A radio continuum survey of Shapley-Ames galaxies at 2.8 cm
III. The radio - far infrared correlation
Received 28 May 1996 / Accepted 22 July 1996
Radio flux densities of Shapley-Ames galaxies at 2.8 cm from Niklas et al. (1995a, Paper I) and at 20 cm from Condon (1987, C87) have been used to investigate the radio - far infrared (FIR) correlation at two different radio wavelengths. The correlation between monochromatic radio and the FIR luminosity was found to be non-linear ( and ). Galaxies with Seyfert activity often exhibit enhanced radio emission compared to the FIR. Interacting and Starburst Galaxies do not show significant deviations from the correlation. For 74 galaxies with separated thermal and non-thermal radio emission the thermal radio luminosity was found to be proportional to the FIR luminosity. At both frequencies the non-thermal radio luminosity is non-linearly connected to the FIR luminosity (). From the ratio one can conclude that 30 % of the FIR emission can be attributed to dust associated with massive star-forming regions.
Key words: galaxies: spiral infrared: galaxies radio continuum: galaxies ISM: cosmic rays
Send offprint requests to: S.Niklas
© European Southern Observatory (ESO) 1997
Online publication: June 30, 1998