Magnetic field strength and spectral distribution of six parsec-scale active galactic nuclei jets

Show simple item record O'Sullivan, S. P. Gabuzda, Denise 2017-11-07T09:38:55Z 2017-11-07T09:38:55Z 2009
dc.identifier.citation O'Sullivan, S. P. and Gabuzda, D. C. (2009) 'Magnetic field strength and spectral distribution of six parsec-scale active galactic nuclei jets', Monthly Notices of the Royal Astronomical Society, 400(1), pp. 26-42. doi: 10.1111/j.1365-2966.2009.15428.x en
dc.identifier.volume 400
dc.identifier.issued 1
dc.identifier.startpage 26
dc.identifier.endpage 42
dc.identifier.issn 0035-8711
dc.identifier.doi 10.1111/j.1365-2966.2009.15428.x
dc.description.abstract We use observations of six 'blazars' with the Very Long Baseline Array (VLBA), at eight frequencies (4.6, 5.1, 7.9, 8.9, 12.9, 15.4, 22.2 and 43.1 GHz), to investigate the frequency-dependent position of their VLBI cores ('core-shift') and their overall jet spectral distribution. By cross-correlating the optically thin jet emission, we are able to accurately align the multifrequency images of three of the jets (1418+546, 2007+777, 2200+420), whose core-shifts and spectra we find consistent with the equipartition regime of the Blandford & Konigl conical jet model, where the position of the radio core from the base of the jet follows r(core)(nu) proportional to nu-1. For the jet of 0954+658, we align the higher frequency images using our lower frequency measurements assuming equipartition in the radio core from 4.6-43 GHz. The jet emission of the other two sources in our sample (1156+295, 1749+096) is too sparse for our alignment technique to work. Using our measured core-shifts, we calculate equipartition magnetic field strengths of the order of 10s to 100s of mG in the radio cores of these four AGN from 4.6-43 GHz. Extrapolating our results back to the accretion disc and black hole jet-launching distances, we find magnetic field strengths consistent with those expected from theoretical models of magnetically powered jets. en
dc.format.mimetype application/pdf en
dc.language.iso en en
dc.publisher Oxford University Press en
dc.rights © 2009, the Authors. Journal compilation © 2009, RAS en
dc.subject Galaxies en
dc.subject Jets en
dc.subject Magnetic fields en
dc.subject Radio continuum en
dc.title Magnetic field strength and spectral distribution of six parsec-scale active galactic nuclei jets en
dc.type Article (peer-reviewed) en
dc.internal.authorcontactother Shane O'Sullivan, Physics, University College Cork, Cork, Ireland. +353-21-490-3000 en
dc.internal.availability Full text available en
dc.description.version Published Version en
dc.contributor.funder Irish Research Council for Science, Engineering and Technology
dc.description.status Peer reviewed en
dc.identifier.journaltitle Monthly Notices of the Royal Astronomical Society en
dc.internal.IRISemailaddress en

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