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The line-of-sight structure of the Galactic magnetic field (GMF) can be studied using Faraday rotation measure (RM) grids. We analyze how the choice of interpolation kernel can affect the accuracy and reliability of reconstructed RM maps.…

Instrumentation and Methods for Astrophysics · Physics 2024-12-24 Affan Khadir , Ayush Pandhi , Sebastian Hutschenreuter , Bryan Gaensler , Shannon Vanderwoude , Jennifer West , Shane O'Sullivan

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 determined Faraday rotation measures (RMs) towards 137 pulsars in the northern sky, using Low-Frequency Array (LOFAR) observations at 110-190 MHz. This low-frequency RM catalogue, the largest to date, improves the precision of existing…

(abridged) Observations of Faraday rotation for extragalactic sources probe magnetic fields both inside and outside the Milky Way. Building on our earlier estimate of the Galactic contribution, we set out to estimate the extragalactic…

A direct consequence of Faraday rotation is that the polarized radio sky does not resemble the total intensity sky at long wavelengths. We analyze G137+7, which is undetectable in total intensity but appears as a depolarization feature. We…

In this work we present a novel compute framework for reconstructing Faraday depth signals from noisy and incomplete spectro-polarimetric radio datasets. This framework is based on a compressed-sensing approach that addresses a number of…

Instrumentation and Methods for Astrophysics · Physics 2022-06-08 Miguel Cárcamo , Anna Scaife , Russ Taylor , Matt Jarvis , Micah Bowles , Srikrishna Sekhar , Lennart Heino , Jeroen Stil

We consider the problem of localizing relevant subsets of non-rigid geometric shapes given only a partial 3D query as the input. Such problems arise in several challenging tasks in 3D vision and graphics, including partial shape similarity,…

Computational Geometry · Computer Science 2019-06-17 Arianna Rampini , Irene Tallini , Maks Ovsjanikov , Alex M. Bronstein , Emanuele Rodolà

The aim of this paper is to describe a novel non-parametric noise reduction technique from the point of view of Bayesian inference that may automatically improve the signal-to-noise ratio of one- and two-dimensional data, such as e.g.…

Instrumentation and Methods for Astrophysics · Physics 2023-07-07 Pablo M Sanchez-Alarcon , Yago Ascasibar Sequeiros

The use of Quantum Neural Networks (QNN) that are analogous to classical neural networks, has greatly increased in the past decade owing to the growing interest in the field of Quantum Machine Learning (QML). A QNN consists of three major…

Quantum Physics · Physics 2024-01-30 Koustubh Phalak , Swaroop Ghosh

We develop a new approach for studying flux anomalies in quadruply-imaged fold lens systems. We show that in the absence of substructure, microlensing, or differential absorption, the expected flux ratios of a fold pair can be tightly…

Cosmology and Nongalactic Astrophysics · Physics 2014-11-20 David M. Goldberg , Mary K. Chessey , Wendy B. Harris , Gordon T. Richards

We present a diagnostic test of possible Galactic contamination of cosmic microwave background sky maps designed to provide an independent check on the methods used to compile these maps. The method involves a non-parametric measurement of…

Astrophysics · Physics 2009-11-10 Patrick Dineen , Peter Coles

We aim to summarize the current state of knowledge regarding Galactic Faraday rotation in an all-sky map of the Galactic Faraday depth. For this we have assembled the most extensive catalog of Faraday rotation data of compact extragalactic…

Faraday rotation of polarised background sources is a unique probe of astrophysical magnetic fields in a diverse range of foreground objects. However, to understand the properties of the polarised sources themselves and of depolarising…

Using commissioning data from the first year of operation of the Canadian Hydrogen Intensity Mapping Experiment's (CHIME) Pulsar backend system, we conduct a systematic analysis of the Faraday Rotation Measure (RM) of the northern…

Instrumentation and Methods for Astrophysics · Physics 2020-06-17 C. Ng , A. Pandhi , A. Naidu , E. Fonseca , V. M. Kaspi , K. W. Masui , R. Mckinven , A. Renard , P. Scholz , I. H. Stairs , S. P. Tendulkar , K. Vanderlinde

We consider gravity mediated by non-metricity, with vanishing curvature and torsion. The gravitational action, including an arbitrary function of the non-metric scalar, is investigated in view of characterizing the dark energy effects. In…

General Relativity and Quantum Cosmology · Physics 2022-07-13 Salvatore Capozziello , Rocco D'Agostino

To obtain the initial pressure from the collected data on a planar sensor arrangement in Photoacoustic tomography, there exists an exact analytic frequency domain reconstruction formula. An efficient realization of this formula needs to…

Numerical Analysis · Mathematics 2015-01-14 Julian Schmid , Thomas Glatz , Behrooz Zabihian , Mengyang Liu , Wolfgang Drexler , Otmar Scherzer

The Polarisation Sky Survey of the Universe's Magnetism (POSSUM) will conduct a sensitive $\sim$1 GHz radio polarization survey covering 20 000 square degrees of the Southern sky with the Australian Square Kilometre Array Pathfinder…

For the first time it has become possible to compare global 3D general relativistic magnetohydrodynamic (GRMHD) jet formation simulations directly to very-long baseline interferometric multi-frequency polarization observations of the…

High Energy Astrophysical Phenomena · Physics 2015-05-19 Avery E. Broderick , Jonathan C. McKinney

Polarization calibration of interferometric observations is a costly procedure and, in some cases (e.g., a limited coverage of parallactic angle for the calibrator), it may not be possible to be performed. To avoid this worst-case scenario…

Instrumentation and Methods for Astrophysics · Physics 2023-04-05 E. Albentosa-Ruiz , I. Marti-Vidal

The ability to control the speed and polarisation of light pulses will allow for faster data flow in optical networks of the future. Optical delay and switching have been achieved using slow-light techniques in various media, including…

Atomic Physics · Physics 2009-04-08 Paul Siddons , Nia C Bell , Yifei Cai , Charles S Adams , Ifan G Hughes