Cosmic magnetism in centimeter- and meter-wavelength radio astronomy

Akahori, Takuya; Nakanishi, Hiroyuki; Sofue, Yoshiaki; Fujita, Yutaka; Ichiki, Kiyotomo; Ideguchi, Shinsuke; Kameya, Osamu; Kudoh, Takahiro; Kudoh, Yuki; Machida, Mami; Miyashita, Yoshimitsu; Ohno, Hiroshi; Ozawa, T.; Takahashi, Keitaro; Takizawa, Motokazu; Yamazaki, Dai

doi:10.1093/pasj/psx123

Cited by 45 publications

(29 citation statements)

References 491 publications

(521 reference statements)

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“…Large scale mappings of Faraday rotation measure (RM) of extragalactic linearly polarized radio sources have been achieved extensively in the decades (Taylor et al 2009;Oppermann et al 2012), with which various analyses have been obtained to investigate structures of galactic as well as intergalactic magnetic fields (e.g., review by Akahori et al 2018).…”

Section: Introductionmentioning

confidence: 99%

Magnetic field and ISM in the local Galactic disc

Sofue

Nakanishi

Ichiki

2019

Monthly Notices of the Royal Astronomical Society

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Correlation analysis is obtained among Faraday rotation measure, HI column density, thermal and synchrotron radio brightness using archival all-sky maps of the Galaxy. A method is presented to calculate the magnetic strength and its line-of-sight (LOS) component, volume gas densities, effective LOS depth, effective scale height of the disk from these data in a hybrid way. Applying the method to archival data, all-sky maps of the local magnetic field strength and its parallel component are obtained, which reveal details of local field orientation.

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Section: Introductionmentioning

confidence: 99%

Magnetic field and ISM in the local Galactic disc

Sofue

Nakanishi

Ichiki

2019

Monthly Notices of the Royal Astronomical Society

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“…Quite on the contrary, several may contribute either simultaneously or sequentially, sympatrically or allopatrically, to the magnetization of the IGM 1 . Disentangling their respective contributions may become possible in the near future thanks to synchrotron measurements and Faraday tomography (e.g., [77,78])-especially when compared to numerical simulations that are able to track the various contributions [79,80]-or even in the statistical properties of the neutral gas during the epoch of reionization [81,82]. 1 Among the possible contributions is the resistive mechanism suggested in [76], in which temperature inhomogeneities of the IGM are responsible for spatial variations of the resistivity that induce rotational electric fields thanks to cosmic ray driven return currents.…”

Section: Discussionmentioning

confidence: 99%

Magnetizing the Cosmic Web during Reionization

Langer

Durrive

2018

Galaxies

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Increasing evidence suggests that cosmological sheets, filaments, and voids may be substantially magnetized today. The origin of magnetic fields in the intergalactic medium (IGM) is, however, currently uncertain. It seems well known that non-standard extensions to the physics of the standard model can provide mechanisms susceptible of magnetizing the universe at large. Perhaps less well known is the fact that standard, classical physics of matter-radiation interactions actually possesses the same potential. We discuss a magnetogenesis mechanism based on the exchange of momentum between hard photons and electrons in an inhomogeneous IGM. Operating in the neighborhood of ionizing sources during the epoch of reionization, this mechanism is capable of generating magnetic seeds of relevant strengths over scales comparable to the distance between ionizing sources. In addition, summing up the contributions of all ionizing sources and taking into account the distribution of gas inhomogeneities, we show that this mechanism leaves the IGM, at the end of reionization, with a level of magnetization that might account, when amplification mechanisms take over, for the magnetic fields strengths in the current cosmic web.

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Section: Introductionmentioning

confidence: 99%

“…The morphology of magnetic fields in galaxies can be classified based on its dominant mode: Axis-Symmetric Spiral (ASS, m = 0), Bi-Symmetric Spiral (BSS, m = 1), and Quadri-Symmetric Spiral (QSS, m = 2) types [2]. The azimuthal changes of RM can be used to classify the morphology and to solve the 180 • -ambiguity [2]. Former works have shown that IC342 and M31, for example, are classified into ASS [3,4] and that M81, M33 and NGC 6946 are classified into BSS [5,6] by examining azimuthal changes of RM.…”

Section: Introductionmentioning

confidence: 99%

Magnetic-Field Vector Maps of Nearby Spiral Galaxies

2019

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We present a method for determining directions of magnetic field vectors in a spiral galaxy using two synchrotron polarization maps, an optical image, and a velocity field. The orientation of the transverse magnetic field is determined with a synchrotron polarization map of higher frequency band and the 180 • -ambiguity is solved by using sign of the Rotation Measure (RM) after determining geometrical orientation of a disk based on a assumption of trailing spiral arms. The advantage of this method is that direction of magnetic vector for each line of sight through the galaxy can be inexpensively determined with easily available data and with simple assumptions. We applied this method to three nearby spiral galaxies using archival data obtained with the Very Large Array (VLA) to demonstrate how it works. The three galaxies have both clockwise and counter-clockwise magnetic fields, which implies that all three galaxies are not classified in simple Axis-Symmetric type but types of higher modes and that magnetic reversals commonly exist.

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Cosmic magnetism in centimeter- and meter-wavelength radio astronomy

Cited by 45 publications

References 491 publications

Magnetic field and ISM in the local Galactic disc

Magnetic field and ISM in the local Galactic disc

Magnetizing the Cosmic Web during Reionization

Magnetic-Field Vector Maps of Nearby Spiral Galaxies

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