NASA/IPAC EXTRAGALACTIC DATABASE
Date and Time of the Query: 2019-08-24 T01:23:39 PDT
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For refcode 2001ApJ...559L..87N:
Retrieve 16 NED objects in this reference.
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2001ApJ...559L..87N Evidence for Jet Domination of the Nuclear Radio Emission in Low-Luminosity Active Galactic Nuclei Neil M. Nagar, Andrew S. Wilson, and Heino Falcke Received 2001 June 28; accepted 2001 August 21; published 2001 September 7 ABSTRACT We present simultaneous, subarcsecond (<=50 pc) resolution 5, 8.4, and 15 GHz Very Large Array observations of a well-defined sample of 16 low-luminosity active galactic nuclei. The radio emission in most of these nuclei does not show the rising spectrum (0.2 <~ s <~ 1.3, L_{nu}_ is proportional to {nu}^s^) expected from thermal electrons in an advection-dominated accretion flow (ADAF) with or without weak to moderately strong outflows. Rather, the flat radio spectra are indicative of either synchrotron self-absorbed emission from jets, convection-dominated accretion flows (CDAFs) with L >~ 10^-5^L_Edd_, or ADAFs with strong (p >~ 0.6) outflows. The jet interpretation is favored by three factors: (1) the detection of parsec-scale radio extensions, morphologically reminiscent of jets, in the five nuclei with the highest peak radio flux density, (2) the domination of parsec-scale jet radio emission over unresolved "core" emission in the three best-studied nuclei, and (3) the lack of any clear correlation between radio spectral shape and black hole mass as would be expected from the dependence of the radio turnover frequency on black hole mass in ADAF and CDAF models. A jet domination of nuclear radio emission implies significantly lower accretion rates in ADAF-type models than earlier estimated from core radio luminosities. Subject headings: accretion, accretion disks - galaxies: active - galaxies: jets - galaxies: nuclei - radio continuum: galaxies - surveys
Retrieve 16 NED objects in this reference.
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