2016/07/31 by K. G. Biju, J. Bagchi, Joydeep Bagchi +17 · 8 citations
Physics and Astronomy · #Active galactic nucleus #Astronomy #Astrophysics #Astrophysics and Cosmic Phenomena #Black hole (networking) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Physics #Radio Astronomy Observations and Technology #Radio galaxy #Spectral index #Spectral line #X-shaped radio galaxy #astro-ph.CO #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stx1476
published in Monthly Notices of the Royal Astronomical Society 471(1), 617-628 (Oxford University Press) · Published in MNRAS | No. of pages 12, 10 figures and 4 tables. Comments are welcome
openalex publication_date 2017/06/14 · arxiv created 2017/08/16 · arxiv updated 2017/08/17 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
We report the results of our radio, optical and infrared studies of a peculiar radio source 4C 35.06, an extended radio-loud active galactic nucleus (AGN) at the centre of galaxy cluster Abell 407 (z = 0.047). The central region of this cluster hosts a remarkably tight ensemble of nine galaxies, the spectra of which resemble those of passive red ellipticals, embedded within a diffuse stellar halo of ∼1 arcmin size. This system (named ‘Zwicky's Nonet’) provides unique and compelling evidence for a multiple-nucleus cD galaxy precursor. Multifrequency radio observations of 4C 35.06 with the Giant Meterwave Radio Telescope (GMRT) at 610, 235 and 150 MHz reveal a system of 400-kpc scale helically twisted and kinked radio jets and outer diffuse lobes. The outer extremities of jets contain extremely steep-spectrum (spectral index −1.7 to −2.5) relic/fossil radio plasma with a spectral age of a few ×(107–108) yr. Such ultra-steep spectrum relic radio lobes without definitive hotspots are rare and they provide an opportunity to understand the life cycle of relativistic jets and physics of black hole mergers in dense environments. We interpret our observations of this radio source in the context of growth of its central black hole, triggering of its AGN activity and jet precession, all possibly caused by galaxy mergers in this dense galactic system. A slow conical precession of the jet axis due to gravitational perturbation between interacting black holes is invoked to explain the unusual jet morphology.