Effective radii and color gradients in radio galaxies

Abstract

We present de Vaucouleurs's effective radii in B and R bands for a sample of Molonglo Reference Catalogue radio galaxies and a control sample of normal galaxies. We use the ratio of the scale lengths in the two bands as an indicator in order to show that the radio galaxies tend to have an excess of blue color in their inner region much more frequently than the control galaxies do. We show that the scale length ratio is a useful indicator of radial color variation, even when the conventional color gradient is too noisy to serve the purpose.