A new perspective on turbulent Galactic magnetic fields through comparison of linear polarization decomposition techniques

J. -F. Robitaille, A. M. M. Scaife, E. Carretti, B. M. Gaensler, J. D. McEwen, B. Leistedt, M. Haverkorn, G. Bernardi, M. J. Kesteven, S. Poppi, L. Staveley-Smith

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Abstract

We compare two rotationally invariant decomposition techniques on linear polarization data: the spin-2 spherical harmonic decomposition in two opposite parities, the E- and B-mode, and the multiscale analysis of the gradient of linear polarization, vertical bar del P vertical bar. We demonstrate that both decompositions have similar properties in the image domain and the spatial frequency domain. They can be used as complementary tools for turbulence analysis of interstellar magnetic fields in order to develop a better understanding of the origin of energy sources for the turbulence, the origin of peculiar magnetic field structures and their underlying physics. We also introduce a new quantity vertical bar del EB vertical bar based on the E-and B-modes and we show that in the intermediate-and small-scale limit vertical bar del EB vertical bar similar or equal to vertical bar del P vertical bar. Analysis of the 2.3 GHz S-band Polarization All Sky Survey shows many extended coherent filament-like features appearing as 'double jumps' in the vertical bar del P vertical bar map that are correlated with negative and positive filaments of B-type polarization. These local asymmetries between the two polarization types, E and B, of the non-thermal Galactic synchrotron emission have an influence on the E- and B-mode power spectra analyses. The wavelet-based formalism of the polarization gradient analysis allows us to locate the position of E- or B-mode features responsible for the local asymmetries between the two polarization types. In analysed subregions, the perturbations of the magnetic field are trigged by star clusters associated with HII regions, the Orion-Eridanus superbubble and the North Polar Spur at low Galactic latitude.

Original languageEnglish
Pages (from-to)2957-2974
Number of pages18
JournalMonthly Notices of the Royal Astronomical Society
Volume468
Issue number3
DOIs
Publication statusPublished - Jul 2017

Cite this

Robitaille, J. -F. ; Scaife, A. M. M. ; Carretti, E. ; Gaensler, B. M. ; McEwen, J. D. ; Leistedt, B. ; Haverkorn, M. ; Bernardi, G. ; Kesteven, M. J. ; Poppi, S. ; Staveley-Smith, L. / A new perspective on turbulent Galactic magnetic fields through comparison of linear polarization decomposition techniques. In: Monthly Notices of the Royal Astronomical Society. 2017 ; Vol. 468, No. 3. pp. 2957-2974.
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abstract = "We compare two rotationally invariant decomposition techniques on linear polarization data: the spin-2 spherical harmonic decomposition in two opposite parities, the E- and B-mode, and the multiscale analysis of the gradient of linear polarization, vertical bar del P vertical bar. We demonstrate that both decompositions have similar properties in the image domain and the spatial frequency domain. They can be used as complementary tools for turbulence analysis of interstellar magnetic fields in order to develop a better understanding of the origin of energy sources for the turbulence, the origin of peculiar magnetic field structures and their underlying physics. We also introduce a new quantity vertical bar del EB vertical bar based on the E-and B-modes and we show that in the intermediate-and small-scale limit vertical bar del EB vertical bar similar or equal to vertical bar del P vertical bar. Analysis of the 2.3 GHz S-band Polarization All Sky Survey shows many extended coherent filament-like features appearing as 'double jumps' in the vertical bar del P vertical bar map that are correlated with negative and positive filaments of B-type polarization. These local asymmetries between the two polarization types, E and B, of the non-thermal Galactic synchrotron emission have an influence on the E- and B-mode power spectra analyses. The wavelet-based formalism of the polarization gradient analysis allows us to locate the position of E- or B-mode features responsible for the local asymmetries between the two polarization types. In analysed subregions, the perturbations of the magnetic field are trigged by star clusters associated with HII regions, the Orion-Eridanus superbubble and the North Polar Spur at low Galactic latitude.",
keywords = "techniques: image processing, ISM: general, ISM: magnetic fields, ISM: structure, radio continuum: ISM, DELTA-VARIANCE METHOD, CMB POLARIZATION, INTERSTELLAR TURBULENCE, RADIO-POLARIZATION, MOLECULAR CLOUDS, GRAVITY-WAVES, SOUTHERN SKY, PLANE, GRADIENTS, EMISSION",
author = "Robitaille, {J. -F.} and Scaife, {A. M. M.} and E. Carretti and Gaensler, {B. M.} and McEwen, {J. D.} and B. Leistedt and M. Haverkorn and G. Bernardi and Kesteven, {M. J.} and S. Poppi and L. Staveley-Smith",
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doi = "10.1093/mnras/stx642",
language = "English",
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Robitaille, J-F, Scaife, AMM, Carretti, E, Gaensler, BM, McEwen, JD, Leistedt, B, Haverkorn, M, Bernardi, G, Kesteven, MJ, Poppi, S & Staveley-Smith, L 2017, 'A new perspective on turbulent Galactic magnetic fields through comparison of linear polarization decomposition techniques' Monthly Notices of the Royal Astronomical Society, vol. 468, no. 3, pp. 2957-2974. https://doi.org/10.1093/mnras/stx642

A new perspective on turbulent Galactic magnetic fields through comparison of linear polarization decomposition techniques. / Robitaille, J. -F.; Scaife, A. M. M.; Carretti, E.; Gaensler, B. M.; McEwen, J. D.; Leistedt, B.; Haverkorn, M.; Bernardi, G.; Kesteven, M. J.; Poppi, S.; Staveley-Smith, L.

In: Monthly Notices of the Royal Astronomical Society, Vol. 468, No. 3, 07.2017, p. 2957-2974.

Research output: Contribution to journalArticle

TY - JOUR

T1 - A new perspective on turbulent Galactic magnetic fields through comparison of linear polarization decomposition techniques

AU - Robitaille, J. -F.

AU - Scaife, A. M. M.

AU - Carretti, E.

AU - Gaensler, B. M.

AU - McEwen, J. D.

AU - Leistedt, B.

AU - Haverkorn, M.

AU - Bernardi, G.

AU - Kesteven, M. J.

AU - Poppi, S.

AU - Staveley-Smith, L.

PY - 2017/7

Y1 - 2017/7

N2 - We compare two rotationally invariant decomposition techniques on linear polarization data: the spin-2 spherical harmonic decomposition in two opposite parities, the E- and B-mode, and the multiscale analysis of the gradient of linear polarization, vertical bar del P vertical bar. We demonstrate that both decompositions have similar properties in the image domain and the spatial frequency domain. They can be used as complementary tools for turbulence analysis of interstellar magnetic fields in order to develop a better understanding of the origin of energy sources for the turbulence, the origin of peculiar magnetic field structures and their underlying physics. We also introduce a new quantity vertical bar del EB vertical bar based on the E-and B-modes and we show that in the intermediate-and small-scale limit vertical bar del EB vertical bar similar or equal to vertical bar del P vertical bar. Analysis of the 2.3 GHz S-band Polarization All Sky Survey shows many extended coherent filament-like features appearing as 'double jumps' in the vertical bar del P vertical bar map that are correlated with negative and positive filaments of B-type polarization. These local asymmetries between the two polarization types, E and B, of the non-thermal Galactic synchrotron emission have an influence on the E- and B-mode power spectra analyses. The wavelet-based formalism of the polarization gradient analysis allows us to locate the position of E- or B-mode features responsible for the local asymmetries between the two polarization types. In analysed subregions, the perturbations of the magnetic field are trigged by star clusters associated with HII regions, the Orion-Eridanus superbubble and the North Polar Spur at low Galactic latitude.

AB - We compare two rotationally invariant decomposition techniques on linear polarization data: the spin-2 spherical harmonic decomposition in two opposite parities, the E- and B-mode, and the multiscale analysis of the gradient of linear polarization, vertical bar del P vertical bar. We demonstrate that both decompositions have similar properties in the image domain and the spatial frequency domain. They can be used as complementary tools for turbulence analysis of interstellar magnetic fields in order to develop a better understanding of the origin of energy sources for the turbulence, the origin of peculiar magnetic field structures and their underlying physics. We also introduce a new quantity vertical bar del EB vertical bar based on the E-and B-modes and we show that in the intermediate-and small-scale limit vertical bar del EB vertical bar similar or equal to vertical bar del P vertical bar. Analysis of the 2.3 GHz S-band Polarization All Sky Survey shows many extended coherent filament-like features appearing as 'double jumps' in the vertical bar del P vertical bar map that are correlated with negative and positive filaments of B-type polarization. These local asymmetries between the two polarization types, E and B, of the non-thermal Galactic synchrotron emission have an influence on the E- and B-mode power spectra analyses. The wavelet-based formalism of the polarization gradient analysis allows us to locate the position of E- or B-mode features responsible for the local asymmetries between the two polarization types. In analysed subregions, the perturbations of the magnetic field are trigged by star clusters associated with HII regions, the Orion-Eridanus superbubble and the North Polar Spur at low Galactic latitude.

KW - techniques: image processing

KW - ISM: general

KW - ISM: magnetic fields

KW - ISM: structure

KW - radio continuum: ISM

KW - DELTA-VARIANCE METHOD

KW - CMB POLARIZATION

KW - INTERSTELLAR TURBULENCE

KW - RADIO-POLARIZATION

KW - MOLECULAR CLOUDS

KW - GRAVITY-WAVES

KW - SOUTHERN SKY

KW - PLANE

KW - GRADIENTS

KW - EMISSION

U2 - 10.1093/mnras/stx642

DO - 10.1093/mnras/stx642

M3 - Article

VL - 468

SP - 2957

EP - 2974

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

SN - 0035-8711

IS - 3

ER -