Effective radii and color gradients in radio galaxies

We present de Vaucouleurs's effective radii in B and R bands for a sample o f Molonglo Reference Catalogue radio galaxies and a control sample of norma l galaxies. We use the ratio of the scale lengths in the two bands as an in dicator 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 gala xies do. We show that the scale length ratio is a useful indicator of radia l color variation, even when the conventional color gradient is too noisy t o serve the purpose.