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dc.contributor.authorKrause, Martin G. H.
dc.contributor.authorHardcastle, Martin J.
dc.date.accessioned2021-02-06T00:07:00Z
dc.date.available2021-02-06T00:07:00Z
dc.date.issued2021-04-01
dc.identifier.citationKrause , M G H & Hardcastle , M J 2021 , ' Can the Local Bubble explain the radio background? ' , Monthly Notices of the Royal Astronomical Society , vol. 502 , no. 2 , stab131 , pp. 2807-2814 . https://doi.org/10.1093/mnras/stab131
dc.identifier.issn0035-8711
dc.identifier.otherPURE: 24360658
dc.identifier.otherPURE UUID: 16cf295f-71da-42c2-8238-e74db46fedda
dc.identifier.otherArXiv: http://arxiv.org/abs/2101.05255v1
dc.identifier.otherScopus: 85104096170
dc.identifier.otherORCID: /0000-0002-9610-5629/work/116555524
dc.identifier.urihttp://hdl.handle.net/2299/23861
dc.descriptionCopyright 2021 The Author(s). Published by Oxford University Press on behalf of Royal Astronomical Society. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
dc.description.abstractThe ARCADE 2 balloon bolometer along with a number of other instruments have detected what appears to be a radio synchrotron background at frequencies below about 3 GHz. Neither extragalactic radio sources nor diffuse Galactic emission can currently account for this finding. We use the locally measured cosmic ray electron population, demodulated for effects of the Solar wind, and other observational constraints combined with a turbulent magnetic field model to predict the radio synchrotron emission for the Local Bubble. We find that the spectral index of the modelled radio emission is roughly consistent with the radio background. Our model can approximately reproduce the observed antenna temperatures for a mean magnetic field strength B between 3 and 5 nT. We argue that this would not violate observational constraints from pulsar measurements. However, the curvature in the predicted spectrum would mean that other, so far unknown sources would have to contribute below 100 MHz. Also, the magnetic energy density would then dominate over thermal and cosmic ray electron energy density, likely causing an inverse magnetic cascade with large variations of the radio emission in different sky directions as well as high polarization. We argue that this disagrees with several observations and thus that the magnetic field is probably much lower, quite possibly limited by equipartition with the energy density in relativistic or thermal particles (B = 0.2-0.6 nT). In the latter case, we predict a contribution of the Local Bubble to the unexplained radio background at most at the per cent level.en
dc.format.extent8
dc.language.isoeng
dc.relation.ispartofMonthly Notices of the Royal Astronomical Society
dc.subjectastro-ph.HE
dc.subjectastro-ph.GA
dc.subjectdiffuse radiation
dc.subjectISM: bubbles
dc.subjectradio continuum: ISM
dc.subjectradio continuum: general
dc.subjectlocal interstellar matter
dc.subjectAstronomy and Astrophysics
dc.subjectSpace and Planetary Science
dc.titleCan the Local Bubble explain the radio background?en
dc.contributor.institutionCentre for Astrophysics Research
dc.contributor.institutionSchool of Physics, Engineering & Computer Science
dc.contributor.institutionDepartment of Physics, Astronomy and Mathematics
dc.contributor.institutionSPECS Deans Group
dc.description.statusPeer reviewed
dc.identifier.urlhttp://www.scopus.com/inward/record.url?scp=85104096170&partnerID=8YFLogxK
rioxxterms.versionVoR
rioxxterms.versionofrecordhttps://doi.org/10.1093/mnras/stab131
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue


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