COLA II - Radio and Spectroscopic Diagnostics of Nuclear Activity in Galaxies

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dc.creatorCorbett, E. A.
dc.creatorKewley, L. J.
dc.creatorAppleton, P. N.
dc.creatorCharmandaris, V.
dc.creatorDopita, M. A.
dc.creatorHeisler, C. A.
dc.creatorNorris, R. P.
dc.creatorZezas, A.
dc.creatorMarston, A.
dc.date2002-10-09
dc.date.accessioned2026-07-07T10:31:24Z
dc.date.available2026-07-07T10:31:24Z
dc.descriptionWe present optical spectroscopic observations of 93 galaxies taken from the infra-red selected COLA (Compact Objects in Low Power AGN) sample. The sample spans the range of far-IR luminosities from normal galaxies to LIRGs. Of the galaxies observed, 78 (84%) exhibit emission lines. Using a theoretically-based optical emission-line scheme we classify 15% of the emission-line galaxies as Seyferts, 77% as starbursts, and the rest are either borderline AGN/starburst or show ambiguous characteristics. We find little evidence for an increase in the fraction of AGN in the sample as a function of far-IR luminosity but our sample covers only a small range in infrared luminosity and thus a weak trend may be masked. As a whole the Seyfert galaxies exhibit a small, but significant, radio excess on the radio-FIR correlation compared to the galaxies classified as starbursts. Compact (<0.05'') radio cores are detected in 55% of the Seyfert galaxies, and these galaxies exhibit a significantly larger radio excess than the Seyfert galaxies in which cores were not detected. Our results indicate that there may be two distinct populations of Seyferts, ``radio-excess'' Seyferts, which exhibit extended radio structures and compact radio cores, and ``radio-quiet'' Seyferts, in which the majority of the radio emission can be attributed to star-formation in the host galaxy. No significant difference is seen between the IR and optical spectroscopic properties of Seyferts with and without radio cores. (Abridged)
dc.description24 pages, 4 figures, 6 tables. Accepted for publication in ApJ, February 2003
dc.identifierhttps://arxiv.org/abs/astro-ph/0210197
dc.identifierhttp://arxiv.org/abs/astro-ph/0210197
dc.identifierAstrophys.J.583:670-688,2003
dc.identifierdoi:10.1086/345414
dc.identifier.urihttp://salesiana.dossiersoluciones.com/handle/123456789/178396
dc.subjectAstrophysics
dc.titleCOLA II - Radio and Spectroscopic Diagnostics of Nuclear Activity in Galaxies
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