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Using the first station of the Long Wavelength Array (LWA1), we examine polarized pulsar emission between 25 and 88 MHz. Polarized light from pulsars undergoes Faraday rotation as it passes through the magnetized interstellar medium.…

High Energy Astrophysical Phenomena · Physics 2020-07-01 V. Dike , G. B. Taylor , J. Dowell , K. Stovall

Centaurus (Cen) A represents one of the best candidates for an isolated, compact, highly polarized source that is bright at typical cosmic microwave background (CMB) experiment frequencies. We present measurements of the 4 degree by 2…

We present an updated version of POLARIS, a well established code designated for dust polarisation and line radiative transfer (RT) in arbitrary astrophysical environments. We extend the already available capabilities with a synchrotron…

Astrophysics of Galaxies · Physics 2019-11-06 Stefan Reissl , Robert Brauer , Ralf S. Klessen , Eric W. Pellegrini

Spin-echo instruments are typically used to measure diffusive processes and the dynamics and motion in samples on ps and ns timescales. A key aspect of the spin-echo technique is to determine the polarisation of a particle beam. We present…

Materials Science · Physics 2018-02-05 Anton Tamtögl , Benjamin Davey , David J. Ward , Andrew P. Jardine , John Ellis , William Allison

(abridged) We run a Faraday structure determination data challenge to benchmark the currently available algorithms including Faraday synthesis (previously called RM synthesis in the literature), wavelet, compressive sampling and…

A detailed and formal account of polarization measurements using Bayesian analysis is given based on the assumption of gaussian error for the Stokes parameters. This analysis is crucial for the measurement of the polarization degree and…

Instrumentation and Methods for Astrophysics · Physics 2015-06-04 Jason L. Quinn

We consider continuous-time sparse stochastic processes from which we have only a finite number of noisy/noiseless samples. Our goal is to estimate the noiseless samples (denoising) and the signal in-between (interpolation problem). By…

Machine Learning · Computer Science 2015-06-11 Arash Amini , Ulugbek S. Kamilov , Emrah Bostan , Michael Unser

Estimating the number of signals embedded in noise is a fundamental problem in array signal processing. The classic RMT estimator based on random matrix theory (RMT) tends to under-estimate the number of signals as it does not consider the…

Information Theory · Computer Science 2020-10-28 Huiyue Yi

We present the first spectropolarimetric radio observations that apply Rotation Measure (RM) Synthesis to interferometric data from the Giant Metrewave Radio Telescope (GMRT) at 610 MHz. Spectropolarimetry requires measurement of a large…

Instrumentation and Methods for Astrophysics · Physics 2013-09-19 J. S. Farnes , D. A. Green , N. G. Kantharia

Polarization induced by cosmological scalar perturbations leads to a typical anisotropy pattern, which can best be analyzed in Fourier domain. This allows one to unambiguously distinguish cosmological signal of polarization from other…

Astrophysics · Physics 2009-10-28 Uros Seljak

Phase retrieval (PR) is a popular research topic in signal processing and machine learning. However, its performance degrades significantly when the measurements are corrupted by noise or outliers. To address this limitation, we propose a…

Optimization and Control · Mathematics 2025-05-30 Jun Fan , Ailing Yan , Xianchao Xiu , Wanquan Liu

In this work, we investigate the regularized solutions and their finite element solutions to the inverse source problems governed by partial differential equations, and establish the stochastic convergence and optimal finite element…

Numerical Analysis · Mathematics 2021-10-25 Zhiming Chen , Wenlong Zhang , Jun Zou

We present the results of an Australia Telescope Compact Array 1.4 GHz spectropolarimetric aperture synthesis survey of 34 square degrees centred on Centaurus A - NGC 5128. A catalogue of 1005 extragalactic compact radio sources in the…

We extend the rotation measure work of Burn (1966) to the cases of limited sampling of lambda squared space and non-constant emission spectra. We introduce the rotation measure transfer function (RMTF), which is an excellent predictor of…

Astrophysics · Physics 2009-11-13 M. A. Brentjens , A. G. de Bruyn

We report on the continuum and polarization observations of the Cygnus Loop supernova remnant (SNR) conducted by the Five-hundred-meter Aperture Spherical radio Telescope (FAST). FAST observations provide high angular resolution and high…

Astrophysics of Galaxies · Physics 2021-08-24 Xiaohui Sun , Meiniang Meng , Xuyang Gao , Wolfgang Reich , Peng Jiang , Di Li , Huirong Yan , Xianghua Li

We report on full-polarization radio observations of the Perseus cluster (Abell 426) using the Westerbork Synthesis Radio Telescope (WSRT) at wavelengths from 81-95 cm. We have employed a novel technique, Rotation Measure synthesis…

Astrophysics · Physics 2009-11-13 A. G. de Bruyn , M. A. Brentjens

We present a study of unbiased reconstruction of cosmic microwave background (CMB) polarization maps from data collected by modern ground-based observatories. Atmospheric emission is a major source of correlated noise in such experiments,…

Instrumentation and Methods for Astrophysics · Physics 2025-12-08 Simon Biquard , Josquin Errard , Radek Stompor

Rotation measure synthesis allows the estimation of Faraday dispersion via a Fourier transform and is the primary tool to probe cosmic magnetic fields. We show this can be considered mathematically equivalent to the one dimensional…

Instrumentation and Methods for Astrophysics · Physics 2020-05-13 Luke Pratley , Melanie Johnston-Hollitt

We present results of interferometric polarization observations of the recently discovered magnetar J1745-2900 in the vicinity of the Galactic center. The observations were made with the Karl G. Jansky Very Large Array (VLA) on 21 February…

Astrophysics of Galaxies · Physics 2016-05-13 E. V. Kravchenko , W. D. Cotton , F. Yusef-Zadeh , Y. Y. Kovalev

Direction-dependent instrumental polarisation introduces wide-field polarimetric aberrations and limits the dynamic range of low-frequency interferometric images. We therefore provide a detailed two-dimensional analysis of the Giant…

Instrumentation and Methods for Astrophysics · Physics 2014-07-03 J. S. Farnes