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The advent of large aperture arrays, such as the currently under construction Square Kilometer Array (SKA), allows for observing the universe in the radio-spectrum at unprecedented resolution and sensitivity. However, these telescopes…

Instrumentation and Methods for Astrophysics · Physics 2024-12-04 S. Wang , S. Prunet , S. Mignot , A. Ferrari

The multiple Doppler readouts available on the Laser Interferometer Space Antenna (LISA) permit simultaneous formation of several interferometric observables. All these observables are independent of laser frequency fluctuations and have…

General Relativity and Quantum Cosmology · Physics 2009-11-07 Thomas A. Prince , Massimo Tinto , Shane L. Larson , J. W. Armstrong

Radio interferometers consisting of identical antennas arranged on a regular lattice permit fast Fourier transform beamforming, which reduces the correlation cost from $\mathcal{O}(n^2)$ in the number of antennas to $\mathcal{O}(n\log n)$.…

Instrumentation and Methods for Astrophysics · Physics 2019-05-20 Kiyoshi W. Masui , J. Richard Shaw , Cherry Ng , Kendrick M. Smith , Keith Vanderlinde , Adiv Paradise

Many scientific deliverables of the next generation low frequency radio telescopes require high dynamic range imaging. Next generation telescopes under construction indeed promise at least a ten-fold increase in the sensitivity compared…

Instrumentation and Methods for Astrophysics · Physics 2009-06-03 S. Bhatnagar

Radio astronomical observation below 30 MHz is hampered by the refraction and absorption of the ionosphere, and the radio frequency interference (RFI), so far high angular resolution sky intensity map is not available. An interferometer…

Instrumentation and Methods for Astrophysics · Physics 2018-07-09 Qizhi Huang , Shijie Sun , Shifan Zuo , Fengquan Wu , Yidong Xu , Bin Yue , Reza Ansari , Xuelei Chen

Extraterrestrial communication signals are hypothesized to be present in an extensive search space. Using principles of communication theory and system design, methods are studied and implemented to reduce the signal search space, while…

Signal Processing · Electrical Eng. & Systems 2024-04-16 William J. Crilly

Hyperspectral imaging has become a significant source of valuable data for astronomers over the past decades. Current instrumental and observing time constraints allow direct acquisition of multispectral images, with high spatial but low…

Computer Vision and Pattern Recognition · Computer Science 2019-12-30 Claire Guilloteau , Thomas Oberlin , Olivier Berné , Nicolas Dobigeon

A key goal of radio and $\gamma-$ray observations of active galactic nuclei is to characterize their time variability in order to elucidate physical processes responsible for the radiation. I describe algorithms for relevant time series…

Instrumentation and Methods for Astrophysics · Physics 2010-06-25 Jeffrey D. Scargle

Metrewave solar type-III radio bursts offer a unique means to study the properties of turbulence across the coronal heights.Theoretical models have shown that the apparent intensity and size of the burst sources evolve at sub-second scales…

Solar and Stellar Astrophysics · Physics 2021-11-24 Atul Mohan

The daily measurements of the disc-integrated solar radio flux, observed by the Radio Solar Telescope Network (RSTN), at 245, 410, 610, 1415, 2695, 4995, and 8800 MHz during the time interval of 1989 January 1 to 2019 December 17, are used…

Solar and Stellar Astrophysics · Physics 2024-11-28 N. B. Xiang , X. H. Zhao , L. H. Deng , F. Y. Li , Y. J. Wang , X. W. Tan

Recent studies undoubtedly demonstrate that the magnetic field in the photosphere and corona is an intermittent structure, which offers new views on the underlying physics. In particular, such problems as the existence in the corona of…

Solar and Stellar Astrophysics · Physics 2011-02-11 Valentyna Abramenko , Vasyl Yurchyshyn , Haimin Wang

Electromagnetic wave scattering off density inhomogeneities in the solar corona is an important process which determines both the apparent source size and the time profile of radio bursts observed at 1 AU. Here we model the scattering…

Solar and Stellar Astrophysics · Physics 2019-03-05 N. H. Bian , A. G. Emslie , E. P. Kontar

Radio interferometry invariably suffers from an incomplete coverage of the spatial Fourier space, which leads to imaging artifacts. The current state-of-the-art technique is to create an image by Fourier-transforming the incomplete…

Instrumentation and Methods for Astrophysics · Physics 2024-12-19 F. Geyer , K. Schmidt , J. Kummer , M. Brüggen , H. W. Edler , D. Elsässer , F. Griese , A. Poggenpohl , L. Rustige , W. Rhode

This paper provides a general introduction to the problem of image reconstruction from interferometric data. A simple model of the interferometric observables is given and the issues arising from sparse Fourier data are discussed. The…

Instrumentation and Methods for Astrophysics · Physics 2017-08-29 Éric Thiébaut , John Young

Low frequency radio wave scattering and refraction can have a dramatic effect on the observed size and position of radio sources in the solar corona. The scattering and refraction is thought to be due to fluctuations in electron density…

Solar and Stellar Astrophysics · Physics 2021-01-04 Pearse C. Murphy , Eoin P. Carley , Aoife Maria Ryan , Pietro Zucca , Peter T. Gallagher

Radar interferometry usually exploits two complex-valued radar images with the same resolution to extract terrain elevation information. This paper considers the interferometry using two radar images with different resolutions, which we…

Information Theory · Computer Science 2018-12-14 Huizhang Yang , Chengzhi Chen , Shengyao Chen , Feng Xi , Zhong Liu

We propose a new algorithm, for parameter estimation that is applicable to imaging using moving and synthetic aperture arrays. The new method results in higher resolution and more accurate estimation than commonly used methods when strong…

Instrumentation and Methods for Astrophysics · Physics 2010-08-31 Ronny Levanda , Amir Leshem

To continue the unparalleled success of the Very Large Array (VLA) for radio astronomy, the facility is currently being converted to become the 'Expanded VLA' (EVLA). The EVLA will radically improve the VLA in order to cover the full…

Astrophysics · Physics 2009-11-13 Juergen Ott , Rick Perley , Michael Rupen , the EVLA team

Aims : We describe MS-MFS, a multi-scale multi-frequency deconvolution algorithm for wide-band synthesis-imaging, and present imaging results that illustrate the capabilities of the algorithm and the conditions under which it is feasible…

Instrumentation and Methods for Astrophysics · Physics 2015-05-28 Urvashi Rau , Tim J. Cornwell

We present a filtering technique that can be applied to individual baselines of wide-bandwidth, wide-field interferometric data to geometrically select regions on the celestial sphere that contain primary calibration sources. The technique…

Instrumentation and Methods for Astrophysics · Physics 2015-05-13 Aaron R. Parsons , Donald C. Backer