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Forthcoming high-resolution observations of the Cosmic Microwave Background (CMB) radiation will generate datasets many orders of magnitude larger than have been obtained to date. The size and complexity of such datasets presents a very…

Astrophysics · Physics 2016-08-25 Julian Borrill

We investigate the extent to which foreground cleaned CMB maps can be used to estimate the cosmological parameters at small scales. We use the SMICA method, a blind separation technique which works directly at the spectral level. In this…

Cosmology and Nongalactic Astrophysics · Physics 2019-04-17 C. Umiltà , J. F. Cardoso , K. Benabed , M. Le Jeune

We use an iterative generalized least squares map-making algorithm, in conjunction with Monte Carlo techniques, to obtain estimates of the angular power spectrum from cosmic microwave background (CMB) maps. This is achieved by…

Astrophysics · Physics 2009-11-07 A. Balbi , G. de Gasperis , P. Natoli , N. Vittorio

In recent years the goal of estimating different cosmological parameters precisely has set new challenges in the effort to accurately measure the angular power spectrum of CMB. This has required removal of foreground contamination as well…

Astrophysics · Physics 2008-11-26 Rajib Saha , Simon Prunet , Pankaj Jain , Tarun Souradeep

Cosmological emulators of observables such as the Cosmic Microwave Background (CMB) spectra and matter power spectra commonly use training data sampled from a Latin hypercube. This method often incurs high computational costs by covering…

Cosmology and Nongalactic Astrophysics · Physics 2024-05-03 Andreas Nygaard , Emil Brinch Holm , Steen Hannestad , Thomas Tram

Estimation of the angular power spectrum of the Cosmic Microwave Background (CMB) on a small patch of sky is usually plagued by serious spectral leakage, specially when the map has a hard edge. Even on a full sky map, point source masks can…

Astrophysics · Physics 2009-11-06 Sudeep Das , Amir Hajian , David N. Spergel

We discuss a method of calculating the key cosmological parameters on the basis of a selected scale factor by using exact solutions of the background equations. We specify the formulas for calculating the power spectrum, the spectral…

General Relativity and Quantum Cosmology · Physics 2017-04-19 Sergey V. Chervon , Igor V. Fomin

We present a Bayesian sampling algorithm called adaptive importance sampling or Population Monte Carlo (PMC), whose computational workload is easily parallelizable and thus has the potential to considerably reduce the wall-clock time…

Cosmology and Nongalactic Astrophysics · Physics 2009-09-02 Darren Wraith , Martin Kilbinger , Karim Benabed , Olivier Cappé , Jean-François Cardoso , Gersende Fort , Simon Prunet , Christian P. Robert

Annealing algorithms such as simulated annealing and population annealing are widely used both for sampling the Gibbs distribution and solving optimization problems (i.e. finding ground states). For both statistical mechanics and…

Statistical Mechanics · Physics 2024-05-13 Amin Barzegar , Firas Hamze , Christopher Amey , Jonathan Machta

It is widely believed that maximum likelihood estimators must be used to provide optimal estimates of power spectra. Since such estimators require require of order N_d^3 operations they are computationally prohibitive for N_d greater than a…

Astrophysics · Physics 2008-11-26 G. Efstathiou

We propose two algorithms that use both models and datasets to estimate angular power spectra from channel covariance matrices in massive MIMO systems. The first algorithm is an iterative fixed-point method that solves a hierarchical…

Signal Processing · Electrical Eng. & Systems 2020-12-11 Renato Luis Garrido Cavalcante , Slawomir Stanczak

Fast robust methods for calculating likelihoods from CMB observations on small scales generally rely on approximations based on a set of power spectrum estimators and their covariances. We investigate the optimality of these approximation,…

Cosmology and Nongalactic Astrophysics · Physics 2009-11-06 Samira Hamimeche , Antony Lewis

The estimation of cosmological parameters from precision observables is an important industry with crucial ramifications for particle physics. This article discusses the statistical methods presently used in cosmological data analysis,…

High Energy Physics - Theory · Physics 2009-12-15 Andrew R Liddle

Pruning methods have recently grown in popularity as an effective way to reduce the size and computational complexity of deep neural networks. Large numbers of parameters can be removed from trained models with little discernible loss in…

Machine Learning · Computer Science 2024-01-18 Tim Whitaker , Darrell Whitley

Recovering the polarized cosmic microwave background (CMB) is essential for shedding light on the exponential expansion of the very early Universe, known as cosmic inflation. Achieving this goal requires not only improved instrumental…

Cosmology and Nongalactic Astrophysics · Physics 2025-09-18 J. M. Casas , L. Bonavera , J. González-Nuevo , G. Puglisi , C. Baccigalupi , S. R. Cabo , M. M. Cueli , D. Crespo , C. González-Gutiérrez , F. J. de Cos

We propose a straightforward and model independent methodology for characterizing the sensitivity of CMB and other experiments to wiggles, irregularities, and features in the primordial power spectrum. Assuming that the primordial…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-11 Christopher Gauthier , Martin Bucher

We implement a simple, main beam correction in the maximum-likelihood, parametric component separation approach, which allows on accounting for different beamwidths of input maps at different frequencies without any preprocessing. We…

Cosmology and Nongalactic Astrophysics · Physics 2025-05-19 Arianna Rizzieri , Josquin Errard , Radek Stompor

Over the last decade, measurements of the CMB anisotropy has spearheaded the remarkable transition of cosmology into a precision science. However, addressing the systematic effects in the increasingly sensitive, high resolution, `full' sky…

Astrophysics · Physics 2009-03-31 Sanjit Mitra , Anand S. Sengupta , Subharthi Ray , Rajib Saha , Tarun Souradeep

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

The Cosmic Microwave Background (CMB) is an abundant source of cosmological information. However, this information is encoded in non-trivial ways in a signal that is difficult to observe. The resulting challenges in extracting this…

Astrophysics · Physics 2014-10-13 Benjamin D. Wandelt