Vol 5, No 5

Radio Identifications of Markarian Galaxies and the Correlation between Radio and Far-Infrared Properties

Shao-Guang Luo, Xue-Bing Wu

Abstract

Abstract By checking DSS optical images and NVSS radio images, 782 Markarian galaxies were identified to be NVSS radio sources. A comparison of the radio luminosity at 1.4 GHz and the far-infrared (FIR) luminosity for 468 ``normal" galaxies shows a tight correlation. Most of the Seyfert galaxies and quasars follow the radio-FIR relation deduced from the ``normal" galaxy sample, but with a somewhat larger scatter. A total 167 Markarian galaxies, comprising 100 ``normal" galaxies, 66 Seyfert galaxies and one quasar, have either excess radio emission or much lower FIR spectral index α (25μm, 60μm). These galaxies may be classified as ``AGN-powered". For ``normal" galaxies, the average q value (defined as the log ratio between FIR and radio luminosities) is 2.3. There seems a trend for q to slightly decrease with increasing radio luminosity. This may imply that the ongoing active star formation in galaxies with higher radio luminosities is more efficient in heating the cosmic-ray electrons.

Keywords

Keywords galaxies: active - galaxies: Seyfert - galaxies: starburst - radio continuum: galaxies - infrared: galaxies

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