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In the era of precision cosmology, establishing the correct magnitude of statistical errors in cosmological parameters is of crucial importance. However, widely used approximations in galaxy surveys analyses can lead to parameter…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-07 Nicola Bellomo , José Luis Bernal , Giulio Scelfo , Alvise Raccanelli , Licia Verde

Weak lensing peak counts are a powerful statistical tool for constraining cosmological parameters. So far, this method has been applied only to surveys with relatively small areas, up to several hundred square degrees. As future surveys…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-01 Janis Fluri , Tomasz Kacprzak , Raphael Sgier , Alexandre Réfrégier , Adam Amara

Cosmological probes pose an inverse problem where the measurement result is obtained through observations, and the objective is to infer values of model parameters which characterize the underlying physical system -- our Universe. Modern…

Instrumentation and Methods for Astrophysics · Physics 2019-05-21 Timur Takhtaganov , Zarija Lukic , Juliane Mueller , Dmitriy Morozov

We present a simple approximation that can speed up the computation of the mode-coupling matrices, which are usually the bottleneck for computing unbiased angular power spectra, as well as their associated covariance matrices, of the cosmic…

Cosmology and Nongalactic Astrophysics · Physics 2021-01-04 Thibaut Louis , Sigurd Naess , Xavier Garrido , Anthony Challinor

In the field of statistical learning and data analysis, estimating precision matrices (i.e., the inverse of covariance matrices) is a critical task, particularly for understanding dependency structures among variables. However, traditional…

Methodology · Statistics 2026-05-15 Zhongfeng Qin , Hao Xu , Wenhao Cui , Wan Tian

In this work we use a template method to extract the scale associated with the Baryon Acoustic Oscillation (BAO) signal in 21cm neutral hydrogen intensity maps. We then forecast the constraints on the standard deviations of cosmological…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-10 Benjamin Ostergaard , André Alencar da Costa , Yu Sang

Cosmological large-scale structure analyses based on two-point correlation functions often assume a Gaussian likelihood function with a fixed covariance matrix. We study the impact on cosmological parameter estimation of ignoring the…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-21 Darsh Kodwani , David Alonso , Pedro Ferreira

Cosmological weak lensing by the large scale structure of the Universe, cosmic shear, is coming of age as a powerful probe of the parameters describing the cosmological model and matter power spectrum. It complements CMB studies, by…

Astrophysics · Physics 2009-11-10 Patrick Simon , Lindsay J. King , Peter Schneider

We present a new method that deals with the uncertainty in matter-clustering in cosmic shear power spectrum analysis that arises mainly due to poorly understood nonlinear baryonic processes on small-scales. We show that the majority of…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 T. D. Kitching , A. N. Taylor

There is growing interest in using 3-dimensional neutral hydrogen mapping with the redshifted 21 cm line as a cosmological probe, as it has been argued to have a greater long-term potential than the cosmic microwave background. However, its…

Astrophysics · Physics 2008-11-26 Yi Mao , Max Tegmark , Matthew McQuinn , Matias Zaldarriaga , Oliver Zahn

This paper presents a systematic literature review focusing on the application of machine learning techniques for deriving observational constraints in cosmology. The goal is to evaluate and synthesize existing research to identify…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-14 Luis Rojas , Sebastián Espinoza , Esteban González , Carlos Maldonado , Fei Luo

We explore a variety of statistics of clusters selected with cosmic shear measurement by utilizing both analytic models and large numerical simulations. We first develop a halo model to predict the abundance and the clustering of weak…

Cosmology and Nongalactic Astrophysics · Physics 2015-09-16 Masato Shirasaki , Takashi Hamana , Naoki Yoshida

Weak-lensing mass-mapping algorithms, which reconstruct the convergence field from galaxy shear measurements, are crucial for extracting higher-order statistics to constrain cosmological parameters. However, only limited research has…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-28 Andreas Tersenov , Lucie Baumont , Jean-Luc Starck , Martin Kilbinger

We investigate the bias and error in estimates of the cosmological parameter covariance matrix, due to sampling or modelling the data covariance matrix, for likelihood width and peak scatter estimators. We show that these estimators do not…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-18 Andy Taylor , Benjamin Joachimi

This paper introduces a subspace method for the estimation of an array covariance matrix. It is shown that when the received signals are uncorrelated, the true array covariance matrices lie in a specific subspace whose dimension is…

Numerical Analysis · Computer Science 2014-11-04 Mostafa Rahmani , George Atia

We present a novel Bayesian model and a corresponding robust, probabilistic calibration procedure for the CORSAIR polarimeter that can be applied to other polarimeters. Our calibration procedure combines existing Mueller matrix…

Solar and Stellar Astrophysics · Physics 2026-05-28 Alan Hsu , Jenna Samra , Steven Tomczyk , Maxim Kramar

We present a simple analytic approximation for the covariance between pre-reconstruction galaxy power spectrum measurements and post-reconstruction two-point correlation functions. This cross-covariance is essential for joint analyses that…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-29 M. Maus , A. Baleato Lizancos , M. White , A. de Mattia , S. Chen

We propose a new method for cosmological parameters extraction using the baryon acoustic oscillation scale as a standard ruler in deep galaxy surveys with photometric determination of redshifts. The method consists in a simple empirical…

Cosmology and Nongalactic Astrophysics · Physics 2011-01-25 E. Sanchez , A. Carnero , J. Garcia-Bellido , E. Gaztanaga , F. de Simoni , M. Crocce , A. Cabre , P. Fosalba , D. Alonso

Cosmological constraints derived from weak lensing (WL) surveys are limited by baryonic effects, which suppress the non-linear matter power spectrum on small scales. By combining WL measurements with data from external tracers of the gas…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-10 Amy Wayland , David Alonso , Matteo Zennaro

With the availability of galaxy distance indicators in weak lensing surveys, lensing tomography can be harnessed to constrain the three-dimensional (3D) matter power spectrum over a range of redshift and physical scale. By combining…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-04 Patrick Simon
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