Magnetically aligned straight depolarisation canals and the rolling Hough transform

Abstract

Aims. We aim to characterize the properties of the straight depolarization canals detected in the Low Frequency Array (LOFAR) polarimetric observations of a field centered on the extragalactic source 3C 196. We also compare the canal orientations with magnet- ically aligned Hi filaments and the magnetic field probed by polarized dust emission. Methods. We used the rolling Hough transform (RHT) to identify and characterize the orientation of the straight depolarization canals in radio polarimetric data and the filaments in Hi data. Results. The majority of the straight depolarization canals and the Hi filaments are inclined by 10deg with respect to the Galactic plane and are aligned with the plane-of-sky magnetic field orientation probed by the Planck dust polarization data. The other distinct orientation, of 65deg with respect to the Galactic plane, is associated with the orientation of a bar-like structure observed in the 3C 196 field at 350 MHz. Conclusions. An alignment between three distinct tracers of the (local) interstellar medium (ISM) suggests that an ordered magnetic field plays a crucial role in confining different ISM phases. The majority of the straight depolarization canals are a result of a projection of the complicated 3D distribution of the ISM. The RHT analysis is a robust method for identifying and characterizing the straight depolarization canals observed in radio-polarimetric data.

arXiv comment6 pages, 5 figures, accepted for publication in A&A

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• A VLA Polarimetric Study of the Galactic Center Radio Arc: Characterizing Polarization, Rotation Measure, and Magnetic Field Properties
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• The multiphase and magnetized neutral hydrogen seen by LOFAR
• First look at the multiphase interstellar medium with synthetic observations of low-frequency Faraday tomography
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• Turbulent power distribution in the local interstellar medium
• Filamentary Dust Polarization and the Morphology of Neutral Hydrogen Structures
• Magnetic field tomography in two clouds towards Ursa Major using HI fibers
• Faraday tomography of LoTSS-DR2 data: II. Multi-tracer analysis in the high-latitude outer Galaxy
• HI filaments as potential compass needles? Comparing the magnetic field structure of the Small Magellanic Cloud to the orientation of GASKAP-HI filaments
• LOFAR Deep Fields: Probing faint Galactic polarised emission in ELAIS-N1
• A Comparison of Multi-Phase Magnetic Field Tracers in a High-Galactic Latitude Region of the Filamentary Interstellar Medium
• The two tails of PSR J2055+2539 as seen by Chandra: analysis of the nebular morphology and pulsar proper motion
• The physical and the geometrical properties of simulated cold HI structures
• The Orion-Taurus ridge: a synchrotron radio loop at the edge of the Orion-Eridanus superbubble
• Associating LOFAR Galactic Faraday structures with the warm neutral medium
• A new analytical model of the cosmic-ray energy flux for Galactic diffuse radio emission
• An origin of narrow extended structure in the interstellar medium: an interstellar contrail created by a fast-moving massive object
• Modeling Local Bubble analogs II: Synthetic Faraday rotation maps
• The contribution of neutral gas to Faraday tomographic data at low frequencies. A first extensive comparison between real and synthetic data
• Multi-tracer analysis of straight depolarisation canals in the surroundings of the 3C 196 field