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We study a practical algorithm for sparse principal component analysis (PCA) of incomplete and noisy data. Our algorithm is based on the semidefinite program (SDP) relaxation of the non-convex $l_1$-regularized PCA problem. We provide…

Machine Learning · Statistics 2022-09-16 Hanbyul Lee , Qifan Song , Jean Honorio

Primordial B-mode detection is one of the main goals of current and future cosmic microwave background (CMB) experiments. However, the weak B-mode signal is overshadowed by several Galactic polarized emissions, such as thermal dust emission…

Cosmology and Nongalactic Astrophysics · Physics 2023-04-18 Ye-Peng Yan , Guo-Jian Wang , Si-Yu Li , Jun-Qing Xia

The polarization of the Cosmic Microwave Background (CMB)is a powerful observational tool at hand for modern cosmology. It allows to break the degeneracy of fundamental cosmological parameters one cannot obtain using only anisotropy data…

Astrophysics · Physics 2009-11-07 M. V. Sazhin , G. Sironi , O. S. Khovanskaya

While emission and absorption lines of the 21 cm spin-flip transition of neutral Hydrogen are intrinsically unpolarized, a magnetic field creates left- and right-handed polarized components through the Zeeman effect. Here we consider the…

Astrophysics · Physics 2016-08-30 Asantha Cooray , Steven Furlanetto

One of the main problems for extracting the Cosmic Microwave Background (CMB) from submm/mm observations is to correct for the Galactic components, mainly synchrotron, free - free and thermal dust emission with the required accuracy.…

Cosmology and Nongalactic Astrophysics · Physics 2018-10-17 H. U. Nørgaard-Nielsen

We present a brief review of the main results of the Planck 2015 release describing the new calibration of the data, showing the maps delivered in temperature and, for the first time, in polarization, the cosmological parameters and the…

Cosmology and Nongalactic Astrophysics · Physics 2016-05-06 Nazzareno Mandolesi , Diego Molinari , Alessandro Gruppuso , Carlo Burigana , Paolo Natoli

Correlations between cosmic microwave background (CMB) temperature, polarization and spectral distortion anisotropies can be used as a probe of primordial non-Gaussianity. Here, we perform a reconstruction of $\mu$-distortion anisotropies…

Cosmology and Nongalactic Astrophysics · Physics 2018-05-02 M. Remazeilles , J. Chluba

We study how 21 cm intensity mapping can be used to measure gravitational lensing over a wide range of redshift. This can extend weak lensing measurements to higher redshifts than are accessible with conventional galaxy surveys. We…

Cosmology and Nongalactic Astrophysics · Physics 2014-03-11 A. Pourtsidou , R. Benton Metcalf

The Multi-frequency Angular Power Spectrum (MAPS) is an alternative to spherically-averaged power spectra, and computes local fluctuations in the angular power spectrum without need for line-of-sight spectral transform. To test different…

Cosmology and Nongalactic Astrophysics · Physics 2022-10-19 Cathryn M. Trott , Rajesh Mondal , Garrelt Mellema , Steven G. Murray , Bradley Greig , Jack L. B. Line , Nichole Barry , Miguel F. Morales

Polarization is the next frontier of CMB analysis, but its signal is dominated over much of the sky by foregrounds which must be carefully removed. To determine the efficacy of this cleaning it is necessary to have sensitive tests for…

Astrophysics · Physics 2007-09-06 Duncan Hanson , Douglas Scott , Emory F. Bunn

Recent results of the ESA Planck satellite have confirmed the existence of some anomalies in the statistical distribution of the cosmic microwave background (CMB) anisotropies. One of the most intriguing anomalies is the Cold Spot, firstly…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-16 R. Fernández-Cobos , P. Vielva , E. Martínez-González , M. Tucci , M. Cruz

The polarized Galactic thermal dust emission constitutes a major probe for the study and the characterization of the Galactic Magnetic Field (GMF). In this paper, we apply the maximum-likelihood analysis that we established in our companion…

Astrophysics of Galaxies · Physics 2021-11-03 Vincent Pelgrims , Juan Francisco Macías-Pérez

We forecast ability of dedicated 21 cm intensity mapping experiments to constraint primordial non-Gaussianity using power spectrum and bispectrum. We model the signal including the non-linear biasing expansion using a generalized halo model…

Cosmology and Nongalactic Astrophysics · Physics 2020-11-30 Dionysios Karagiannis , Anže Slosar , Michele Liguori

We present in this paper a new Bayesian semi-blind approach for foreground removal in observations of the 21-cm signal with interferometers. The technique, which we call HIEMICA (HI Expectation-Maximization Independent Component Analysis),…

Cosmology and Nongalactic Astrophysics · Physics 2016-01-20 Le Zhang , Emory F. Bunn , Ata Karakci , Andrei Korotkov , P. M. Sutter , Peter T. Timbie , Gregory S. Tucker , Benjamin D. Wandelt

We apply the Correlated Component Analysis (CCA) method on simulated data of the Square Kilometre Array, with the aim of accurately cleaning the 21 cm reionization signal from diffuse foreground contamination. The CCA has been developed for…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-22 Anna Bonaldi , Michael L. Brown

In this report, a novel efficient algorithm for recovery of jointly sparse signals (sparse matrix) from multiple incomplete measurements has been presented, in particular, the NESTA-based MMV optimization method. In a nutshell, the jointly…

Information Theory · Computer Science 2009-05-21 Lianlin Li , Fang Li

We have analyzed the available polarization surveys of the Galactic emission to estimate to what extent it may be a serious hindrance to forthcoming experiments aimed at detecting the polarized component of Cosmic Microwave Background (CMB)…

Astrophysics · Physics 2009-10-31 C. Baccigalupi , C. Burigana , F. Perrotta , G. De Zotti , L. La Porta , D. Maino , M. Maris , R. Paladini

Absorption or emission against the cosmic microwave background radiation (CMB) may be observed in the redshifted 21cm line if the spin temperature of the neutral intergalactic medium prior to reionization differs from the CMB temperature.…

Astrophysics · Physics 2009-12-10 Tiziana Di Matteo , Rosalba Perna , Tom Abel , Martin J. Rees

We present a method to delens the acoustic peaks of the CMB temperature and polarization power spectra internally, using lensing maps reconstructed from the CMB itself. We find that when delensing CMB acoustic peaks with a lensing potential…

Cosmology and Nongalactic Astrophysics · Physics 2017-05-31 Neelima Sehgal , Mathew S. Madhavacheril , Blake Sherwin , Alexander van Engelen

Unsupervised learning makes manifest the underlying structure of data without curated training and specific problem definitions. However, the inference of relationships between data points is frustrated by the `curse of dimensionality' in…