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Large patterns could exist on the microwave sky as a result of various non-standard possibilities for the large-scale Universe -- rotation or shear, non-trivial topology, and single topological defects are specific examples. All-sky (or…

Astrophysics · Physics 2009-10-31 Emory F. Bunn , Douglas Scott

The presence of astrophysical emissions between the last scattering surface and our vantage point requires us to apply a foreground mask on CMB sky map, leading to large cut around the Galactic equator and numerous holes. Since many CMB…

Cosmology and Nongalactic Astrophysics · Physics 2012-04-17 Jaiseung Kim , Pavel Naselsky , Nazzareno Mandolesi

The detection of B-mode polarization in the CMB is one of the most important outstanding tests of inflationary cosmology. One of the necessary steps for extracting polarization information in the CMB is reducing contamination from so-called…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-17 Jude Bowyer , Andrew H. Jaffe , Dmitri I. Novikov

This paper studies random fields on the unit sphere. Traditionally, isotropic Gaussian random fields are considered as the underlying statistical model of the cosmic microwave background (CMB) data. This paper discusses the generalized…

General Physics · Physics 2021-04-30 Phil Broadbridge , Ravindi Nanayakkara , Andriy Olenko

We discuss the problem of CMB spectrum corruption during Galactic emission removing. A new technique of spatial--frequency data reduction is proposed. The technique gives us a possibility to avoid a spatial harmonics nonorthogonality. The…

Astrophysics · Physics 2007-05-23 A. A. Brukhanov , D. P. Skulachev , I. A. Strukov , T. V. Konkina

Upcoming microwave background experiments will see an incredible increase in the volume of data to be analyzed, which makes the choice of how it is discretized on the sky a crucial issue. I discuss criteria for evaluating different…

Astrophysics · Physics 2007-05-23 Robert G. Crittenden

Deep surveys of the CMB polarization have more information on the lensing signal than the quadratic estimators (QE) can capture. We showed in a recent work that a CMB lensing power spectrum built from a single optimized CMB lensing mass…

Cosmology and Nongalactic Astrophysics · Physics 2023-11-15 Louis Legrand , Julien Carron

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

Phases of the spherical harmonic analysis of full-sky cosmic microwave background (CMB) temperature data contain useful information complementary to the ubiquitous angular power spectrum. In this letter we present a new method of phase…

Astrophysics · Physics 2009-11-16 Lung-Yih Chiang , Pavel D. Naselsky

The spherical harmonic transform is a powerful tool in the analysis of spherical data sets, such as the cosmic microwave background data. In this work, we present a new scheme for the spherical harmonic transforms that supports both CPU and…

Instrumentation and Methods for Astrophysics · Physics 2022-11-18 Chi Tian , Siyu Li , Hao Liu

We present a comprehensive study of the regularity of the covariance matrix of a discretized field on the sphere. In a particular situation, the rank of the matrix depends on the number of pixels, the number of spherical harmonics, the…

Cosmology and Nongalactic Astrophysics · Physics 2017-04-12 J. D. Bilbao-Ahedo , R. B. Barreiro , D. Herranz , P. Vielva , E. Martínez-González

We present a method to measure the small-scale matter power spectrum using high-resolution measurements of the gravitational lensing of the Cosmic Microwave Background (CMB). To determine whether small-scale structure today is suppressed on…

Cosmology and Nongalactic Astrophysics · Physics 2019-01-16 Ho Nam Nguyen , Neelima Sehgal , Mathew Madhavacheril

We describe a novel method for the application of Convolutional Neural Networks (CNNs) to fields defined on the sphere, using the HEALPix tessellation scheme. Specifically, We have developed a pixel-based approach to implement convolutional…

Instrumentation and Methods for Astrophysics · Physics 2019-08-21 Nicoletta Krachmalnicoff , Maurizio Tomasi

The role of cosmic microwave background (CMB) polarisation data in constraining the presence of primordial isocurvature modes is examined. While the MAP satellite mission will be unable to simultaneously constrain isocurvature modes and…

Astrophysics · Physics 2009-10-31 M Bucher , K Moodley , N Turok

A fundamental assumption in cosmology is that of statistical isotropy - that the universe, on average, looks the same in every direction in the sky. Statistical isotropy has recently been tested stringently using Cosmic Microwave Background…

Cosmology and Nongalactic Astrophysics · Physics 2011-09-14 Caroline Zunckel , Dragan Huterer , Glenn D. Starkman

We report an improved technique for diffuse foreground minimization from Cosmic Microwave Background (CMB) maps using a new multi-phase iterative internal-linear-combination (ILC) approach in harmonic space. The new procedure consists of…

Cosmology and Nongalactic Astrophysics · Physics 2017-09-18 Vipin Sudevan , Pavan K. Aluri , Sarvesh Kumar Yadav , Rajib Saha , Tarun Souradeep

The COBE satellite has provided the only comprehensive multi-frequency full-sky observations of the microwave sky available today. Assessment of the observations requires a detailed likelihood analysis to extract the maximum amount of…

Astrophysics · Physics 2007-05-23 K. M. Gorski

Wavelets on the sphere are reintroduced and further developed independently of the original group theoretic formalism, in an equivalent, but more straightforward approach. These developments are motivated by the interest of the scale-space…

Astrophysics · Physics 2008-11-26 Y. Wiaux , L. Jacques , P. Vandergheynst

We present a new method for fast computation of the realization-dependent bias, a major computational bottleneck in measurements of the cosmic microwave background (CMB) lensing power spectrum. The method accelerates the bias calculation by…

Cosmology and Nongalactic Astrophysics · Physics 2026-05-19 Toshiya Namikawa , Blake D. Sherwin

A great deal of experimental effort is currently being devoted to the precise measurements of the cosmic microwave background (CMB) sky in temperature and polarisation. Satellites, balloon-borne, and ground-based experiments scrutinize the…