A discovery of young radio sources in the cores of giant radio galaxies selected at hard X-rays

Abstract

Giant Radio Galaxies (GRG) are the largest single entities in the Universe, having a projected linear size exceeding 0.7 Mpc, which implies that they are also quite old objects. They are not common, representing a fraction of only about 6% in samples of bright radio galaxies. While a census of about 300 of these objects has been built in the past years, still no light has been shed on the conditions necessary to allow such an exceptional growth, whether of environmental nature or linked to the inner accretion properties. Recent studies found that samples of radio galaxies selected from hard X-ray AGN catalogs selected from INTEGRAL/IBIS and Swift/BAT (thus at energies >20 keV) present a fraction of GRG four times larger than what found in radio-selected samples. We present radio observations of 15 nuclei of hard X-ray selected GRG, finding for the first time a large fraction (61%) of young radio sources at the center of Mpc-scale structures. Being at the center of GRG, these young nuclei may be undergoing a restarting activity episode, suggesting a link between the detected hard X-ray emission - due to the ongoing accretion - and the reactivation of the jets.

arXiv commentAccepted for publication on ApJ

References in corpus (27)

• Binary companions of evolved stars in APOGEE DR14: Search method and catalog of ~5,000 companions
• The GMRT 150 MHz All-sky Radio Survey: First Alternative Data Release TGSS ADR1
• SUMSS: A Wide-Field Radio Imaging Survey of the Southern Sky. II. The Source Catalogue
• GaLactic and Extragalactic All-sky Murchison Widefield Array (GLEAM) survey I: A low-frequency extragalactic catalogue
• CRATES: An All-Sky Survey of Flat-Spectrum Radio Sources
• An Accurate Flux Density Scale from 50 MHz to 50 GHz
• Extragalactic Peaked-Spectrum Radio Sources at Low Frequencies
• Giant Radio Sources
• The local radio-galaxy population at 20 GHz
• A multifrequency study of giant radio sources-II. Spectral ageing analysis of the lobes of selected sources
• An updated catalogue of giant radio sources
• VLBA images of High Frequency Peakers
• ATPMN: accurate positions and flux densities at 5 and 8 GHz for 8,385 sources from the PMN survey
• Radio observations of a few giant sources
• The NOD3 software package: A graphical user interface-supported reduction package for single-dish radio continuum and polarisation observations
• Radio spectra and polarisation properties of a bright sample of Radio-Loud Broad Absorption Line Quasars
• Soft Gamma-ray selected radio galaxies: favouring giant size discovery
• Restarting activity in the nucleus of PBC J2333.9-2343: an extreme case of jet realignment
• The INTEGRAL/IBIS AGN catalogue: an update
• High Frequency Peakers
• Hard X-ray selected giant radio galaxies - I. The X-ray properties and radio connection
• B0707-359: a case study of change in AGN-black hole spin axis
• The asymmetric radio structure and record jet of giant quasar 4C34.47
• IGR J17488-2338: a newly discovered giant radio galaxy
• Broadband X-ray spectrum of the newly discovered broad line radio galaxy IGR J21247+5058
• Variable broad lines and outflow in the weak blazar PBC J2333.9-2343
• A multi-wavelength continuum characterization of high-redshift broad absorption line quasars

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• Compact steep-spectrum and peaked-spectrum radio sources
• Search and analysis of giant radio galaxies with associated nuclei (SAGAN) -- I : New sample and multi-wavelength studies
• The duty cycle of radio galaxies revealed by LOFAR: remnant and restarted radio source populations in the Lockman Hole
• The life cycle of radio galaxies in the LOFAR Lockman Hole field
• Hard X-ray selected giant radio galaxies -- II. Morphological evidence of restarted radio activity
• INTEGRAL view of AGN
• On the diversity of the jet production efficiency in Swift/BAT AGNs
• SAGAN-II : Molecular gas content of giant radio galaxies
• Hard X-ray selected giant radio galaxies -- III. The LOFAR view
• A new look at old friends. I. Imaging classical radio galaxies with uGMRT and MeerKAT
• The morphological classification of distant radio galaxies explored with three-dimensional simulations
• Soft gamma-ray selected giant radio galaxies: an update
• Hard - X-rays selected Active Galactic Nuclei. I. A radio view at high-frequencies
• Powerful Radio Sources in the Southern Sky. I. Optical Identifications
• Robust Supermassive Black Hole Spin Mass-Energy Characteristics: A New Method and Results
• Core prominence as a signature of restarted jet activity in the LOFAR radio-galaxy population
• Probing restarting activity in hard X-ray selected giant radio galaxies
• HST WFC3/Grism Observations of the Candidate Ultra-High-Redshift Radio Galaxy GLEAM J0917-0012
• Bridging Bondi and Event Horizon Scales: 3D GRMHD Simulations Reveal X-Shaped Radio Galaxy Morphology