Result: A low-frequency radio halo associated with a cluster of galaxies

Title:
A low-frequency radio halo associated with a cluster of galaxies
Authors:
BRUNETTI, G, GIACINTUCCI, S, CASSANO, R, LANE, W, DALLACASA, D, VENTURI, T, KASSIM, N. E, SETTI, G, COTTON, W. D, MARKEVITCH, M
Source:
Nature (London). 455(7215):944-947
Publisher Information:
London: Nature Publishing Group, 2008.
Publication Year:
2008
Physical Description:
print, 30 ref
Original Material:
INIST-CNRS
Subject Terms:
Multidisciplinary, Multidisciplinaire, Sciences exactes et technologie, Exact sciences and technology, Terre, ocean, espace, Earth, ocean, space, Astronomie, Astronomy, Systèmes stellaires. Objets et systèmes galactiques et extragalactiques. L'univers, Stellar systems. Galactic and extragalactic objects and systems. The universe, Groupes, amas et superamas de galaxies. Structure à grande échelle de l'univers, Galaxy groups, clusters, and superclusters. Large-scale structure of the universe, Amas de galaxies, Galaxy clusters, Amas galaxies, Galaxy clusters, Champ magnétique, Magnetic fields, Collision particule, Particle collision, Colisión partícula, Electron relativiste, Relativistic electron, Electrón relativista, Fréquence coupure, Cut off frequency, Frecuencia corte, Gaz chaud, Hot gas, Gas caliente, Halo radio, Radio halo, Matière sombre, Dark matter, Particule relativiste, Relativistic particle, Partícula relativista, Particule secondaire, Secondary particle, Partícula secundaria, Proton, Protons, Rayonnement synchrotron, Synchrotron radiation, Spectre radio, Radio spectrum, Espectro radio, Turbulence
Document Type:
Academic journal Article
File Description:
text
Language:
English
Author Affiliations:
NAF -Istituto di Radioastronomia, Via P. Gobetti 101, 40129 Bologna, Italy
Harvard-Smithsonian Center for Astrophysics, Cambridge, Massachusetts 02138, United States
Naval Research Laboratory, Code 7213, Washington DC 20375-5320, United States
Dipartimento di Astronomia, Università di Bologna, Via Ranzani 1, 40127 Bologna, Italy
National Radio Astronomy Observatory, Charlottesville, Virginia 22903-2475, United States
ISSN:
0028-0836
Access URL:
http://pascal-francis.inist.fr/vibad/index.php?action=search&terms=20737843
Rights:
Copyright 2009 INIST-CNRS
CC BY 4.0
Sauf mention contraire ci-dessus, le contenu de cette notice bibliographique peut être utilisé dans le cadre d’une licence CC BY 4.0 Inist-CNRS / Unless otherwise stated above, the content of this bibliographic record may be used under a CC BY 4.0 licence by Inist-CNRS / A menos que se haya señalado antes, el contenido de este registro bibliográfico puede ser utilizado al amparo de una licencia CC BY 4.0 Inist-CNRS
Notes:
Astronomy
Accession Number:
edscal.20737843
Database:
PASCAL Archive

Further Information

Clusters of galaxies are the largest gravitationally bound objects in the Universe, containing about 1015 solar masses of hot (108 K) gas, galaxies and dark matter in a typical volume of 10 Mpc3. Magnetic fields and relativistic particles are mixed with the gas as revealed by giant 'radio haloes', which arise from diffuse, megaparsec-scale synchrotron radiation at cluster centre1,2. Radio haloes require that the emitting electrons are accelerated in situ (by turbulence)3-6, or are injected (as secondary particles) by proton collisions into the intergalactic medium7-10. They are found only in a fraction of massive clusters that have complex dynamics11-14, which suggests a connection between these mechanisms and cluster mergers. Here we report a radio halo at low frequencies associated with the merging cluster Abell 521. This halo has an extremely steep radio spectrum, which implies a high frequency cut-off; this makes the halo difficult to detect with observations at 1.4 GHz (the frequency at which all other known radio haloes have been best studied). The spectrum of the halo is inconsistent with a secondary origin of the relativistic electrons, but instead supports turbulent acceleration, which suggests that many radio haloes in the Universe should emit mainly at low frequencies.