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The detection of the magnetic type $B$-mode polarization is the main goal of future cosmic microwave background (CMB) experiments. In the standard model, the $B$-mode map is a strongly non-gaussian field due to the lensed component. Besides…

Cosmology and Nongalactic Astrophysics · Physics 2016-07-20 Larissa Santos , Kai Wang , Wen Zhao

(abridged for arXiv) We report results from the BICEP2 experiment, a cosmic microwave background (CMB) polarimeter specifically designed to search for the signal of inflationary gravitational waves in the B-mode power spectrum around…

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

V-mode polarization of the cosmic microwave background is expected to be vanishingly small in the $\Lambda$CDM model and, hence, usually ignored. Nonetheless, several astrophysical effects, as well as beyond standard model physics could…

Cosmology and Nongalactic Astrophysics · Physics 2024-09-17 N. Raffuzzi , M. Lembo , S. Giardiello , M. Gerbino , M. Lattanzi , P. Natoli , L. Pagano

Next generation CMB experiments such as CMB-S4 aim at measuring the CMB lensing potential at sub-percent precision where most of the constraining power will come from CMB polarization. We investigate the prospects of achieving this goal in…

Cosmology and Nongalactic Astrophysics · Physics 2020-07-01 Dominic Beck , Josquin Errard , Radek Stompor

The search for primordial gravitational waves is a central goal of cosmic microwave background (CMB) surveys. Isolating the characteristic $B$-mode polarization signal sourced by primordial gravitational waves is challenging for several…

Cosmology and Nongalactic Astrophysics · Physics 2025-12-23 Eric Guzman , Joel Meyers

Curl lensing, also known as lensing field-rotation or shear B-modes, is a distinct post-Born observable caused by two lensing deflections at different redshifts (lens-lens coupling). For the Cosmic Microwave Background (CMB), the…

Cosmology and Nongalactic Astrophysics · Physics 2025-01-28 Mathew Robertson , Giulio Fabbian , Julien Carron , Antony Lewis

Recent studies report a mild discrepancy between baryon acoustic oscillation (BAO) and cosmic microwave background (CMB) measurements within the $\Lambda$CDM framework. This discrepancy could be explained if the optical depth $\tau$…

Cosmology and Nongalactic Astrophysics · Physics 2026-01-15 Yuta Kageura , Masami Ouchi , Fumihiro Naokawa , Hiroya Umeda , Akinori Matsumoto , Yuichi Harikane , Minami Nakane , Tran Thi Thai

We present a new approach to component separation in multifrequency CMB experiments by formulating the problem as that of partitioning the sky into pixel clusters such that within each pixel cluster the foregrounds have similar spectrum,…

Cosmology and Nongalactic Astrophysics · Physics 2019-03-18 Rishi Khatri

We present a novel method for Cosmic Microwave Background (CMB) foreground removal based on deep learning techniques. This method employs a Transformer model, referred to as \texttt{TCMB}, which is specifically designed to effectively…

Cosmology and Nongalactic Astrophysics · Physics 2025-10-09 Ye-Peng Yan , Si-Yu Li , Yang Liu , Jun-Qing Xia , Hong Li

Although interesting in themselves, extragalactic sources emitting in the microwave range (mainly radio-loud active galactic nuclei and dusty galaxies) are also considered a contaminant from the point of view of Cosmic Microwave Background…

Cosmology and Nongalactic Astrophysics · Physics 2021-03-31 P. Diego-Palazuelos , P. Vielva , D. Herranz

The quality of CMB observations has improved dramatically in the last few years, and will continue to do so in the coming decade. Over a wide range of angular scales, the uncertainty due to instrumental noise is now small compared to the…

Using a Gibbs sampling algorithm for joint CMB estimation and component separation, we compute the large-scale CMB and foreground posteriors of the 3-yr WMAP temperature data. Our parametric data model includes the cosmological CMB signal…

Astrophysics · Physics 2010-11-11 H. K. Eriksen , C. Dickinson , J. B. Jewell , A. J. Banday , K. M. Gorski , C. R. Lawrence

The most promising avenue for detecting primordial gravitational waves from cosmic inflation is through measurements of degree-scale CMB $B$-mode polarisation. This approach must face the challenge posed by gravitational lensing of the CMB,…

Cosmology and Nongalactic Astrophysics · Physics 2022-07-20 Antón Baleato Lizancos , Anthony Challinor , Blake D. Sherwin , Toshiya Namikawa

The detection of point-sources in microwave maps is a critical step in the analysis of the Cosmic Microwave Background (CMB) data. If not properly removed, these sources have adverse effects on the estimation of the power-spectrum and/or…

Astrophysics · Physics 2009-07-14 R. Vio , P. Andreani

Recently the second phase of Background Imaging of Cosmic Extragalactic Polarization (BICEP2) claimed a detection of the tensor-to-scalar ratio ($r$) of primordial fluctuation at $5\sigma$ confidence level. If it is true, this large and…

Cosmology and Nongalactic Astrophysics · Physics 2014-08-06 Yi Wang , Yin-Zhe Ma

As confusion with lensing B-modes begins to limit experiments that search for primordial B-mode polarization, robust methods for delensing the CMB polarization sky are becoming increasingly important. We investigate in detail the…

Cosmology and Nongalactic Astrophysics · Physics 2015-08-19 Blake D. Sherwin , Marcel Schmittfull

Cosmic microwave background (CMB) polarimetry has the potential to provide revolutionary advances in cosmology. Future experiments to detect the very weak B mode signal in CMB polarization maps will require unprecedented sensitivity and…

Astrophysics · Physics 2009-11-13 Peter Hyland , Brent Follin , Emory F. Bunn

The Quadratic Maximum Likelihood estimator can be used to reconstruct the Cosmic Microwave Background (CMB) power spectra with minimal error bars. Still, it requires an accurate estimate of the datasets noise covariance matrix in order to…

Cosmology and Nongalactic Astrophysics · Physics 2018-11-28 S. Vanneste , S. Henrot-Versillé , T. Louis , M. Tristram

We present an application of the fast Independent Component Analysis method to the COBE-DMR 4yr data. Although the signal-to-noise ratio in the COBE-DMR data is typically $\sim 1$, the approach is able to extract the CMB signal with high…

Astrophysics · Physics 2009-11-07 D. Maino , A. J. Banday , C. Baccigalupi , F. Perrotta , K. M. Gorski