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dc.contributor.authorWykes, S.
dc.contributor.authorCroston, J.H.
dc.contributor.authorHardcastle, M.J.
dc.contributor.authorEilek, J.A.
dc.contributor.authorBiermann, P.L.
dc.contributor.authorAchterberg, A.
dc.contributor.authorBray, J.D.
dc.contributor.authorLazarian, A.
dc.contributor.authorHaverkorn, M.
dc.contributor.authorProtheroe, R.J.
dc.contributor.authorBromberg, O.
dc.date.accessioned2014-01-13T10:00:38Z
dc.date.available2014-01-13T10:00:38Z
dc.date.issued2013-10
dc.identifier.citationWykes , S , Croston , J H , Hardcastle , M J , Eilek , J A , Biermann , P L , Achterberg , A , Bray , J D , Lazarian , A , Haverkorn , M , Protheroe , R J & Bromberg , O 2013 , ' Mass entrainment and turbulence-driven acceleration of ultra-high energy cosmic rays in Centaurus A ' , Astronomy and Astrophysics , vol. 558 , A19 . https://doi.org/10.1051/0004-6361/201321622
dc.identifier.issn0004-6361
dc.identifier.otherPURE: 2672981
dc.identifier.otherPURE UUID: ea11f131-e200-4a54-a99c-42fc215d3399
dc.identifier.otherScopus: 84885069232
dc.identifier.urihttp://hdl.handle.net/2299/12519
dc.description.abstractObservations of the FR I radio galaxy Centaurus A in radio, X-ray, and gamma-ray bands provide evidence for lepton acceleration up to several TeV and clues about hadron acceleration to tens of EeV. Synthesising the available observational constraints on the physical conditions and particle content in the jets, inner lobes and giant lobes of Centaurus A, we aim to evaluate its feasibility as an ultra-high-energy cosmic-ray source. We apply several methods of determining jet power and affirm the consistency of various power estimates of ~1 × 10 erg s. Employing scaling relations based on previous results for 3C 31, we estimate particle number densities in the jets, encompassing available radio through X-ray observations. Our model is compatible with the jets ingesting ~3 × 10 g s of matter via external entrainment from hot gas and ~7 × 10 g s via internal entrainment from jet-contained stars. This leads to an imbalance between the internal lobe pressure available from radiating particles and magnetic field, and our derived external pressure. Based on knowledge of the external environments of other FR I sources, we estimate the thermal pressure in the giant lobes as 1.5 × 10 dyn cm , from which we deduce a lower limit to the temperature of ~1.6 × 10 K. Using dynamical and buoyancy arguments, we infer ~440-645 Myr and ~560 Myr as the sound-crossing and buoyancy ages of the giant lobes respectively, inconsistent with their spectral ages. We re-investigate the feasibility of particle acceleration via stochastic processes in the lobes, placing new constraints on the energetics and on turbulent input to the lobes. The same "very hot" temperatures that allow self-consistency between the entrainment calculations and the missing pressure also allow stochastic UHECR acceleration models to work.en
dc.format.extent13
dc.language.isoeng
dc.relation.ispartofAstronomy and Astrophysics
dc.rightsOpen
dc.titleMass entrainment and turbulence-driven acceleration of ultra-high energy cosmic rays in Centaurus Aen
dc.contributor.institutionSchool of Physics, Astronomy and Mathematics
dc.contributor.institutionScience & Technology Research Institute
dc.contributor.institutionCentre for Astrophysics Research
dc.description.statusPeer reviewed
dc.relation.schoolSchool of Physics, Astronomy and Mathematics
dc.description.versiontypeFinal Accepted Version
dcterms.dateAccepted2013-10
rioxxterms.versionAM
rioxxterms.versionofrecordhttps://doi.org/10.1051/0004-6361/201321622
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue
herts.rights.accesstypeOpen


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