X-shaped radio galaxy 3C 223.1: A 'double boomerang' with an anomalous spectral gradient

Abstract

A comparison of the recent LOFAR 144 MHz map of the radio source 3C 223.1 (J094124.028+394441.95) with the VLA maps at 4.9 GHz and 8.3 GHz that we built based on archival data, establishes this X-shaped radio galaxy (XRG) as a singularly robust case where the 'wings' exhibit a distinctly flatter radio spectrum than the primary lobes. The details of its anomalous spectral gradient are unravelled here with unprecedented precision. We also highlight the 'double boomerang' type radio morphology of this XRG. It appears plausible that the peculiar spectral gradient in this XRG is owed to particle acceleration associated with the rebounding of the collimated backflows of synchrotron plasma streaming through its two primary lobes, as they impinge upon and encounter the magnetic tension in the prominent dusty disk of the elliptical galaxy hosting this XRG. We also draw attention to an intriguing new morphological peculiarity among XRGs, namely, a lateral offset observed between the (parallel) axes of the two primary radio lobes.

Accepted for publication in A&A Letters |3 figures and 2 tables | Comments are welcome

References in corpus (10)

• The LOFAR Two-metre Sky Survey -- V. Second data release
• Deep LOFAR observations of the merging galaxy cluster CIZA J2242.8+5301
• Hydrodynamical Backflow in X-shaped Radio Galaxy PKS 2014-55
• Jets from MRC 0600-399 bent by magnetic fields in the cluster Abell 3376
• X-shaped Radio Galaxies: Optical Properties, Large-scale Environment and Relationship to Radio Structure
• Modelling X-shaped Radio Galaxies: Dynamical and Emission Signatures from the Back-flow model
• GMRT Low-frequency Imaging of an Extended Sample of X-shaped Radio Galaxies
• Cold gas and dust: Hunting spiral-like structures in early-type galaxies
• Superdisks and the structural asymmetry of radio galaxies
• Discovery of X-shaped Morphology of the Giant Radio Galaxy GRG 0503-286