Performance test of RM CLEAN and its evaluation with chi-square value

Miyashita, Yoshimitsu; Ideguchi, Shinsuke; Takahashi, Keitaro

doi:10.1093/pasj/psw039

Cited by 16 publications

(16 citation statements)

References 36 publications

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“…In addition, when F(f) is constructed from an observed polarization spectrum, effects such as a false signal in RM CLEAN (Farnsworth et al 2011;Kumazaki et al 2014;Miyashita et al 2016) as well as the limited frequency coverage and noises in observation need to be considered. For instance, the shape of F(f) could depend on the wavelength because of an imperfect Fourier transform due to the limited sampling of the squared wavelength.…”

Section: Summary and Discussionmentioning

confidence: 99%

Study of the Vertical Magnetic Field in Face-on Galaxies Using Faraday Tomography

Ideguchi

Tashiro

Akahori

et al. 2017

ApJ

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Faraday tomography allows astronomers to probe the distribution of the magnetic field along the line of sight (LOS), but that can be achieved only after the Faraday spectrum is interpreted. However, the interpretation is not straightforward, mainly because the Faraday spectrum is complicated due to a turbulent magnetic field; it ruins the one-to-one relation between the Faraday depth and the physical depth, and appears as many small-scale features in the Faraday spectrum. In this paper, by employing "simple toy models" for the magnetic field, we describe numerically as well as analytically the characteristic properties of the Faraday spectrum. We show that the Faraday spectrum along "multiple LOSs" can be used to extract the global properties of the magnetic field. Specifically, considering face-on spiral galaxies and modeling turbulent magnetic field as a random field with a single coherence length, we numerically calculate the Faraday spectrum along a number of LOSs and its shape-characterizing parameters, that is, the moments. When multiple LOSs cover a region of (10 coherence length) 2 , the shape of the Faraday spectrum becomes smooth and the shape-characterizing parameters are well specified. With the Faraday spectrum constructed as a sum of Gaussian functions with different means and variances, we analytically show that the parameters are expressed in terms of the regular and turbulent components of the LOS magnetic field and the coherence length. We also consider the turbulent magnetic field modeled with a power-law spectrum, and study how the magnetic field is revealed in the Faraday spectrum. Our work suggests a way to obtain information on the magnetic field from a Faraday tomography study.

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Section: Summary and Discussionmentioning

confidence: 99%

Study of the Vertical Magnetic Field in Face-on Galaxies Using Faraday Tomography

Ideguchi

Tashiro

Akahori

et al. 2017

ApJ

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“…Some techniques have been proposed to overcome such problems and to optimize the reconstruction of Faraday-complex spectra (Frick et al 2010;Li et al 2011). All of them assume a model for the synchrotronemitting and Faraday rotating medium, and nowadays their performances are still tested and debated (see, e.g., Sun et al 2015;Miyashita et al 2016;Schnitzeler 2018;Ideguchi et al 2018, for the comparison of RM clean with other methods).…”

Section: Faraday-complex Emissionmentioning

confidence: 99%

Particle re-acceleration and Faraday-complex structures in the RXC J1314.4-2515 galaxy cluster

Stuardi

Bonafede

Wittor

et al. 2019

Monthly Notices of the Royal Astronomical Society

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Radio relics are sites of electron (re)acceleration in merging galaxy clusters but the mechanism of acceleration and the topology of the magnetic field in and near relics are yet to be understood. We are carrying out an observational campaign on double relic galaxy clusters starting with RXC J1314.4-2515. With Jansky Very Large Array multi-configuration observations in the frequency range 1-4 GHz, we perform both spectral and polarization analyses, using the Rotation Measure synthesis technique. We use archival XMM-Newton observations to constrain the properties of the shocked region. We discover a possible connection between the activity of a radio galaxy and the emission of the eastern radio relic. In the northern elongated arc of the western radio relic, we detect polarized emission with an average polarization fraction of 31 % at 3 GHz and we derive the Mach number of the underlying X-ray shock. Our observations reveal low levels of fractional polarization and Faraday-complex structures in the southern region of the relic, which point to the presence of thermal gas and filamentary magnetic field morphology inside the radio emitting volume. We measured largely different Rotation Measure dispersion from the two relics. Finally, we use cosmological magneto-hydrodynamical simulations to constrain the magnetic field, viewing angle, and to derive the acceleration efficiency of the shock. We find that the polarization properties of RXC J1314.4-2515 are consistent with a radio relic observed at 70 • with respect to the line of sight and that efficient re-acceleration of fossil electrons has taken place.

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“…The following works do not address the technical problems of Faraday tomography. Improvement of Faraday tomography such as RM CLEAN and QU-fitting [60][61][62][63][64] is another important work; see also some articles in this volume.…”

Section: The Power Of Faraday Tomographymentioning

confidence: 99%

Strategy to Explore Magnetized Cosmic Web with Forthcoming Large Surveys of Rotation Measure

Akahori

2018

Galaxies

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The warm-hot intergalactic medium (WHIM) is a candidate for the missing baryons in the Universe. If the WHIM is permeated with the intergalactic magnetic field (IGMF), the Faraday rotation measure (RM) of the WHIM is imprinted in linearly-polarized emission from extragalactic objects. In this article, we discuss strategies to explore the WHIM’s RM from forthcoming radio broadband and wide-field polarization sky surveys. There will be two observational breakthroughs in the coming decades; the RM grid and Faraday tomography. They will allow us to find ideal RM sources for the study of the IGMF and give us unique information of the WHIM along the line of sight.

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Performance test of RM CLEAN and its evaluation with chi-square value

Cited by 16 publications

References 36 publications

Study of the Vertical Magnetic Field in Face-on Galaxies Using Faraday Tomography

Study of the Vertical Magnetic Field in Face-on Galaxies Using Faraday Tomography

Particle re-acceleration and Faraday-complex structures in the RXC J1314.4-2515 galaxy cluster

Strategy to Explore Magnetized Cosmic Web with Forthcoming Large Surveys of Rotation Measure

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