Radio-Optical Alignment of Radio Galaxies

TL;DR

This study analyzes the alignment between radio jets and optical axes in over 2000 radio galaxies, confirming a common tendency for jets to be ejected near the optical minor axis, with detailed measurements from radio and optical data.

Contribution

It provides a large-scale analysis of radio-optical alignment in radio galaxies, confirming the predominant minor-axis ejection and examining correlations with galaxy size and morphology.

Findings

Majority of radio galaxies have jets within 30° of optical minor axis

No stronger alignment observed in larger radio sources

No evidence of a population with radio axes parallel to optical major axes

Abstract

Images from recent radio surveys were used to determine the radio position angles for over 2000 extended radio galaxies with host galaxies brighter than m$_{r}\sim$18 mag. For 1509 of these their optical axis ratios were obtained, and for a subset of 857 also their major axis position angle. It is confirmed that the majority of radio galaxies have their jets or lobes ejected within $\sim30^{\circ}$ of the optical minor axis of their host, but no evidence is found for the minor-axis alignment to be stronger for physically larger radio sources, nor for the presence of a secondary population of brightest cluster galaxies with radio axes near to parallel to their optical major axes.