EDP Sciences
Free Access
Volume 486, Number 3, August II 2008
Page(s) L31 - L34
Section Letters
DOI https://doi.org/10.1051/0004-6361:200810179
Published online 16 June 2008

A&A 486, L31-L34 (2008)
DOI: 10.1051/0004-6361:200810179


A morphological comparison between giant radio halos and radio mini-halos in galaxy clusters

R. Cassano1, M. Gitti2, and G. Brunetti1

1  INAF - Istituto di Radioastronomia, via P. Gobetti 101, 40129 Bologna, Italy
    e-mail: rcassano@ira.inaf.it
2  INAF - Osservatorio Astronomico di Bologna, via Ranzani 1, 40127 Bologna, Italy

Received 12 May 2008 / Accepted 9 June 2008

In this letter we present a morphological comparison between giant radio halos and radio mini-halos in galaxy clusters based on radio-X-ray luminosity, P1.4-$L_{\rm X}$, and radio luminosity-size, P1.4-$R_{\rm H}$, correlations. We report evidence that P1.4-$L_{\rm X}$ and P1.4-$R_{\rm H}$ trends may also exist for mini-halos: mini-halo clusters share the same region of giant halo clusters in the $(P_{1.4},L_{\rm X})$ plane, whereas they are clearly separated in the $(P_{1.4},R_{\rm H})$ plane. The synchrotron emissivity of mini-halos is found to be more than 50 times larger than that of giant halos, implying a very efficient process for their origins. By assuming a scenario of sporadical turbulent particle re-acceleration for both giant and mini halos, we discuss basic physical differences between these sources. Regardless of the origin of the turbulence, a more efficient source of injection of particles, which eventually takes part in the re-acceleration process, is required in mini-halos, and this may result from the central radio galaxy or from proton-proton collisions in the dense cool core regions.

Key words: radiation mechanism: non-thermal -- galaxies: clusters: general -- radio continuum: general -- X-rays: general

© ESO 2008

Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.

Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.

Initial download of the metrics may take a while.