dc.contributor.author | Evans, D.A. | |
dc.contributor.author | Hardcastle, M.J. | |
dc.contributor.author | Croston, J.H. | |
dc.date.accessioned | 2008-06-27T14:12:25Z | |
dc.date.available | 2008-06-27T14:12:25Z | |
dc.date.issued | 2008 | |
dc.identifier.citation | Evans , D A , Hardcastle , M J & Croston , J H 2008 , X-Ray Nuclei in Radio Galaxies: Exploring the Roles of Hot and Cold Gas Accretion . in In: Extragalactic Jets: Theory and Observation from Radio to Gamma Ray - ASP Conf Series 386 . Astronomical Society of the Pacific , pp. 161-168 . | |
dc.identifier.isbn | 978-1-58381-336-2 | |
dc.identifier.isbn | 978-1-58381-335-5 | |
dc.identifier.other | dspace: 2299/2136 | |
dc.identifier.other | ORCID: /0000-0003-4223-1117/work/30391046 | |
dc.identifier.uri | http://hdl.handle.net/2299/2136 | |
dc.description | Original paper can be found at: http://www.astrosociety.org/pubs/cs/381.html Copyright ASP | |
dc.description.abstract | We present results from Chandra and XMM-Newton spectroscopic observations of the nuclei of z < 0.5 radio galaxies and quasars from the 3CRR catalog, and examine in detail the dichotomy in the properties of low- and high-excitation radio galaxies. The X-ray spectra of low-excitation sources (those with weak or absent optical emission lines) are dominated by unabsorbed emission from a parsec-scale jet, with no contribution from accretion-related emission. These sources show no evidence for an obscuring torus, and are likely to accrete in a radiatively inefficient manner. High-excitation sources (those with prominent optical emission lines), on the other hand, show a significant contribution from a radiatively efficient accretion disk, which is heavily absorbed in the X-ray when they are oriented close to edge-on with respect to the observer. However, the low-excitation/high-excitation division does not correspond to the FRI/FRII division: thus the Fanaroff-Riley dichotomy remains a consequence of the interaction between the jet and the hot-gas environment through which it propagates. Finally, we suggest that accretion of the hot phase of the IGM is sufficient to power all low-excitation radio sources, while high-excitation sources require an additional contribution from cold gas that in turn forms the cold disk and torus. This model explains a number of properties of the radio-loud active galaxy population, and has important implications for AGN feedback mechanisms. | en |
dc.format.extent | 265511 | |
dc.language.iso | eng | |
dc.publisher | Astronomical Society of the Pacific | |
dc.relation.ispartof | In: Extragalactic Jets: Theory and Observation from Radio to Gamma Ray - ASP Conf Series 386 | |
dc.title | X-Ray Nuclei in Radio Galaxies: Exploring the Roles of Hot and Cold Gas Accretion | en |
dc.contributor.institution | School of Physics, Astronomy and Mathematics | |
dc.contributor.institution | SPECS Deans Group | |
dc.contributor.institution | School of Physics, Engineering & Computer Science | |
dc.contributor.institution | Department of Physics, Astronomy and Mathematics | |
dc.contributor.institution | Centre for Astrophysics Research (CAR) | |
dc.contributor.institution | Science & Technology Research Institute | |
rioxxterms.type | Other | |
herts.preservation.rarelyaccessed | true | |