The magnetic field strength of the Faraday screen surrounding the radio galaxy Coma A

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dc.contributor.authorKnuettel, Sebastian
dc.contributor.authorO'Sullivan, S. P.
dc.contributor.authorCuriel, S.
dc.contributor.authorEmonts, B. H. C.
dc.contributor.funderIrish Research Councilen
dc.contributor.funderDeutsche Forschungsgemeinschaften
dc.contributor.funderUniversidad Nacional Autónoma de Méxicoen
dc.date.accessioned2019-05-21T14:32:28Z
dc.date.available2019-05-21T14:32:28Z
dc.date.issued2018-11-10
dc.date.updated2019-05-21T14:20:20Z
dc.description.abstractStudying the interaction between AGN jets and lobes and their surrounding environment is important in order to understand how they transfer energy to their environment as well as determining the intrinsic physical properties of the sources themselves. This paper presents broad-band VLA polarization and Faraday rotation observations of the radio galaxy Coma A (3C 277.3) from 1 to 4 GHz, including archival VLA observations at 4.9 and 15 GHz. Through broad-band polarization model-fitting, we find that an external Faraday screen with a turbulent magnetic field provides an appropriate description to most of the data. By combining the polarization and Faraday rotation results with previous H  α observations, we identified the H α-emitting gas as the Faraday screen responsible for the observed Faraday depolarization. We were able to derive the magnetic field strength in the H α-emitting gas, finding typical field strengths of ∼1 μG, which is consistent with studies of the intragroup medium local to other radio galaxies. However, we find a highly depolarized region of the southern lobe coincident with a H α filament that has a field strength comparable to the equipartition field strength in the radio lobe (i.e. ≳36 μG). This implies that the H α filament is internal to the radio emitting plasma. Such clear examples of internal Faraday depolarization are rare, thus providing another key insight into the evolution of radio galaxies and their ability to provide significant feedback on the local gas that would otherwise cool and form stars.en
dc.description.sponsorshipIrish Research Council (Government of Ireland Postgraduate Programme); Deutsche Forschungsgemeinschaft (Grant BR2026/23); Universidad Nacional Autónoma de México (PAPIIT project IA103416)en
dc.description.statusPeer revieweden
dc.description.versionPublished Versionen
dc.format.mimetypeapplication/pdfen
dc.identifier.citationKnuettel, S., O'Sullivan, S. P., Curiel, S. and Emonts, B. H. C. (2018) 'The magnetic field strength of the Faraday screen surrounding the radio galaxy Coma A', Monthly Notices of the Royal Astronomical Society, 482(4), pp. 4606-4616. doi: 10.1093/mnras/sty3018en
dc.identifier.doi10.1093/mnras/sty3018en
dc.identifier.eissn1365-2966
dc.identifier.endpage4616en
dc.identifier.issn0035-8711
dc.identifier.issued4en
dc.identifier.journaltitleMonthly Notices of The Royal Astronomical Societyen
dc.identifier.startpage4606en
dc.identifier.urihttps://hdl.handle.net/10468/7954
dc.identifier.volume482en
dc.language.isoenen
dc.publisherOxford University Pressen
dc.rights© 2018, the Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.en
dc.subjectPolarimetricen
dc.subjectActive galaxiesen
dc.subjectComa Aen
dc.subjectRadio continuumen
dc.subjectFaraday screenen
dc.subjectRadio galaxyen
dc.subjectMagnetic fielden
dc.titleThe magnetic field strength of the Faraday screen surrounding the radio galaxy Coma Aen
dc.typeArticle (peer-reviewed)en
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