TY - JOUR
T1 - Observations of extended radio emission in clusters
AU - Ferrari, C.
AU - Govoni, F.
AU - Schindler, S.
AU - Bykov, A. M.
AU - Rephaeli, Y.
N1 - Funding Information:
Acknowledgements The authors thank ISSI (Bern) for support of the team “Non-virialized X-ray components in clusters of galaxies”. CF and FG warmly thank Luigina Feretti and Matteo Murgia for many useful discussions on the subject of this paper. CF and SS acknowledge financial support by the Austrian Science Foundation (FWF) through grants P18523-N16 and P19300-N16, by the Tiroler Wissenschaftsfonds and through the UniInfrastrukturprogramm 2005/06 by the BMWF. FG acknowledges financial support through Grant ASI-INAF I/088/06/0—High Energy Astrophysics.
PY - 2008/2
Y1 - 2008/2
N2 - We review observations of extended regions of radio emission in clusters; these include diffuse emission in 'relics', and the large central regions commonly referred to as 'halos'. The spectral observations, as well as Faraday rotation measurements of background and cluster radio sources, provide the main evidence for large-scale intracluster magnetic fields and significant densities of relativistic electrons. Implications from these observations on acceleration mechanisms of these electrons are reviewed, including turbulent and shock acceleration, and also the origin of some of the electrons in collisions of relativistic protons by ambient protons in the (thermal) gas. Improved knowledge of non-thermal phenomena in clusters requires more extensive and detailed radio measurements; we briefly review prospects for future observations.
AB - We review observations of extended regions of radio emission in clusters; these include diffuse emission in 'relics', and the large central regions commonly referred to as 'halos'. The spectral observations, as well as Faraday rotation measurements of background and cluster radio sources, provide the main evidence for large-scale intracluster magnetic fields and significant densities of relativistic electrons. Implications from these observations on acceleration mechanisms of these electrons are reviewed, including turbulent and shock acceleration, and also the origin of some of the electrons in collisions of relativistic protons by ambient protons in the (thermal) gas. Improved knowledge of non-thermal phenomena in clusters requires more extensive and detailed radio measurements; we briefly review prospects for future observations.
KW - Acceleration of particles
KW - Galaxies: clusters: general
KW - Galaxies: intergalactic medium
KW - Magnetic fields
KW - Radiation mechanisms: non-thermal
KW - Radio continuum: general
UR - http://www.scopus.com/inward/record.url?scp=43349084270&partnerID=8YFLogxK
U2 - 10.1007/s11214-008-9311-x
DO - 10.1007/s11214-008-9311-x
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AN - SCOPUS:43349084270
SN - 0038-6308
VL - 134
SP - 93
EP - 118
JO - Space Science Reviews
JF - Space Science Reviews
IS - 1-4
ER -