Cygnus A super-resolved via convex optimisation from VLA data

Arwa Dabbech, Alexandru Onose, Abdullah Abdulaziz, Richard A. Perley, Oleg M. Smirnov, Yves Wiaux

Research output: Contribution to journalArticle

Abstract

We leverage the Sparsity Averaging Reweighted Analysis (SARA) approach for interferometric imaging, that is based on convex optimisation, for the super-resolution of Cyg A from observations at the frequencies 8.422GHz and 6.678GHz with the Karl G. Jansky Very Large Array (VLA). The associated average sparsity and positivity priors enable image reconstruction beyond instrumental resolution. An adaptive Preconditioned Primal-Dual algorithmic structure is developed for imaging in the presence of unknown noise levels and calibration errors. We demonstrate the superior performance of the algorithm with respect to the conventional clean-based methods, reflected in super-resolved images with high fidelity. The high resolution features of the recovered images are validated by referring to maps of Cyg A at higher frequencies, more precisely 17.324GHz and 14.252GHz. We also confirm the recent discovery of a radio transient in the Cyg A galaxy, revealed in the reconstructed images of the two investigated data sets.
LanguageEnglish
Pages2853–2866
Number of pages14
JournalMonthly Notices of the Royal Astronomical Society
Volume476
Issue number3
Early online date13 Feb 2018
DOIs
Publication statusPublished - 21 May 2018

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Very Large Array (VLA)
optimization
image reconstruction
galaxies
high resolution

Keywords

  • Techniques: image processing
  • Techniques: interferometric
  • galaxies: CygA

Cite this

Dabbech, Arwa ; Onose, Alexandru ; Abdulaziz, Abdullah ; Perley, Richard A. ; Smirnov, Oleg M. ; Wiaux, Yves. / Cygnus A super-resolved via convex optimisation from VLA data. In: Monthly Notices of the Royal Astronomical Society. 2018 ; Vol. 476, No. 3. pp. 2853–2866.
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Cygnus A super-resolved via convex optimisation from VLA data. / Dabbech, Arwa; Onose, Alexandru; Abdulaziz, Abdullah; Perley, Richard A.; Smirnov, Oleg M.; Wiaux, Yves.

In: Monthly Notices of the Royal Astronomical Society, Vol. 476, No. 3, 21.05.2018, p. 2853–2866.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Cygnus A super-resolved via convex optimisation from VLA data

AU - Dabbech, Arwa

AU - Onose, Alexandru

AU - Abdulaziz, Abdullah

AU - Perley, Richard A.

AU - Smirnov, Oleg M.

AU - Wiaux, Yves

PY - 2018/5/21

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AB - We leverage the Sparsity Averaging Reweighted Analysis (SARA) approach for interferometric imaging, that is based on convex optimisation, for the super-resolution of Cyg A from observations at the frequencies 8.422GHz and 6.678GHz with the Karl G. Jansky Very Large Array (VLA). The associated average sparsity and positivity priors enable image reconstruction beyond instrumental resolution. An adaptive Preconditioned Primal-Dual algorithmic structure is developed for imaging in the presence of unknown noise levels and calibration errors. We demonstrate the superior performance of the algorithm with respect to the conventional clean-based methods, reflected in super-resolved images with high fidelity. The high resolution features of the recovered images are validated by referring to maps of Cyg A at higher frequencies, more precisely 17.324GHz and 14.252GHz. We also confirm the recent discovery of a radio transient in the Cyg A galaxy, revealed in the reconstructed images of the two investigated data sets.

KW - Techniques: image processing

KW - Techniques: interferometric

KW - galaxies: CygA

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