Free access article

A&A 369, 441-449 (2001)
DOI: 10.1051/0004-6361:20010115

A comparison of radio and X-ray morphologies of four clusters of galaxies containing radio halos

F. Govoni^{1, 2}, T. A. Enßlin³, L. Feretti¹ and G. Giovannini<sup>1, 4

1</sup>  Istituto di Radioastronomia del CNR, Via P. Gobetti 101, 40129 Bologna, Italy
²  Dipartimento di Astronomia, Univ. di Bologna, via Ranzani 1, 40127 Bologna, Italy
³  Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str.1, 85740 Garching, Germany
⁴  Dipartimento di Fisica, Univ. di Bologna, via Berti-Pichat 6/2, 40127 Bologna, Italy

(Received 10 August 2000 / Accepted 12 January 2001 )

Abstract
Clusters of galaxies may contain cluster-wide, centrally located, diffuse radio sources, called halos. They have been found to show morphologies similar to those of the X-ray emission. To quantify this qualitative statement we performed a point-to-point comparison of the radio and the X-ray emission for four clusters of galaxies containing radio halos: Coma, Abell 2255, Abell 2319, Abell 2744. Our study leads to a linear relation between the radio and the X-ray surface brightness in two clusters, namely Abell 2255 and Abell 2744. In Coma and A2319 the radio and the X-ray brightnesses seem to be related with a sub-linear power law. Implications of these findings within simple radio halo formation models are briefly discussed.

Key words: radiation mechanism: non-thermal -- radio continuum: general -- galaxies: clusters: general -- galaxies: intergalactic medium -- magnetic fields

Offprint request: F. Govoni, fgovoni@astbo1.bo.cnr.it

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© ESO 2001

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