CORRELATION BETWEEN EMISSION LINES AND RADIO LUMINOSITIES OF ACTIVE GALACTIC NUCLEI

• Main Author: Short-Long, Jessica
• Format: Others
• Published: UKnowledge 2018
• Subjects: line profiles; radio continuum; galaxies; nuclei; accretion; jets; Astrophysics and Astronomy; External Galaxies; Physical Processes
• Online Access: https://uknowledge.uky.edu/physastron_etds/55; https://uknowledge.uky.edu/cgi/viewcontent.cgi?article=1057&context=physastron_etds

Radio-loud active galactic nuclei (AGN) are one class of objects associated with accretion activity onto supermassive black holes in centers of massive galaxies. They are believed to be in a radiatively-inefficient accretion mode with low accretion rate. To understand this accretion mode, it is important to measure its radiative output at high energies (> 13.6eV), which can be traced through optical emission lines. However, little is known about their true radiative output. This is because no correlation between optical emission-line and radio luminosity has been found for the majority of low-luminosity radio AGN, which are often classified as low-excitation radio galaxies, or Fanaroff-Riley Class I (FR-I) radio galaxies. We demonstrate that most of the line emission found in these galaxies is not powered by the central AGN, but likely powered by some old stellar population. Only when this component is subtracted or otherwise taken into account can we estimate the true line emission associated with the AGN. These emissions may show interesting correlations with the radio luminosities in some cases.