Journal article

Radio-excess IRAS galaxies. IV. Optical spectroscopy

Catherine L Buchanan, Peter J McGregor, Geoffrey V Bicknell, Michael A Dopita

ASTRONOMICAL JOURNAL | UNIV CHICAGO PRESS | Published : 2006

Abstract

This is the fourth in our series of papers discussing the nature of radio-excess galaxies, which have radio emission associated with an active nucleus but do not fit into the traditional categories of either radio-loud or radio-quiet active galaxies. In this paper we present optical spectra of our sample of far-infrared (FIR)-luminous radio-excess galaxies. Optical emission-line ratio diagnostics are used to determine the dominant source of the ionizing radiation. We find that radio excess is an excellent indicator of the presence of an active nucleus. The radio-excess sample contains a much higher fraction of active galactic nuclei (AGNs) than samples selected on FIR luminosity alone or usi..

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University of Melbourne Researchers