Issue |
A&A
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 |
Letter to the Editor
A morphological comparison between giant radio halos and radio mini-halos in galaxy clusters
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-LX, and
radio luminosity-size, P1.4-RH, correlations.
We report evidence that P1.4-LX and
P1.4-RH trends may also exist for mini-halos:
mini-halo clusters share the same region of giant halo clusters in the plane, whereas they are clearly separated in the
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
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