Resolving 4-D Nature of Magnetism with Depolarization and Faraday Tomography: Japanese SKA Cosmic Magnetism Science

Akahori, Takuya; Fujita, Yutaka; Ichiki, Kiyotomo; Ideguchi, Shinsuke; Kudoh, Takahiro; Kudoh, Yuki; Machida, Mami; Nakanishi, Hiroyuki; Ohno, Hiroshi; Ozawa, Takeaki; Takahashi, Keitaro; Takizawa, Motokazu

doi:10.48550/arxiv.1603.01974

Cited by 2 publications

(2 citation statements)

References 109 publications

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“…For the purpose of prototyping, SKA-like science pipelines could be developed to cover the technical requirements for any of these areas. We have here chosen to focus on the science case of magnetic fields, which can be advantageous from a prototyping perspective as the data processing requires full-Stokes polarization imaging in I, Q, U, and V [2], together with Faraday Tomography [3][4][5][6], which intrinsically has substantial computing requirements. The Big Data challenges associated with Faraday Tomography will be further increased at SKA sensitivities, for which a 'forest' of signatures is expected to be generated along each line of sight [7].…”

Section: Magnetism Surveys As Prototyping Test-bedsmentioning

confidence: 99%

Science Pipelines for the Square Kilometre Array

Farnes¹,

Mort²,

Dulwich³

et al. 2018

Preprint

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The Square Kilometre Array (SKA) will be both the largest radio telescope ever constructed and the largest Big Data project in the known Universe. The first phase of the project will generate on the order of 5 zettabytes of data per year. A critical task for the SKA will be its ability to process data for science, which will need to be conducted by science pipelines. Together with polarization data from the LOFAR Multifrequency Snapshot Sky Survey (MSSS), we have been developing a realistic SKA-like science pipeline that can handle the large data volumes generated by LOFAR at 150 MHz. The pipeline uses task-based parallelism to image, detect sources, and perform Faraday Tomography across the entire LOFAR sky. The project thereby provides a unique opportunity to contribute to the technological development of the SKA telescope, while simultaneously enabling cutting-edge scientific results. In this paper, we provide an update on current efforts to develop a science pipeline that can enable tight constraints on the magnetised large-scale structure of the Universe.

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Section: Magnetism Surveys As Prototyping Test-bedsmentioning

confidence: 99%

Science Pipelines for the Square Kilometre Array

Farnes¹,

Mort²,

Dulwich³

et al. 2018

Preprint

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“…Understanding cosmic magnetism from the scale of interstellar gas to galaxy clusters is crucial in understanding their astrophysical processes (e.g., Gaensler et al 2004;Beck 2009;Johnston-Hollitt et al 2015;Akahori et al 2016Akahori et al , 2018. One of the main techniques to obtain the magnetic information of these objects is through observations of polarized radio emission.…”

Section: Introductionmentioning

confidence: 99%

Wavelets and sparsity for Faraday tomography

Cooray,

Takeuchi,

Ideguchi

et al. 2021

Preprint

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Faraday tomography through broadband polarimetry can provide crucial information on magnetized astronomical objects, such as quasars, galaxies, or galaxy clusters. However, the limited wavelength coverage of the instruments requires that we solve an ill-posed inverse problem when we want to obtain the Faraday dispersion function (FDF), a tomographic distribution of the magnetoionic media along the line of sight. This paper explores the use of wavelet transforms and the sparsity of the transformed FDFs in the form of wavelet shrinkage (WS) for finding better solutions to the inverse problem. We recently proposed the Constraining and Restoring iterative Algorithm for Faraday Tomography (CRAFT; Cooray et al. 2021), a new flexible algorithm that showed significant improvements over the popular methods such as Rotation Measure Synthesis. In this work, we introduce CRAFT+WS, a new version of CRAFT incorporating the ideas of wavelets and sparsity. CRAFT+WS exhibit significant improvements over the original CRAFT when tested for a complex FDF of realistic Galactic model. Reconstructions of FDFs demonstrate super-resolution in Faraday depth, uncovering previously unseen Faraday complexities in observations. The proposed approach will be necessary for effective cosmic magnetism studies using the Square Kilometre Array and its precursors. The code is made publicly available ‡ .

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Resolving 4-D Nature of Magnetism with Depolarization and Faraday Tomography: Japanese SKA Cosmic Magnetism Science

Cited by 2 publications

References 109 publications

Science Pipelines for the Square Kilometre Array

Science Pipelines for the Square Kilometre Array

Wavelets and sparsity for Faraday tomography

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