Signatures from a merging galaxy cluster and its AGN population: LOFAR observations of Abell 1682

Abstract

We present LOFAR data from 110--180~MHz of the merging galaxy cluster Abell 1682, alongside archival optical, radio and X-ray data. Our 6 arc-second resolution images at low frequencies reveal new structures associated with numerous radio galaxies in the cluster. At 20 arc-second resolution we see diffuse emission throughout the cluster over hundreds of kpc, indicating particle acceleration mechanisms are in play as a result of the cluster merger event and powerful active galactic nuclei. We show that a significant part of the cluster emission is from an old radio galaxy with very steep spectrum emission (having a spectral index of $\alpha <-2.5$). Furthermore we identify a new region of diffuse steep spectrum emission ($\alpha <-1.1$) as a candidate for a radio halo which is co-spatial with the centre of the cluster merger. We suggest its origin as a population of old and mildly relativistic electrons left over from radio galaxies throughout the cluster which have been re-accelerated to higher energies by shocks and turbulence induced by the cluster merger event. We also note the discovery of six new giant radio galaxies in the vicinity of Abell 1682.

Accepted in A&A; see journal version for uncompressed figures

References in corpus (16)

• Diffuse Radio Emission from Galaxy Clusters
• Compressible Turbulence in Galaxy Clusters: Physics and Stochastic Particle Re-acceleration
• The Very Large Array Low-frequency Sky Survey Redux (VLSSr)
• A low-frequency radio halo associated with a cluster of galaxies
• GMRT Radio Halo Survey in galaxy clusters at z = 0.2 -- 0.4. II.The eBCS clusters and analysis of the complete sample
• Radio interferometric gain calibration as a complex optimization problem
• The Case for Electron Re-Acceleration at Galaxy Cluster Shocks
• Statistics of Giant Radio Halos from Electron Reacceleration Models
• Non-Thermal Electron Acceleration in Low Mach Number Collisionless Shocks. I. Particle Energy Spectra and Acceleration Mechanism
• Non-Thermal Electron Acceleration in Low Mach Number Collisionless Shocks. II. Firehose-Mediated Fermi Acceleration and its Dependence on Pre-Shock Conditions
• Turbulence and Particle Acceleration in Giant Radio Haloes: the Origin of Seed Electrons
• Gentle re-energisation of electrons in merging galaxy clusters
• Search and modelling of remnant radio galaxies in the LOFAR Lockman Hole field
• LOFAR discovery of an ultra-steep radio halo and giant head-tail radio galaxy in Abell 1132
• Deep LOFAR observations of the merging galaxy cluster CIZA J2242.8+5301
• Spectral age modelling of the `Sausage' cluster radio relic

Cited by in corpus (9)

• LOFAR observations of galaxy clusters in HETDEX
• The Planck clusters in the LOFAR sky. I. LoTSS-DR2: new detections and sample overview
• Radio footprints of a minor merger in the Shapley Supercluster: From supercluster down to galactic scales
• A MeerKAT-meets-LOFAR Study of MS 1455.0+2232: A 590 kiloparsec 'Mini'-Halo in a Sloshing Cool-Core Cluster
• A candle in the wind: a radio filament in the core of the A3562 galaxy cluster
• Shocked Narrow-Angle Tail Radio Galaxies: Simulations and Emissions
• Gas sloshing and cold fronts in pre-merging galaxy cluster Abell 98
• The structure of the giant radio fossil in the Ophiuchus galaxy cluster
• The contribution of non-central radio galaxies to AGN feedback in rich galaxy clusters