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Related papers: Imaging VLBI polarimetry data from Active Galactic…

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We investigate statistical and individual astrophysical properties of active galactic nuclei (AGNs), such as parsec-scale flux density, core dominance, angular and linear sizes, maximum observed brightness temperatures of VLBI core…

Cosmology and Nongalactic Astrophysics · Physics 2015-03-20 A. B. Pushkarev , Y. Y. Kovalev

We have performed a 70 billion dark-matter particles N-body simulation in a 2 $h^{-1}$ Gpc periodic box, using the concordance, cosmological model as favored by the latest WMAP3 results. We have computed a full-sky convergence map with a…

We report on multi-frequency polarimetry Very Long Baseline Interferometry observations of active galactic nuclei using the VLBA. These observations are used to construct images of the Faraday Rotation Measure (RM) in J1613+342, Mrk 501, 3C…

Cosmology and Nongalactic Astrophysics · Physics 2015-05-20 G. B. Taylor , R. Zavala

In radio-interferometry, we recover an image from an incompletely sampled Fourier data. The de-facto standard algorithm, the Cotton-Schwab CLEAN, is iteratively switching between computing a deconvolution (minor loop) and subtracting the…

Instrumentation and Methods for Astrophysics · Physics 2026-02-04 Hendrik Müller , Mingyu Hsieh , Sanjay Bhatnagar

Using diffusion models to solve inverse problems is a growing field of research. Current methods assume the degradation to be known and provide impressive results in terms of restoration quality and diversity. In this work, we leverage the…

Computer Vision and Pattern Recognition · Computer Science 2025-06-02 Charles Laroche , Andrés Almansa , Eva Coupete

Masked Diffusion Models (MDMs) offer flexible, non-autoregressive generation, but this freedom introduces a challenge: final output quality is highly sensitive to the decoding order. We are the first to formalize this issue, attributing the…

Computation and Language · Computer Science 2025-12-25 Ziyu Chen , Xinbei Jiang , Peng Sun , Tao Lin

When the predicted sequence length exceeds the length seen during training, the transformer's inference accuracy diminishes. Existing relative position encoding methods, such as those based on the ALiBi technique, address the length…

Machine Learning · Computer Science 2024-03-27 Weiguo Gao

We have studied Very Long Baseline Array (VLBA) polarimetric observations of 8 sources including quasars and BL Lacs at 12, 15, 22, 24 and 43 GHz and high frequency rotation measure ($RM$) maps are presented. We find typical values for the…

High Energy Astrophysical Phenomena · Physics 2015-06-12 J. C. Algaba

Modern deep neural networks achieved remarkable progress in medical image segmentation tasks. However, it has recently been observed that they tend to produce overconfident estimates, even in situations of high uncertainty, leading to…

Computer Vision and Pattern Recognition · Computer Science 2023-06-05 Agostina Larrazabal , Cesar Martinez , Jose Dolz , Enzo Ferrante

Representation learning is currently a very hot topic in modern machine learning, mostly due to the great success of the deep learning methods. In particular low-dimensional representation which discriminates classes can not only enhance…

Machine Learning · Computer Science 2015-04-13 Wojciech Marian Czarnecki , Rafał Józefowicz , Jacek Tabor

We perform polarimetry analysis of 20 active galactic nuclei (AGN) jets using the Very Long Baseline Array (VLBA) at 1.4, 1.6, 2.2, 2.4, 4.6, 5.0, 8.1, 8.4, and 15.4 GHz. The study allowed us to investigate linearly polarized properties of…

High Energy Astrophysical Phenomena · Physics 2018-03-12 E. V. Kravchenko , Y. Y. Kovalev , K. V. Sokolovsky

Single-particle imaging with X-ray free-electron lasers depends crucially on algorithms that merge large numbers of weak diffraction patterns despite missing measurements of parameters such as particle orientations. The…

Computational Physics · Physics 2021-08-24 B. R. Mobley , K. E. Schmidt , J. P. Chen , R. A. Kirian

The new technique, multi-frequency imaging (MFI) is developed. In VLBI, Multi-Frequency Imaging (MFI) consists of multi-frequency synthesis (MFS) and multi-frequency analysis (MFA) of the VLBI data obtained from observations on various…

Astrophysics · Physics 2007-05-23 S. Likhachev

The calibration and analysis of polarization observations in Very Long Baseline Interferometry (VLBI) requires the use of specific algorithms that suffer from several limitations, closely related to assumptions in the data properties that…

Instrumentation and Methods for Astrophysics · Physics 2021-02-10 Ivan Marti-Vidal , Alejandro Mus , Michael Janssen , Pablo de Vicente , Javier Gonzalez

In this paper we study the computation of the nonparametric maximum likelihood estimator (NPMLE) in multivariate mixture models. Our first approach discretizes this infinite dimensional convex optimization problem by fixing the support…

Methodology · Statistics 2024-02-20 Yangjing Zhang , Ying Cui , Bodhisattva Sen , Kim-Chuan Toh

M87 is one of the nearest radio galaxies with a central SMBH and a prominent relativistic jet. Due to its close distance to the observer and the large SMBH mass, the source is one of the best laboratories to obtain strong observational…

Astrophysics of Galaxies · Physics 2016-09-27 J. -Y. Kim , R. -S. Lu , T. P. Krichbaum , M. Bremer , J. A. Zensus , R. C. Walker , the M87 collaboration

This paper revisits the fundamental equations for the solution of the frictionless unilateral normal contact problem between a rough rigid surface and a linear elastic half-plane using the boundary element method (BEM). After recasting the…

Materials Science · Physics 2015-06-02 A. Bemporad , M. Paggi

Data sizes for next generation radio telescopes, such as the Square Kilometre Array (SKA), are far above that of their predecessors. The CLEAN algorithm was originally developed by H\"ogbom [1974], long before such data sizes were thought…

Instrumentation and Methods for Astrophysics · Physics 2025-01-06 Daniel Wright , Karel Adámek , Wesley Armour

Lensing of the CMB is now a well-developed probe of large-scale clustering over a broad range of redshifts. By exploiting the non-Gaussian imprints of lensing in the polarization of the CMB, the CORE mission can produce a clean map of the…

Cosmology and Nongalactic Astrophysics · Physics 2019-08-13 Anthony Challinor , Rupert Allison , Julien Carron , Josquin Errard , Stephen Feeney , Thomas Kitching , Julien Lesgourgues , Antony Lewis , Íñigo Zubeldía , Ana Achucarro , Peter Ade , Mark Ashdown , Mario Ballardini , A. J. Banday , Ranajoy Banerji , James Bartlett , Nicola Bartolo , Soumen Basak , Daniel Baumann , Marco Bersanelli , Anna Bonaldi , Matteo Bonato , Julian Borrill , François Bouchet , François Boulanger , Thejs Brinckmann , Martin Bucher , Carlo Burigana , Alessandro Buzzelli , Zhen-Yi Cai , Martino Calvo , Carla-Sofia Carvalho , Gabriella Castellano , Jens Chluba , Sebastien Clesse , Ivan Colantoni , Alessandro Coppolecchia , Martin Crook , Giuseppe d'Alessandro , Paolo de Bernardis , Giancarlo de Gasperis , Gianfranco De Zotti , Jacques Delabrouille , Eleonora Di Valentino , Jose-Maria Diego , Raul Fernandez-Cobos , Simone Ferraro , Fabio Finelli , Francesco Forastieri , Silvia Galli , Ricardo Genova-Santos , Martina Gerbino , Joaquin González-Nuevo , Sebastian Grandis , Joshua Greenslade , Steffen Hagstotz , Shaul Hanany , Will Handley , Carlos Hernandez-Monteagudo , Carlos Hervías-Caimapo , Matthew Hills , Eric Hivon , Kimmo Kiiveri , Ted Kisner , Martin Kunz , Hannu Kurki-Suonio , Luca Lamagna , Anthony Lasenby , Massimiliano Lattanzi , Michele Liguori , Valtteri Lindholm , Marcos López-Caniego , Gemma Luzzi , Bruno Maffei , Enrique Martinez-González , C. J. A. P. Martins , Silvia Masi , Darragh McCarthy , Alessandro Melchiorri , Jean-Baptiste Melin , Diego Molinari , Alessandro Monfardini , Paolo Natoli , Mattia Negrello , Alessio Notari , Alessandro Paiella , Daniela Paoletti , Guillaume Patanchon , Michel Piat , Giampaolo Pisano , Linda Polastri , Gianluca Polenta , Agnieszka Pollo , Vivian Poulin , Miguel Quartin , Mathieu Remazeilles , Matthieu Roman , Jose-Alberto Rubino-Martin , Laura Salvati , Andrea Tartari , Maurizio Tomasi , Denis Tramonte , Neil Trappe , Tiziana Trombetti , Carole Tucker , Jussi Valiviita , Rien Van de Weijgaert , Bartjan van Tent , Vincent Vennin , Patricio Vielva , Nicola Vittorio , Karl Young , Mario Zannoni

In the current paradigm, it is believed that the compact VLBI radio core of radio-loud AGNs represents the innermost upstream regions of relativistic outflows. These regions of AGN jets have generally been modeled by a conical outflow with…

High Energy Astrophysical Phenomena · Physics 2017-01-11 Juan-Carlos Algaba , Masanori Nakamura , Keiichi Asada , Sang-Sung Lee
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