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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

The estimation of cosmological parameters from cosmic microwave experiments has almost always been performed assuming gaussian data. In this paper the sensitivity of the parameter estimation to different assumptions on the probability…

Astrophysics · Physics 2009-11-07 Luca Amendola

Most cosmological parameter estimations are based on the same set of observations and are therefore not independent. Here, we test the consistency of parameter estimations using a combination of large-scale structure and supernovae data,…

Astrophysics · Physics 2009-11-10 Carolina Odman , Mike Hobson , Anthony Lasenby , Alessandro Melchiorri

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

A comparison of the standard models in particle physics and in cosmology demonstrates that they are not compatible, though both are well established. Basics of modern cosmology are briefly reviewed. It is argued that the measurements of the…

High Energy Physics - Phenomenology · Physics 2008-11-26 A. D. Dolgov

The majority of present efforts to constrain cosmological parameters with cosmic microwave background (CMB) anisotropy data employ approximate likelihood functions, the time consuming nature of a complete analysis being a major obstacle. We…

Astrophysics · Physics 2007-05-23 M. Douspis , J. G. Bartlett , A. Blanchard , M. Le Dour

Upcoming cosmological surveys will achieve increasingly precise constraints in cosmological parameter estimation. To guarantee the robustness of cosmological analyses, it is essential to account for and model systematic effects that can…

Cosmology and Nongalactic Astrophysics · Physics 2026-04-20 Biancamaria Sersante , Christos Georgiou , Nora Elisa Chisari

We study the impact of assumptions made about the neutrino mass ordering on cosmological parameter estimation with the purpose of understanding whether in the future it will be possible to infer the specific neutrino mass distribution from…

Cosmology and Nongalactic Astrophysics · Physics 2020-09-15 Maria Archidiacono , Steen Hannestad , Julien Lesgourgues

Abstract Covariance matrix estimation is a challenging problem in cosmology. Recent work has shown that model covariance matrices can be precise, and that at relatively large scales they can also be accurate. We introduce a data-driven…

Cosmology and Nongalactic Astrophysics · Physics 2019-11-13 Ross O'Connell

One of the main challenges facing upcoming CMB experiments will be to distinguish the cosmological signal from foreground contamination. We present a comprehensive treatment of this problem and study how foregrounds degrade the accuracy…

Astrophysics · Physics 2009-10-07 Max Tegmark , Daniel J. Eisenstein , Wayne Hu , Angelica de Oliveira-Costa

With the increased accuracy and angular scale coverage of the recent CMB experiments it has become important to include calibration and beam uncertainties when estimating cosmological parameters. This requires an integration over possible…

Astrophysics · Physics 2009-11-07 S. L. Bridle , R. Crittenden , A. Melchiorri , M. P. Hobson , R. Kneissl , A. N. Lasenby

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

We study the impact of the cosmological parameters uncertainties on the measurements of primordial non-Gaussianity through the large-scale non-Gaussian halo bias effect. While this is not expected to be an issue for the standard LCDM model,…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-13 Carmelita Carbone , Olga Mena , Licia Verde

We describe a statistical model to estimate the covariance matrix of matter tracer two-point correlation functions with cosmological simulations. Assuming a fixed number of cosmological simulation runs, we describe how to build a…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-15 Christopher B. Morrison , Michael D. Schneider

[Abridged] We seek approximations to the cosmic shear covariance that are as easy to use as the common approximations based on normal statistics, but yield more accurate covariance matrices and parameter errors. We derive expressions for…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-28 Stefan Hilbert , Jan Hartlap , Peter Schneider

Constraints on cosmological parameters depend on the set of parameters chosen to define the model which is compared with observational data. I use the Akaike and Bayesian information criteria to carry out cosmological model selection, in…

Astrophysics · Physics 2009-11-10 Andrew R. Liddle

With the advent of large-scale weak lensing surveys there is a need to understand how realistic, scale-dependent systematics bias cosmic shear and dark energy measurements, and how they can be removed. Here we describe how spatial…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-31 A. N. Taylor , T. D. Kitching

Anomalies drive scientific discovery -- they are associated with the cutting edge of the research frontier, and thus typically exploit data in the low signal-to-noise regime. In astronomy, the prevalence of systematics --- both "known…

Cosmology and Nongalactic Astrophysics · Physics 2014-10-16 Hiranya V. Peiris

Given a standard model to test, an experiment can be designed to: (i) measure the standard model parameters; (ii) extend the standard model; or (iii) look for evidence of deviations from the standard model. To measure (or extend) the…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 Adam Amara , Thomas Kitching

The averaging problem in cosmology is of considerable importance for the correct interpretation of cosmological data. We review cosmological observations and discuss some of the issues regarding averaging. We present a precise definition of…

Cosmology and Nongalactic Astrophysics · Physics 2010-01-07 Alan Coley