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Main Authors: Forster, Bailey, Foster, Tyler J., Kothes, Roland, Hill, Alex S., Brown, Jo-Anne
Format: Preprint
Published: 2024
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Online Access:https://arxiv.org/abs/2411.08978
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author Forster, Bailey
Foster, Tyler J.
Kothes, Roland
Hill, Alex S.
Brown, Jo-Anne
author_facet Forster, Bailey
Foster, Tyler J.
Kothes, Roland
Hill, Alex S.
Brown, Jo-Anne
contents Observations of the Milky Way and external galaxies support the idea that large-scale magnetic fields are concentrated in galactic disks, with halo magnetic fields at least an order of magnitude weaker. However, very little is known about the transition between the two. We present the discovery of linearly polarized radio emission at the interface between interacting shells of gas within a well-known grouping of high-velocity clouds (HVCs), the Anti-Center Shell. Faraday rotation of diffuse emission and of background extragalactic compact sources demonstrates an enhancement of the field at the interface. This is the clearest observed example of an HVC altering the large-scale magnetic field at the disk-halo interface and is the first image of magnetic field effects in an HVC. These results demonstrate the possibility of future three-dimensional reconstruction of the Galactic magnetic field and showcase the versatility of the Synthesis Telescope at the Dominion Radio Astrophysical Observatory as one of the few existing telescopes which can exploit this new method of probing Galactic magnetism.
format Preprint
id arxiv_https___arxiv_org_abs_2411_08978
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Interaction Between Rogue HI Clouds and the Magnetic Field High Above the Galaxy
Forster, Bailey
Foster, Tyler J.
Kothes, Roland
Hill, Alex S.
Brown, Jo-Anne
Astrophysics of Galaxies
Observations of the Milky Way and external galaxies support the idea that large-scale magnetic fields are concentrated in galactic disks, with halo magnetic fields at least an order of magnitude weaker. However, very little is known about the transition between the two. We present the discovery of linearly polarized radio emission at the interface between interacting shells of gas within a well-known grouping of high-velocity clouds (HVCs), the Anti-Center Shell. Faraday rotation of diffuse emission and of background extragalactic compact sources demonstrates an enhancement of the field at the interface. This is the clearest observed example of an HVC altering the large-scale magnetic field at the disk-halo interface and is the first image of magnetic field effects in an HVC. These results demonstrate the possibility of future three-dimensional reconstruction of the Galactic magnetic field and showcase the versatility of the Synthesis Telescope at the Dominion Radio Astrophysical Observatory as one of the few existing telescopes which can exploit this new method of probing Galactic magnetism.
title Interaction Between Rogue HI Clouds and the Magnetic Field High Above the Galaxy
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2411.08978