FIRST "Winged" and X-shaped Radio Source Candidates: II. New Redshifts

TL;DR

This study presents new spectroscopic redshifts for X-shaped radio source candidates, revealing two new broad-lined sources and analyzing their properties relative to the Fanaroff-Riley classification.

Contribution

It provides the first substantial spectroscopic confirmation of X-shaped radio source candidates and explores their physical properties and classification in the Owen-Ledlow plane.

Findings

Over 50% of candidates spectroscopically identified

Discovered two new broad emission-lined X-shaped sources

Analyzed radio luminosities and host magnitudes in the Owen-Ledlow plane

Abstract

We report optical spectroscopic observations of X-shaped radio sources with the Hobby-Eberly Telescope and Multiple-Mirror Telescope, focused on the sample of candidates from the FIRST survey presented in Paper I (Cheung 2007). A total of 27 redshifts were successfully obtained, 21 of which are new, including that of a newly identified candidate source of this type which is presented here. With these observations, the sample of candidates from Paper I is over 50% spectroscopically identified. Two new broad emission-lined X-shaped radio sources are revealed, while no emission lines were detected in about one third of the observed sources; a detailed study of the line properties is deferred to a future paper. Finally, to explore their relation to the Fanaroff-Riley division, the radio luminosities and host galaxy absolute magnitudes of a spectroscopically identified sample of 50 X-shaped radio galaxies are calculated to determine their placement in the Owen-Ledlow plane.