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Context: Radio interferometers measure frequency components of the sky brightness, modulated by the gains of the individual radio antennas. Due to atmospheric turbulence and variations in the operational conditions of the antennas these…

Instrumentation and Methods for Astrophysics · Physics 2023-10-25 Jakob Roth , Philipp Arras , Martin Reinecke , Richard A. Perley , Rüdiger Westermann , Torsten A. Enßlin

Radio interferometric imaging aims to estimate an unknown sky intensity image from degraded observations, acquired through an antenna array. In the theoretical case of a perfectly calibrated array, it has been shown that solving the…

Instrumentation and Methods for Astrophysics · Physics 2017-07-25 Audrey Repetti , Jasleen Birdi , Arwa Dabbech , Yves Wiaux

The paper reviews progress in imaging in radio interferometry for the period 1993-1996. Unlike an optical telescope, the basic measurements of a radio interferometer (correlations between antennas) are indirectly related to a sky brightness…

Astrophysics · Physics 2007-05-23 R. J. Sault , T. A. Oosterloo

We present a new approach to multi-frequency synthesis in radio astronomy. Using Bayesian inference techniques, the new technique estimates the sky brightness and the spectral index simultaneously. In principle, the bandwidth of a wide-band…

Instrumentation and Methods for Astrophysics · Physics 2015-09-16 H. Junklewitz , M. A. Bell , T. Enßlin

Distributed calibration based on consensus optimization is a computationally efficient method to calibrate large radio interferometers such as LOFAR and SKA. Calibrating along multiple directions in the sky and removing the bright…

Instrumentation and Methods for Astrophysics · Physics 2021-10-29 Sarod Yatawatta

Radio Interferometry is an essential method for astronomical observations. Self-calibration techniques have increased the quality of the radio astronomical observations (and hence the science) by orders of magnitude. Recently, there is a…

Astrophysics · Physics 2008-11-03 Sarod Yatawatta , Saleem Zaroubi , Ger de Bruyn , Leon Koopmans , Jan Noordam

High fidelity radio interferometric data calibration that minimises spurious spectral structure in the calibrated data is essential in astrophysical applications, such as 21 cm cosmology, which rely on knowledge of the relative spectral…

Instrumentation and Methods for Astrophysics · Physics 2022-10-26 Peter H. Sims , Jonathan C. Pober , Jonathan L. Sievers

In radio astronomy, accurate calibration is of crucial importance for the new generation of radio interferometers. More specifically, because of the potential presence of outliers which affect the measured data, robustness needs to be…

Instrumentation and Methods for Astrophysics · Physics 2018-08-01 Virginie Ollier , Mohammed Nabil El Korso , André Ferrari , Rémy Boyer , Pascal Larzabal

Radio interferometric gain calibration can be biased by incomplete sky models and radio frequency interference, resulting in calibration artefacts that can restrict the dynamic range of the resulting images. It has been suggested that…

Instrumentation and Methods for Astrophysics · Physics 2019-10-21 Ulrich Armel Mbou Sob , Hertzog Landman Bester , Oleg Smirnov , Jonathan Kenyon , Trienko Grobler

This paper investigates calibration of sensor arrays in the radio astronomy context. Current and future radio telescopes require computationally efficient algorithms to overcome the new technical challenges as large collecting area, wide…

Applications · Statistics 2018-07-31 Virginie Ollier , Mohammed Nabil El Korso , André Ferrari , Rémy Boyer , Pascal Larzabal

Line-intensity mapping (LIM) is an emerging cosmological technique that traces large-scale structure through the integrated spectral-line emission of unresolved sources. Reconstructing unbiased sky maps requires careful joint treatment of…

Instrumentation and Methods for Astrophysics · Physics 2026-03-25 Zheng Zhang , Philip Bull , Mario G. Santos , Ainulnabilah Nasirudin

This paper summarizes some of the major calibration and image reconstruction techniques used in radio interferometry and describes them in a common mathematical framework. The use of this framework has a number of benefits, ranging from…

Instrumentation and Methods for Astrophysics · Physics 2009-11-26 U. Rau , S. Bhatnagar , M. A. Voronkov , T. J. Cornwell

Uncertainty quantification is a critical missing component in radio interferometric imaging that will only become increasingly important as the big-data era of radio interferometry emerges. Statistical sampling approaches to perform…

Instrumentation and Methods for Astrophysics · Physics 2018-09-12 Xiaohao Cai , Marcelo Pereyra , Jason D. McEwen

Interferometric calibration always yields non unique solutions. It is therefore essential to remove these ambiguities before the solutions could be used in any further modeling of the sky, the instrument or propagation effects such as the…

Instrumentation and Methods for Astrophysics · Physics 2013-07-19 Sarod Yatawatta

Calibration is an essential step in radio interferometric data processing that corrects the data for systematic errors and in addition, subtracts bright foreground interference to reveal weak signals hidden in the residual. These weak and…

Instrumentation and Methods for Astrophysics · Physics 2019-05-08 Sarod Yatawatta

Calibration is a key step in the signal processing pipeline of any radio astronomical instrument. The required sky, ionospheric and instrumental models for this step can suffer from various kinds of incompleteness. In this paper we analyze…

Instrumentation and Methods for Astrophysics · Physics 2019-02-08 A. Mouri Sardarabadi , L. V. E. Koopmans

We present a novel, general-purpose method for deconvolving and denoising images from gridded radio interferometric visibilities using Bayesian inference based on a Gaussian process model. The method automatically takes into account…

Instrumentation and Methods for Astrophysics · Physics 2015-06-17 P. M. Sutter , Benjamin D. Wandelt , Jason D. McEwen , Emory F. Bunn , Ata Karakci , Andrei Korotkov , Peter Timbie , Gregory S. Tucker , Le Zhang

Uncertainty quantification is a critical missing component in radio interferometric imaging that will only become increasingly important as the big-data era of radio interferometry emerges. Since radio interferometric imaging requires…

Instrumentation and Methods for Astrophysics · Physics 2018-09-12 Xiaohao Cai , Marcelo Pereyra , Jason D. McEwen

In order to meet the theoretically achievable imaging performance, calibration of modern radio interferometers is a mandatory challenge, especially at low frequencies. In this perspective, we propose a novel parallel iterative…

Instrumentation and Methods for Astrophysics · Physics 2016-09-09 Martin Brossard , Mohammed Nabil El Korso , Marius Pesavento , Rémy Boyer , Pascal Larzabal , Stefan J. Wijnholds

We propose a novel framework for joint magnetic resonance image reconstruction and uncertainty quantification using under-sampled k-space measurements. The problem is formulated as a Bayesian linear inverse problem, where prior…

Image and Video Processing · Electrical Eng. & Systems 2026-03-17 Ahmed Karam Eldaly , Matteo Figini , Daniel C. Alexander
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