English
Related papers

Related papers: Normal Parameters for an Analytic Description of t…

200 papers

The background photon temperature $\bar T$ is one of the fundamental cosmological parameters. Despite its significance, $\bar T$ has never been allowed to vary in the data analysis, owing to the precise measurement of the comic microwave…

Cosmology and Nongalactic Astrophysics · Physics 2019-09-18 Jaiyul Yoo , Ermis Mitsou , Yves Dirian , Ruth Durrer

Observations of large scale structure (LSS) and the Cosmic Microwave Background (CMB) each place separate constraints on the values of cosmological parameters. We calculate a joint likelihood based on various CMB experiments and the IRAS…

Astrophysics · Physics 2007-05-23 Matthew Webster , S. L. Bridle , M. P. Hobson , A. N. Lasenby , Ofer Lahav , Graca Rocha

In this work, we present a new method to estimate cosmological parameters accurately based on the artificial neural network (ANN), and a code called ECoPANN (Estimating Cosmological Parameters with ANN) is developed to achieve parameter…

Cosmology and Nongalactic Astrophysics · Physics 2022-04-29 Guo-Jian Wang , Si-Yao Li , Jun-Qing Xia

As the Cosmic Microwave Background (CMB) radiation is observed to higher and higher angular resolution the size of the resulting datasets becomes a serious constraint on their analysis. In particular current algorithms to determine the…

Astrophysics · Physics 2007-05-23 Julian Borrill

The last years have been an exciting period for the field of the Cosmic Microwave Background (CMB) research. With recent CMB balloon-borne and ground-based experiments we are entering a new era of 'precision' cosmology that enables us to…

Astrophysics · Physics 2007-05-23 Alessandro Melchiorri

Many common loss functions such as mean-squared-error, cross-entropy, and reconstruction loss are unnecessarily rigid. Under a probabilistic interpretation, these common losses correspond to distributions with fixed shapes and scales. We…

Machine Learning · Computer Science 2020-10-05 Mark Hamilton , Evan Shelhamer , William T. Freeman

We present a Markov Chain Monte Carlo (MCMC)-based parameter estimation package, CosmoReionMC, to jointly constrain cosmological parameters of the $\Lambda$CDM model and the astrophysical parameters related to hydrogen reionization. The…

Cosmology and Nongalactic Astrophysics · Physics 2021-08-18 Atrideb Chatterjee , Tirthankar Roy Choudhury , Sourav Mitra

When fitting cosmological models to data, a Bayesian framework is commonly used, requiring assumptions on the form of the likelihood and model prior. In light of current tensions between different data, it is interesting to investigate the…

Cosmology and Nongalactic Astrophysics · Physics 2024-10-31 Jordan Krywonos , Simone Paradiso , Alex Krolewski , Shahab Joudaki , Will Percival

We perform cosmological parameters estimation on Planck Cosmic Microwave Background (CMB) maps masking the recently discovered foreground related to nearby spiral galaxies. In addition, we also analyse the association between these…

Cosmology and Nongalactic Astrophysics · Physics 2025-03-19 Facundo Toscano , Frode K. Hansen , Diego Garcia Lambas , Heliana Luparello , Pablo Fosalba , Enrique Gaztañaga

In cosmic shear likelihood analyses the covariance is most commonly assumed to be constant in parameter space. Therefore, when calculating the covariance matrix (analytically or from simulations), its underlying cosmology should not…

Astrophysics · Physics 2015-05-13 Tim Eifler , Peter Schneider , Jan Hartlap

Research on the cosmic microwave background (CMB) is progressing rapidly. New experimental groups are popping up and two new satellites will be launched. The current enthusiasm to measure fluctuations in the CMB power spectrum at angular…

Astrophysics · Physics 2007-05-23 C. H. Lineweaver

We derive constraints on cosmological parameters using the power spectrum of galaxy clustering measured from the final two-degree field galaxy redshift survey (2dFGRS) and a compilation of measurements of the temperature power spectrum and…

We compare and combine likelihood functions of the cosmological parameters Omega_m, h and sigma_8, from peculiar velocities, CMB and type Ia supernovae. These three data sets directly probe the mass in the Universe, without the need to…

Astrophysics · Physics 2009-10-31 S. L. Bridle , I. Zehavi , A. Dekel , O. Lahav , M. P. Hobson , A. N. Lasenby

We introduce a new method to propagate uncertainties in the beam shapes used to measure the cosmic microwave background to cosmological parameters determined from those measurements. The method, which we call Markov Chain Beam…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 G. Rocha , L. Pagano , K. M. Górski , K. M. Huffenberger , C. R. Lawrence , A. E. Lange

Anomalies in the cosmic microwave background (CMB) refer to features that have been observed, mostly at large angular scales, and which show some tension with the statistical predictions of the standard $\Lambda$CDM model. In this work, we…

General Relativity and Quantum Cosmology · Physics 2021-05-28 Ivan Agullo , Dimitrios Kranas , V. Sreenath

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

The discussion of cosmological parameters used to be a source of embarrassment to cosmologists. Today, measurements of the cosmological parameters are leading the way into the era of precision cosmology. The CMB temperature is measured to…

Astrophysics · Physics 2009-10-31 Michael S. Turner

The likelihood function is a crucial element of parameter estimation. In analyses of galaxy overdensities and weak lensing shear, one often approximates the likelihood of the power spectrum with a Gaussian distribution. The posterior…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 L. Sun , Q. Wang , H. Zhan

We revisit the problem of exact CMB likelihood and power spectrum estimation with the goal of minimizing computational cost through linear compression. This idea was originally proposed for CMB purposes by Tegmark et al.\ (1997), and here…

Instrumentation and Methods for Astrophysics · Physics 2015-11-18 E. Gjerløw , L. P. L. Colombo , H. K. Eriksen , K. M. Górski , A. Gruppuso , J. B. Jewell , S. Plaszczynski , I. K. Wehus

We describe an approximate statistical model for the sample variance distribution of the non-linear matter power spectrum that can be calibrated from limited numbers of simulations. Our model retains the common assumption of a multivariate…

‹ Prev 1 3 4 5 6 7 10 Next ›