English
Related papers

Related papers: Fast Spherical Harmonic Analysis: a quick algorith…

200 papers

Current and planned observations of the cosmic microwave background (CMB) polarization anisotropies, with their ever increasing number of detectors, have reached a potential accuracy that requires a very demanding control of systematic…

Cosmology and Nongalactic Astrophysics · Physics 2017-02-01 Eric Hivon , Sylvain Mottet , Nicolas Ponthieu

We propose a new internal linear combination (ILC) method in the pixel space, applicable on large angular scales of the sky, to estimate a foreground minimized Cosmic Microwave Background (CMB) temperature anisotropy map by incorporating…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-07 Vipin Sudevan , Rajib Saha

A new algorithm for the stable solution of a three-dimensional scalar inverse problem of acoustic sounding of an inhomogeneous medium in a cylindrical region is proposed. The data of the problem is the complex amplitude of the wave field,…

Numerical Analysis · Mathematics 2022-03-30 Anatoly B. Bakushinsky , Alexander S. Leonov

Cosmic strings are linear topological defects that may have been produced during symmetry-breaking phase transitions in the very early Universe. In an expanding Universe the existence of causally separate regions prevents such symmetries…

Cosmology and Nongalactic Astrophysics · Physics 2024-03-15 Matthew A. Price , Matthijs Mars , Matthew M. Docherty , Alessio Spurio Mancini , Augustin Marignier , Jason. D. McEwen

We consider a cosmological model with non-Gaussian initial perturbations, which in principle could be generated in non-standard inflationary scenarios with two or more scalar fields. In particular we focus our attention on the model…

Astrophysics · Physics 2011-05-10 Dmitri Novikov , Jens Schmalzing , Viatcheslav F. Mukhanov

Wide-field imaging has become a major challenge for modern radio astronomy, which uses high sensitivity acquisition systems that deal with huge amounts of data. In this paper we investigate a fast wide-field imaging solution based on the…

Instrumentation and Methods for Astrophysics · Physics 2019-04-19 Luis F. R. Lucas , Chris J. Skipper , Anna M. M. Scaife

Within the context of upcoming full-sky lensing surveys, the edge-preserving non- linear algorithm Aski is presented. Using the framework of Maximum A Posteriori inversion, it aims at recovering the full-sky convergence map from surveys…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-13 C. Pichon , E. Thiebaut , S. Prunet , K. Benabed , S. Colombi , T. Sousbie , R. Teyssier

We use quadratic maximum-likelihood (QML) estimators to constrain models with Gaussian but statistically anisotropic Cosmic Microwave Background (CMB) fluctuations, using CMB maps with realistic sky-coverage and instrumental noise. This…

Cosmology and Nongalactic Astrophysics · Physics 2012-03-06 Duncan Hanson , Antony Lewis

The arrival time distribution of cosmic ray events is well suited to extract information regarding sky anisotropies. For an experiment with nearly constant exposure, the frequency resolution one can achieve is given by the inverse of the…

Astrophysics · Physics 2009-06-23 Pierre Billoir , Antoine Letessier-Selvon

This work is concerned with the following fundamental question in scientific machine learning: Can deep-learning-based methods solve noise-free inverse problems to near-perfect accuracy? Positive evidence is provided for the first time,…

Image and Video Processing · Electrical Eng. & Systems 2022-07-13 Martin Genzel , Ingo Gühring , Jan Macdonald , Maximilian März

We constrain several models of the early Universe that predict a statistical anisotropy of the cosmic microwave background (CMB) sky. We make use of WMAP9 maps deconvolved with beam asymmetries. As compared to previous releases of WMAP…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-03 Sabir Ramazanov , Grigory Rubtsov

In the field of optics and nanophotonics, simulation of electromagnetic scattering plays a major role in the study of complex nanostructures and optical devices. The numerical analysis of scattering spectra, even for nanocavities with…

The lensing of CMB photons by intervening large-scale structure leaves a characteristic imprint on its arcminute-scale anisotropy that can be used to map the dark matter distribution in projection on degree scales or ~100 Mpc/h comoving. We…

Astrophysics · Physics 2009-11-06 Wayne Hu

Deep cosmic microwave background polarization experiments allow a very precise internal reconstruction of the gravitational lensing signal in pricinple. For this aim, likelihood-based or Bayesian methods are typically necessary, where very…

Cosmology and Nongalactic Astrophysics · Physics 2023-10-25 Martin Reinecke , Sebastian Belkner , Julien Carron

We have performed a 70 billion dark-matter particles N-body simulation in a 2 $h^{-1}$ Gpc periodic box, using the concordance, cosmological model as favored by the latest WMAP3 results. We have computed a full-sky convergence map with a…

The Wavelength-Oriented Microwave Background Analysis Team (WOMBAT) is constructing microwave maps which will be more realistic than previous simulations. Our foreground models represent a considerable improvement: where spatial templates…

Gravitational lensing of the microwave background by the intervening dark matter mainly arises from large-angle fluctuations in the projected gravitational potential and hence offers a unique opportunity to study the physics of the dark…

Astrophysics · Physics 2011-05-12 Takemi Okamoto , Wayne Hu

We study accuracy, robustness and self-consistency of pixel-domain simulations of the gravitational lensing effect on the primordial CMB anisotropies due to the large-scale structure of the Universe. In particular, we investigate dependence…

Cosmology and Nongalactic Astrophysics · Physics 2013-08-09 Giulio Fabbian , Radek Stompor

We describe a system that builds a high dynamic-range and wide-angle image of the night sky by combining a large set of input images. The method makes use of pixel-rank information in the individual input images to improve a "consensus"…

Computer Vision and Pattern Recognition · Computer Science 2014-06-09 Dustin Lang , David W. Hogg , Bernhard Scholkopf

Multi-frequency observations are needed to separate the CMB from foregrounds and accurately extract cosmological information from the data. The Analytical Blind Separation (ABS) method is dedicated to extracting the CMB power spectrum from…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-22 Larissa Santos , Jian Yao , Le Zhang , Shamik Ghosh , Pengjie Zhang , Wen Zhao , Thyrso Villela , Jiming Chen , Jacques Delabrouille