Show simple item record

dc.contributor.authorTadhunter, C.N.
dc.contributor.authorSparks, W.
dc.contributor.authorAxon, D.J.
dc.contributor.authorBergeron, L.
dc.contributor.authorJackson, N.
dc.contributor.authorPackham, C.
dc.contributor.authorHough, J.
dc.contributor.authorRobinson, A.
dc.contributor.authorYoung, S.
dc.date.accessioned2008-01-25T10:11:55Z
dc.date.available2008-01-25T10:11:55Z
dc.date.issued2000
dc.identifier.citationTadhunter , C N , Sparks , W , Axon , D J , Bergeron , L , Jackson , N , Packham , C , Hough , J , Robinson , A & Young , S 2000 , ' Highly polarized structures in the near-nuclear regions of Cygnus A: intrinsic anisotropy within the cones ' , Monthly Notices of the Royal Astronomical Society , vol. 313 , no. 4 , pp. L52L56 . https://doi.org/10.1046/j.1365-8711.2000.03442.x
dc.identifier.issn0035-8711
dc.identifier.otherPURE: 142534
dc.identifier.otherPURE UUID: df5f564e-cb00-443f-b512-6aeb9f24e413
dc.identifier.otherdspace: 2299/1397
dc.identifier.otherScopus: 0037957397
dc.identifier.urihttp://hdl.handle.net/2299/1397
dc.descriptionThe definitive version is available at www.blackwell-synergy.com. Copyright Blackwell Publishing DOI : 10.1046/j.1365-8711.2000.03442.x
dc.description.abstractWe present near-IR imaging polarimetry observations of the nucleus of Cygnus A, taken with the NICMOS camera of the HST at a wavelength of 2.0μm. These maps reveal a highly collimated region of polarized emission straddling the nucleus and extending to a radius of 1.2 arcseconds. Remarkably, this feature coincides with one, but only one, limb of the edge-brightened bicone structure seen in the total intensity image. The high degree (Pk ~25%) and orientation of the extended polarization feature are consistent with a scattering origin. Most plausibly, the detection of polarization along only one limb of the bicone is a consequence of intrinsic anisotropy of the near-IR continuum within the radiation cones, with the direction of maximum intensity of the near-IR radiation field significantly displaced from the direction of the radio axis. The unresolved nuclear core source is also highly polarized (Pk > 28%), with a position angle close to the perpendicular to the radio axis. Given that this high degree of nuclear polarization can only be explained in terms of dichroic extinction if the dichroic mechanism is unusually efficient in Cygnus A, it is more likely that the nuclear polarization is due to the scattering of nuclear light in an unresolved scattering region close to the AGN. In this case, the flux of the core source in the K-band is dominated by scattered rather than transmitted quasar light, and previous extinction estimates based on K-band photometry of the core substantially underestimate the true nuclear extinction.en
dc.language.isoeng
dc.relation.ispartofMonthly Notices of the Royal Astronomical Society
dc.rightsOpen
dc.titleHighly polarized structures in the near-nuclear regions of Cygnus A: intrinsic anisotropy within the conesen
dc.contributor.institutionSchool of Physics, Astronomy and Mathematics
dc.description.statusPeer reviewed
dc.relation.schoolSchool of Physics, Astronomy and Mathematics
dcterms.dateAccepted2000
rioxxterms.versionofrecordhttps://doi.org/10.1046/j.1365-8711.2000.03442.x
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue
herts.rights.accesstypeOpen


Files in this item

Thumbnail

This item appears in the following Collection(s)

Show simple item record