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Title: Evidence for particle re-acceleration in the radio relic in the galaxy cluster PLCKG287.0+32.9

Radio relics are diffuse radio sources observed in galaxy clusters, probably produced by shock acceleration during cluster-cluster mergers. Their large size, of the order of 1 Mpc, indicates that the emitting electrons need to be (re)accelerated locally. The usually invoked diffusive shock acceleration models have been challenged by recent observations and theory. We report the discovery of complex radio emission in the Galaxy cluster PLCKG287.0+32.9, which hosts two relics, a radio halo, and several radio filamentary emission. Optical observations suggest that the cluster is elongated, likely along an intergalactic filament, and displays a significant amount of substructure. The peculiar features of this radio relic are that (1) it appears to be connected to the lobes of a radio galaxy and (2) the radio spectrum steepens on either side of the radio relic. We discuss the origins of these features in the context of particle re-acceleration.
Authors:
;  [1] ;  [2] ;  [3] ;  [4] ;  [5] ;  [6] ;  [7]
  1. Hamburger Sternwarte, Universität Hamburg, Gojenbergsweg 112, D-21029 Hamburg (Germany)
  2. National Radio Astronomy Observatory, 1003 Lopezville Road, Socorro, NM 87801-0387 (United States)
  3. Dipartimento di Fisica-Sezione di Astronomia, Universitá di Trieste, via Tiepolo 11, I-34143 Trieste (Italy)
  4. INAF—Osservatorio Astronomico di Trieste, via Tiepolo 11, I-34143 Trieste (Italy)
  5. National center for Radio Astrophysics, TIFR, Post Bag 3, Ganeshkhind, Pune 411 007 (India)
  6. Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)
  7. Leiden Observatory, Leiden University, 2300 RA Leiden (Netherlands)
Publication Date:
OSTI Identifier:
22357207
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 785; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ACCELERATION; ELECTRONS; EMISSION; FILAMENTS; GALAXY CLUSTERS; MAGNETIC FIELDS; RADIO GALAXIES; SHOCK WAVES; SPECTRA