A Deep Chandra Observation of the X-shaped Radio Galaxy 4C +00.58: A Candidate for Merger-induced Reorientation?

TL;DR

This study uses deep Chandra X-ray observations of the X-shaped radio galaxy 4C +00.58 to investigate wing formation mechanisms, providing evidence that supports a merger-induced reorientation over hydrodynamic models.

Contribution

The paper presents the first detailed X-ray analysis of 4C +00.58, offering evidence for merger-induced reorientation as the origin of its X-shaped structure.

Findings

Presence of X-ray cavities indicating past jet activity along a different axis.

Detection of a stellar shell suggesting a recent galaxy merger.

Hydrodynamic models struggle to explain the long wings observed.

Abstract

Although rapid reorientation of a black hole spin axis (lasting less than a few Myr) has been suggested as a mechanism for the formation of wings in X-shaped radio galaxies (XRGs), to date no convincing case of reorientation has been found in any XRG. Alternative wing formation models such as the hydrodynamic backflow models are supported by observed trends indicating that XRGs form preferentially with jets aligned along the major axis of the surrounding medium and wings along the minor axis. In this Letter, we present a deep Chandra observation of 4C +00.58, an oddball XRG with its jet oriented along the minor axis. By using the X-ray data in tandem with available radio and optical data, we estimate relevant timescales with which to evaluate wing formation models. The hydrodynamic models have difficulty explaining the long wings, whereas the presence of X-ray cavities (suggesting jet activity along a prior axis) and a potential stellar shell (indicating a recent merger) favor a merger-induced reorientation model.