The rotation axes of 3C 33, 3C 98, 3C 184.1, and 3C 218

Abstract

An analysis based on digital spectroscopy of 3C 33, 98, 184.1, and 218 is presented, which has the objective of discovering whether there is any correlation between the radio and rotation axes of radio galaxies. An attempt was made to derive a rotation axis for the stellar as well as gaseous component of each galaxy. The emission-line measurements reveal two previously unrecognized characteristics of optical galaxies associated with double radio sources: they have relatively high internal rotation velocities, and their rotation axes are nearly aligned with their radio axes. The slight misalignment found between the two axes for every object measured, however, appears to be significant and to support the hypothesis that the radio plasma in such galaxies is ejected along an axis which is precessing.