From 100 MHz to 10 GHz: Unveiling the spectral evolution of the X-shaped radio galaxy in Abell 3670

Abstract

X-shaped radio galaxies (XRGs) are characterised by two pairs of misaligned lobes, namely the active lobes hosting radio jets and the wings. None of the formation mechanisms proposed so far can exhaustively reproduce the diverse features observed among XRGs. The emerging evidence is the existence of sub-populations of XRGs forming via different processes. The brightest cluster galaxy in Abell 3670 (A3670) is a dumbbell system hosting the XRG MRC 2011-298. The morphological and spectral properties of this interesting XRG have been first characterised through Karl G. Jansky Very Large Array (JVLA) data at 1-10 GHz. In the present work, we followed-up MRC 2011-298 with the upgraded Giant Metrewave Radio Telescope (uGMRT) at 120-800 MHz to further constrain its properties and origin. We carried out a detailed spectral analysis sampling different spatial scales. Integrated radio spectra, spectral index maps, radio colour-colour diagrams, and radiative age maps of both the active lobes and prominent wings have been employed to test the origin of the source. We confirm a progressive spectral steepening from the lobes to the wings. The maximum radiative age of the source is $\sim 80$ Myr, with the wings being older than the lobes by $\gtrsim 30$ Myr in their outermost regions. The observed properties are in line with an abrupt reorientation of the jets by $\sim 90$ deg from the direction of the wings to their present position. This formation mechanism is further supported by the comparison with numerical simulations in the literature, which additionally highlight the role of hydrodynamic processes in the evolution of large wings such as those of MRC 2011-298. Potentially, the coalescence of supermassive black holes could have triggered the spin-flip of the jets. Moreover, we show that the S-shape of the radio jets is likely driven by precession with a period $P\sim 10$ Myr.

arXiv comment23 pages (including Appendices), 14 figures. Accepted for publication in A&A

References in corpus (46)

• SciPy 1.0--Fundamental Algorithms for Scientific Computing in Python
• Astropy: A Community Python Package for Astronomy
• The 6dF Galaxy Survey: Final Redshift Release (DR3) and Southern Large-Scale Structures
• WSClean: an implementation of a fast, generic wide-field imager for radio astronomy
• The Pan-STARRS1 Database and Data Products
• Ionospheric Calibration of Low Frequency Radio Interferometric Observations using the Peeling Scheme: I. Method Description and First Results
• An optimized algorithm for multi-scale wideband deconvolution of radio astronomical images
• Tracing Black Hole Mergers Through Radio Lobe Morphology
• The first XMM-Newton slew survey catalogue: XMMSL1
• The Rapid ASKAP Continuum Survey I: Design and First Results
• Spectral ageing in the lobes of FR-II radio galaxies: New methods of analysis for broadband radio data
• Jet reorientation in AGN: two winged radio galaxies
• The late time radio emission from SN 1993J at meter wavelengths
• On the origin of X-shaped radio-sources: new insights from the properties of their host galaxies
• The dynamical state of brightest cluster galaxies and the formation of clusters
• A Chandra Study of the Multi-Component X-ray Emission from the X-shaped Radio Galaxy 3C 403
• X-shaped radio galaxies as observational evidence for the interaction of supermassive binary black holes and accretion disk at pc scale
• The Origin of X-shaped Radio Galaxies: Clues from the Z-symmetric Secondary Lobes
• X-ray scaling relations for a representative sample of Planck selected clusters observed with XMM-Newton
• The spin-flip phenomenon in supermassive black hole binary mergers
• Scaling Properties of Galaxy Groups
• Spectral ageing in the lobes of cluster-centre FR-II radio galaxies
• Hydrodynamical Backflow in X-shaped Radio Galaxy PKS 2014-55
• The genesis of morphologies in extended radio sources: X-shapes, off-axis distortions and giant radio sources
• How frequent are close supermassive binary black holes in powerful jet sources?
• A spinning supermassive black hole binary model consistent with VLBI observations of the S5 1928+738 jet
• Two New Catalogues of Superclusters of Abell/ACO Galaxy Clusters out to redshift 0.15
• The Rapid ASKAP Continuum Survey IV: continuum imaging at 1367.5 MHz and the first data release of RACS-mid
• NGC 326: X-shaped no more
• Synchrotron and inverse-Compton emission from radio galaxies with non-uniform magnetic field and electron distributions
• The radio structures of southern 2-Jy radio sources: new ATCA and VLA radio images
• Hydrodynamic Models of Radio Galaxy Morphology: Winged and X-shaped Sources
• Catching butterflies in the sky: Extended catalog of winged or X-shaped radio sources from the latest FIRST data release
• FIRST "Winged" and X-shaped Radio Source Candidates: II. New Redshifts
• The optical spectra of X-shaped radio galaxies
• Multiwavelength study of Cygnus A I. Precession and slow jet speeds from radio observations
• A Deep Chandra Observation of the X-shaped Radio Galaxy 4C +00.58: A Candidate for Merger-induced Reorientation?
• Narrow head-tail radio galaxies at very high resolution
• FIRST winged radio galaxies with X and Z symmetry
• The twisted jets of Circinus X-1
• Modelling X-shaped Radio Galaxies: Dynamical and Emission Signatures from the Back-flow model
• Starbursts and black hole masses in X-shaped radio galaxies: Signatures of a merger event?
• Dynamical Modelling and Emission Signatures of a Candidate Dual AGN with Precessing Radio Jets
• Simulations of Precessing Jets and the Formation of X-shaped Radio Galaxies
• Hard X-ray selected giant radio galaxies -- III. The LOFAR view
• Multifrequency JVLA observations of the X-shaped radio galaxy in Abell 3670

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