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dc.contributor.authorStawarz, L.
dc.contributor.authorTanaka, Y. T.
dc.contributor.authorMadejski, G.
dc.contributor.authorO'Sullivan, S. P.
dc.contributor.authorCheung, C. C.
dc.contributor.authorFeain, I.J.
dc.contributor.authorFukazawa, Y.
dc.contributor.authorGandhi, P.
dc.contributor.authorHardcastle, M.J.
dc.contributor.authorKataoka, J.
dc.contributor.authorOstrowski, M.
dc.contributor.authorReville, B.
dc.contributor.authorSiemiginowska, A.
dc.contributor.authorSimionescu, A.
dc.contributor.authorTakahashi, T.
dc.contributor.authorTakei, Y.
dc.contributor.authorTakeuchi, Y.
dc.contributor.authorWerner, N.
dc.date.accessioned2013-06-05T07:15:52Z
dc.date.available2013-06-05T07:15:52Z
dc.date.issued2013-03-20
dc.identifier.citationStawarz , L , Tanaka , Y T , Madejski , G , O'Sullivan , S P , Cheung , C C , Feain , I J , Fukazawa , Y , Gandhi , P , Hardcastle , M J , Kataoka , J , Ostrowski , M , Reville , B , Siemiginowska , A , Simionescu , A , Takahashi , T , Takei , Y , Takeuchi , Y & Werner , N 2013 , ' Giant lobes of Centaurus A radio galaxy observed with the Suzaku X-ray satellite ' , The Astrophysical Journal , vol. 766 , no. 1 , 48 . https://doi.org/10.1088/0004-637X/766/1/48
dc.identifier.issn0004-637X
dc.identifier.otherPURE: 1800230
dc.identifier.otherPURE UUID: 108fe1b2-75ae-4d36-b93d-440db93047cb
dc.identifier.otherWOS: 000316054000048
dc.identifier.otherScopus: 84875001400
dc.identifier.urihttp://hdl.handle.net/2299/10697
dc.description.abstractWe report on Suzaku observations of selected regions within the southern giant lobe of the radio galaxy Centaurus A. In our analysis we focus on distinct X-ray features detected with the X-ray Imaging Spectrometer within the range 0.5-10 keV, some of which are likely associated with fine structure of the lobe revealed by recent high-quality radio intensity and polarization maps. With the available photon statistics, we find that the spectral properties of the detected X-ray features are equally consistent with thermal emission from hot gas with temperatures kT > 1 keV, or with a power-law radiation continuum characterized by photon indices Gamma similar to 2.0 +/- 0.5. However, the plasma parameters implied by these different models favor a synchrotron origin for the analyzed X-ray spots, indicating that a very efficient acceleration of electrons up to greater than or similar to 10 TeV energies is taking place within the giant structure of Centaurus A, albeit only in isolated and compact regions associated with extended and highly polarized radio filaments. We also present a detailed analysis of the diffuse X-ray emission filling the whole field of view of the instrument, resulting in a tentative detection of a soft excess component best fitted by a thermal model with a temperature of kT similar to 0.5 keV. The exact origin of the observed excess remains uncertain, although energetic considerations point to thermal gas filling the bulk of the volume of the lobe and mixed with the non-thermal plasma, rather than to the alternative scenario involving a condensation of the hot intergalactic medium around the edges of the expanding radio structure. If correct, this would be the first detection of the thermal content of the extended lobes of a radio galaxy in X-rays. The corresponding number density of the thermal gas in such a case is n(g) similar to 10(-4) cm(-3), while its pressure appears to be in almost exact equipartition with the volume-averaged non-thermal pressure provided by the radio-emitting electrons and the lobes' magnetic field. A prominent large-scale fluctuation of the Galactic foreground emission, resulting in excess foreground X-ray emission aligned with the lobe, cannot be ruled out. Although tentative, our findings potentially imply that the structure of the extended lobes in active galaxies is likely to be highly inhomogeneous and non-uniform, with magnetic reconnection and turbulent acceleration processes continuously converting magnetic energy to internal energy of the plasma particles, leading to possibly significant spatial and temporal variations in the plasma beta parameter around the volume-averaged equilibrium condition beta similar to 1.en
dc.format.extent19
dc.language.isoeng
dc.relation.ispartofThe Astrophysical Journal
dc.rightsOpen
dc.subjectNUMBER COUNTS
dc.subjectgalaxies: individual (Centaurus A)
dc.subjectFERMI-LAT
dc.subjectgalaxies: jets
dc.subjectPARTICLE-ACCELERATION
dc.subjectX-rays: galaxies
dc.subjectENERGY COSMIC-RAYS
dc.subjectDEEP FIELD-SOUTH
dc.subjectDOUBLE-DOUBLE MORPHOLOGY
dc.subjectACTIVE GALACTIC NUCLEI
dc.subjectgalaxies: active
dc.subjectMAGNETIC-FIELD
dc.subjectHOT-SPOTS
dc.subjectmagnetic fields
dc.subjectCENTER REGION
dc.subjectintergalactic medium
dc.titleGiant lobes of Centaurus A radio galaxy observed with the Suzaku X-ray satelliteen
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.versiontypeSubmitted Version
dcterms.dateAccepted2013-03-20
rioxxterms.versionSMUR
rioxxterms.versionofrecordhttps://doi.org/10.1088/0004-637X/766/1/48
rioxxterms.typeJournal Article/Review
herts.preservation.rarelyaccessedtrue
herts.rights.accesstypeOpen


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