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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

Upcoming galaxy surveys will allow us to probe the growth of the cosmic large-scale structure with improved sensitivity compared to current missions, and will also map larger areas of the sky. This means that in addition to the increased…

Cosmology and Nongalactic Astrophysics · Physics 2022-01-31 Matteo Martinelli , Roohi Dalal , Fereshteh Majidi , Yashar Akrami , Stefano Camera , Elena Sellentin

The interpretation of cosmological observables requires the use of increasingly sophisticated theoretical models. Since these models are becoming computationally very expensive and display non-trivial uncertainties, the use of standard…

Cosmology and Nongalactic Astrophysics · Physics 2020-10-14 Marcos Pellejero-Ibañez , Raul E. Angulo , Giovanni Aricó , Matteo Zennaro , Sergio Contreras , Jens Stücker

Although the broad outlines of the appropriate pipeline for cosmological likelihood analysis with CMB data has been known for several years, only recently have we had to contend with the full, large-scale, computationally challenging…

Astrophysics · Physics 2009-11-10 Andrew H. Jaffe , J. R. Bond , P. G. Ferreira , L. E. Knox

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

Several cosmological measurements have attained significant levels of maturity and accuracy over the last decade. Continuing this trend, future observations promise measurements of the statistics of the cosmic mass distribution at an…

Astrophysics · Physics 2008-11-26 Salman Habib , Katrin Heitmann , David Higdon , Charles Nakhleh , Brian Williams

The estimation of cosmological parameters from a given data set requires a construction of a likelihood function which, in general, has a complicated functional form. We adopt a Gaussian copula and constructed a copula likelihood function…

Cosmology and Nongalactic Astrophysics · Physics 2010-12-28 Masanori Sato , Kiyotomo Ichiki , Tsutomu T. Takeuchi

In the near future, observations of the cosmic microwave background (CMB) anisotropies will provide accurate determinations of many fundamental cosmological parameters. In this paper, we analyse degeneracies among cosmological parameters to…

Astrophysics · Physics 2009-10-30 G. Efstathiou , J. R. Bond

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

In these lectures I cover a number of topics in cosmological data analysis. I concentrate on general techniques which are common in cosmology, or techniques which have been developed in a cosmological context. In fact they have very general…

Cosmology and Nongalactic Astrophysics · Physics 2010-06-08 Alan Heavens

The primary science driver for 3D galaxy surveys is their potential to constrain cosmological parameters. Forecasts of these surveys' effectiveness typically assume Gaussian statistics for the underlying matter density, despite the fact…

Cosmology and Nongalactic Astrophysics · Physics 2015-10-27 Andrew Repp , István Szapudi , Julien Carron , Melody Wolk

We test the effects of varying the cosmological parameter values used in the strong lens modeling process for the six Hubble Frontier Fields (HFF) galaxy clusters. The standard procedure for generating high fidelity strong lens models…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-27 Matthew B. Bayliss , Keren Sharon , Traci Johnson

We study how well the Gaussian approximation is valid for computing the covariance matrices of the convergence power and bispectrum in weak gravitational lensing analyses. We focus on its impact on the cosmological parameter estimations by…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-12 Masanori Sato , Takahiro Nishimichi

When inferring parameters from a Gaussian-distributed data set by computing a likelihood, a covariance matrix is needed that describes the data errors and their correlations. If the covariance matrix is not known a priori, it may be…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-27 Elena Sellentin , Alan F. Heavens

We use analytic covariance matrices to carry out a full-shape analysis of the galaxy power spectrum multipoles from the Baryon Oscillation Spectroscopic Survey (BOSS). We obtain parameter estimates that agree well with those based on the…

Cosmology and Nongalactic Astrophysics · Physics 2020-12-29 Digvijay Wadekar , Mikhail M. Ivanov , Roman Scoccimarro

The advent of Stage IV weak lensing surveys will open up a new era in precision cosmology. These experiments will offer more than an order-of-magnitude leap in precision over existing surveys, and we must ensure that the accuracy of our…

Cosmology and Nongalactic Astrophysics · Physics 2021-06-09 Anurag C. Deshpande , Thomas D. Kitching

Cosmological parameter estimation is entering a new era. Large collaborations need to coordinate high-stakes analyses using multiple methods; furthermore such analyses have grown in complexity due to sophisticated models of cosmology and…

Cosmology and Nongalactic Astrophysics · Physics 2018-04-04 Joe Zuntz , Marc Paterno , Elise Jennings , Douglas Rudd , Alessandro Manzotti , Scott Dodelson , Sarah Bridle , Saba Sehrish , James Kowalkowski

A method is presented for performing joint analyses of cosmological datasets, in which the weight assigned to each dataset is determined directly by it own statistical properties. The weights are considered in a Bayesian context as a set of…

Astrophysics · Physics 2009-11-07 M. P. Hobson , S. L. Bridle , O. Lahav

Cosmological observables rely heavily on summary statistics such as two-point correlation functions. In many practical cases (e.g. the weak-lensing cosmic shear), those correlation functions are estimated from a finite, discrete sample of…

Cosmology and Nongalactic Astrophysics · Physics 2025-06-24 Pierre Fleury

The complexity and accuracy of current and future precision cosmology observational campaigns has made it essential to develop an efficient technique for directly combining simulation and observational datasets to determine cosmological and…

Astrophysics · Physics 2009-11-11 Katrin Heitmann , David Higdon , Charles Nakhleh , Salman Habib