Study of some morphological features of extragalactic radio sources of FRI and FRII types

Abstract

It was used the date of more than 650 extragalactic radio sources for the study of distribution of spectral indexes and elongation for the radio sources of different Fanaroff Riley (FR) classes. It was shown, that no large differences are observed in the distribution of spectral indexes in radio sources FRI and FRII classes. From the study of distribution of the elongation of extragalactic radio sources it was found the following basic morphological differences for the objects of different FR classes: a) the radio images of extragalactic radio sources FRII type in the average are more elongated than the radio images of extragalactic radio sources FRI type: b) the extragalactic radio sources FRI type can be divided on two subtypes with two function of distribution of the elongation parameter K having different maximums. These two subtypes of radio sources of FRI class, in besides of different average elongation of radio images, probably must have also differences in the orientations of these elongation directions relative to the direction of rotation axes of parent optical galaxies that in most cases are coincide with the minor optical axes of galaxies.