Alexander Litvinenko , Ronald Kriemann , Vladimir Berikov

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…

Instrumentation and Methods for Astrophysics · Physics 2017-01-11 Benjamin Joachimi

Focusing on the well motivated aperture mass statistics $\Map$, we study the possibility of constraining cosmological parameters using future space based SNAP class weak lensing missions. Using completely analytical results we construct the…

Astrophysics · Physics 2007-05-23 Dipak Munshi , Patrick Valageas

Creating accurate and low-noise covariance matrices represents a formidable challenge in modern-day cosmology. We present a formalism to compress arbitrary observables into a small number of bins by projection into a model-specific subspace…

Cosmology and Nongalactic Astrophysics · Physics 2021-02-10 Oliver H. E. Philcox , Mikhail M. Ivanov , Matias Zaldarriaga , Marko Simonovic , Marcel Schmittfull

The high accuracy of detector simulation is crucial for modern particle physics experiments. However, this accuracy comes with a high computational cost, which will be exacerbated by the large datasets and complex detector upgrades…

Accurate and precise covariance matrices will be important in enabling planned cosmological surveys to detect new physics. Standard methods imply either the need for many N-body simulations in order to obtain an accurate estimate, or a…

Cosmology and Nongalactic Astrophysics · Physics 2018-12-13 Alex Hall , Andy Taylor

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

Mammography is using low-energy X-rays to screen the human breast and is utilized by radiologists to detect breast cancer. Typically radiologists require a mammogram with impeccable image quality for an accurate diagnosis. In this study, we…

Image and Video Processing · Electrical Eng. & Systems 2019-12-12 Dominik Eckert , Sulaiman Vesal , Ludwig Ritschl , Steffen Kappler , Andreas Maier

Extracting parameter constraints from cosmological observations requires accurate determination of the covariance matrix for use in the likelihood function. We show here that uncertainties in the elements of the covariance matrix propagate…

Cosmology and Nongalactic Astrophysics · Physics 2013-10-30 Scott Dodelson , Michael D. Schneider

Magnetic particle imaging reconstructs tracer distributions using a system matrix obtained through time-consuming, noise-prone calibration measurements. Methods for addressing imperfections in measured system matrices increasingly rely on…

Image and Video Processing · Electrical Eng. & Systems 2026-03-20 Artyom Tsanda , Sarah Reiss , Konrad Scheffler , Marija Boberg , Tobias Knopp

High-resolution cosmological N-body simulations are excellent tools for modelling the formation and clustering of dark matter haloes. These simulations suggest complex physical theories of halo formation governed by a set of effective…

Cosmology and Nongalactic Astrophysics · Physics 2022-06-24 Androniki Dimitriou , Christoph Weniger , Camila A. Correa

In recent years, deep learning models have been successfully employed for augmenting low-resolution cosmological simulations with small-scale information, a task known as "super-resolution". So far, these cosmological super-resolution…

Cosmology and Nongalactic Astrophysics · Physics 2024-11-14 Andreas Schanz , Florian List , Oliver Hahn

Computed tomography is widely used as an imaging tool to visualize three-dimensional structures with expressive bone-soft tissue contrast. However, CT resolution and radiation dose are tightly entangled, highlighting the importance of…

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