| A Survey of kiloparsec-scale radio outflows in radio-quiet active galactic nuclei (2005) | |||||||||||||||
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| A Survey Kiloparsec Scale Radio Outflows Radio Quiet Active Galactic Nuclei Jack Gallimore Department Physics Astrronomy Bucknell University Lewisburg USA jgallimo bucknell edu David Axon and Christopher Dea Department Physics Rochester Institute Technology Lomb Memorial Drive Rochester Stefi Baum Chester Carlson Center for Imaging Science Rochester Institute Technology Lomb Memorial Drive Rochester Alan Pedlar The University Manchester Jodrell Bank Observatory Macclesfield Cheshire ABSTRACT Seyfert galaxies commonly host compact jets spanning scales but larger structures are resolved out long baseline aperture synthesis surveys Previous targeted studies showed that kiloparsec scale radio structures KSRs may common feature Seyfert and LINER galaxies and the origin KSRs may starburst AGN report new Very Large Array VLA survey complete sample Seyfert and LINER galaxies Out all the surveyed radio quiet sources find that show extended radio structures least kpc total extent that not match the morphology the disk its associated star forming regions The detection rate lower limit owing the combined effects projection and resolution The infrared colors the KSR host galaxies are unremarkable compared other Seyferts and the large scale outflows orient randomly with respect the host galaxy axes The KSR Seyferts instead stand out deviating significantly from the far infrared radio correlation for starforming galaxies with tendency towards radio excess and they are more likely have relat. Seyfert galaxies commonly host compact jets spanning 10—100 pc scales, but larger structures are resolved out in long baseline, aperture synthesis surveys. Previous, targeted studies showed that kiloparsec-scale radio structures (KSRs) may be a common feature of Seyfert and LINER galaxies, and the origin of KSRs may be starburst or AGN. We report a new Very Large Array (VLA) survey of a complete sample of Seyfert and LINER galaxies. Out of all of the surveyed radio-quiet sources, we find that 44% (19 / 43) show extended radio structures at least 1 kpc in total extent that do not match the morphology of the disk or its associated star-forming regions. The detection rate is a lower limit owing to the combined effects of projection and resolution. The infrared colors of the KSR host galaxies are unremarkable compared to other Seyferts, and the large-scale outflows orient randomly with respect to the host galaxy axes. The KSR Seyferts instead stand out by deviating significantly from the far-infrared – radio correlation for starforming galaxies, with tendency towards radio excess, and they are more likely to have a relatively luminous, compact radio source in the nucleus; these results argue that KSRs are powered by the AGN rather than starburst. The high detection rate indicates that Seyferts generate radio outflows over a significant fraction of their lifetime, which is much longer than the dynamical timescale of an AGN-powered jet but comparable instead to the buoyancy timescale. The likely explanation is that the KSRs originate from jet plasma that has been decelerated by interaction with the nuclear ISM. Based on a simple ram pressure argument, the kinetic power of the jet on kiloparsec scales is about three orders of magnitude weaker than the power of the jet on 10—100 pc scales. This result is consistent with the interaction model, in which case virtually all of the jet power must be lost to the ISM within the inner kiloparsec. (Refer to PDF file for exact formulas). | |||||||||||||||
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