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Related papers: Performance test of QU-fitting in cosmic magnetism…

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QU-fitting is a powerful tool for interpreting spectro-polarimetric radio continuum observations by linking them to physical models, enabling estimates of the magnetic fields in, for example, the Milky Way, galaxy clusters, and radio jets.…

We present a new algorithm for fitting and classifying polarized radio sources, which is based on the QU fitting method introduced by O'Sullivan et al. and on our analysis of pulsars. Then we test this algorithm using Monte Carlo…

Instrumentation and Methods for Astrophysics · Physics 2020-06-17 D. H. F. M. Schnitzeler

RM CLEAN is a standard method to reconstruct the distribution of cosmic magnetic fields and polarized sources along the line of sight (LOS) from observed polarization spectrum. This method is similar to the CLEAN algorithm for aperture…

Astrophysics of Galaxies · Physics 2016-05-11 Yoshimitsu Miyashita , Shinsuke Ideguchi , Keitaro Takahashi

Markov Chain Monte Carlo (MCMC) techniques are now widely used for cosmological parameter estimation. Chains are generated to sample the posterior probability distribution obtained following the Bayesian approach. An important issue is how…

(Abridged) This paper introduces the formalism which connects between rotation measure ($\RM$) measurements for extragalactic sources and the cosmological magnetic field power spectrum. It is shown that the amplitude and shape of the…

Astrophysics · Physics 2016-08-30 Tsafrir Kolatt

Here, I overview one of the available techniques for the analysis of broad-band spectropolarimetric data, the Stokes QU-fitting. Since broad-band receivers have been installed at most radio facilities, the collection of radio data, both the…

Astrophysics of Galaxies · Physics 2021-08-24 Alice Pasetto

Recent attempts to constrain cosmological variation in the fine structure constant, alpha, using quasar absorption lines have yielded two statistical samples which initially appear to be inconsistent. One of these samples was subsequently…

Cosmology and Nongalactic Astrophysics · Physics 2009-10-16 Julian A. King , Daniel J. Mortlock , John K. Webb , Michael T. Murphy

We present a methodology to recover cosmic microwave background (CMB) polarization in which the quantity $P = Q+ iU$ is linearly combined at different frequencies using complex coefficients. This is the most general linear combination of…

Cosmology and Nongalactic Astrophysics · Physics 2016-04-06 R. Fernández-Cobos , A. Marcos-Caballero , P. Vielva , E. Martínez-González , R. B. Barreiro

We introduce a method to quantify the quality-of-fit between data and observables depending on the large scale Galactic magnetic field. We combine WMAP5 polarized synchrotron data and Rotation Measures of extragalactic sources in a joint…

Astrophysics of Galaxies · Physics 2009-07-22 Ronnie Jansson , Glennys R. Farrar , Andre H. Waelkens , Torsten A. Ensslin

Quasi-Monte Carlo (QMC) methods for estimating integrals are attractive since the resulting estimators typically converge at a faster rate than pseudo-random Monte Carlo. However, they can be difficult to set up on arbitrary posterior…

Statistics Theory · Mathematics 2018-10-03 Tobias Schwedes , Ben Calderhead

We consider the problem of improving the efficiency of randomized Fourier feature maps to accelerate training and testing speed of kernel methods on large datasets. These approximate feature maps arise as Monte Carlo approximations to…

Machine Learning · Statistics 2015-08-11 Haim Avron , Vikas Sindhwani , Jiyan Yang , Michael Mahoney

In statistical analysis, Monte Carlo (MC) stands as a classical numerical integration method. When encountering challenging sample problem, Markov chain Monte Carlo (MCMC) is a commonly employed method. However, the MCMC estimator is biased…

Numerical Analysis · Mathematics 2024-11-05 Jiarui Du , Zhijian He

We present broadband polarimetric observations of a sample of high Faraday rotation measure (RM) AGN using the VLA telescope from 1 to 2 GHz, and 4 to 12 GHz. The sample (14 sources) consists of compact sources (linear resolution smaller…

Multi-model fitting has been extensively studied from the random sampling and clustering perspectives. Most assume that only a single type/class of model is present and their generalizations to fitting multiple types of models/structures…

Computer Vision and Pattern Recognition · Computer Science 2019-01-30 Xun Xu , Loong-Fah Cheong , Zhuwen Li

The control of material loss mechanisms is playing an increasingly important role for improving coherence times of superconducting quantum devices. Such material losses can be characterized through the measurement of planar superconducting…

Geometric model fitting is a challenging but fundamental computer vision problem. Recently, quantum optimization has been shown to enhance robust fitting for the case of a single model, while leaving the question of multi-model fitting…

Computer Vision and Pattern Recognition · Computer Science 2023-03-28 Matteo Farina , Luca Magri , Willi Menapace , Elisa Ricci , Vladislav Golyanik , Federica Arrigoni

Recently PAMELA collaboration published the cosmic nuclei and electron spectra with high precision, together with the cosmic antiproton data updated, and the Fermi-LAT collaboration also updated the measurement of the total $e^+e^-$…

Cosmology and Nongalactic Astrophysics · Physics 2012-02-09 Jie Liu , Qiang Yuan , Xiao-Jun Bi , Hong Li , Xinmin Zhang

As integrated circuit (IC) geometry and packaging become more sophisticated with ongoing fabrication and design innovations, the electrical engineering community needs increasingly-powerful failure analysis (FA) methods to meet the growing…

Instrumentation and Detectors · Physics 2023-07-20 P. Kehayias , J. Walraven , A. L. Rodarte , A. M. Mounce

Bayesian inference in the physical sciences faces a fundamental challenge: the imperative for high-fidelity physical modeling often clashes with the intrinsic limitations of stochastic sampling algorithms. Complex, high-dimensional…

Instrumentation and Methods for Astrophysics · Physics 2026-04-09 Bo Liang , Chang Liu , Hanlin Song , Tianyu Zhao , Minghui Du , He Wang , Haohao Gu , Sensen He , Yuxiang Xu , Wei-Liang Qian , Li-e Qiang , Peng Xu , Ziren Luo , Mingming Sun

We investigate the capability of ongoing radio telescopes for probing Faraday rotation measure (RM) due to the intergalactic magnetic field (IGMF) in the large-scale structure of the universe which is expected to be of order $O(1) {\rm…

Cosmology and Nongalactic Astrophysics · Physics 2015-06-17 Shinsuke Ideguchi , Keitaro Takahashi , Takuya Akahori , Kohei Kumazaki , Dongsu Ryu
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