Constraining B in galaxy clusters from statistics of giant radio halos

Abstract

There are several possibilities to constrain the value of the magnetic field in the ICM, the most direct ones being the combination of inverse Compton and synchrotron observations, and the Faraday rotation measures. Here we discuss on the possibility to provide constraints on the magnetic field in the ICM from the analysis of the statistical properties of the giant radio halos, Mpc--scale diffuse radio emission in galaxy clusters. Present observations of a few well studied radio halos can be interpreted under the hypothesis that the emitting relativistic electrons are re-accelerated on their way out. By using statistical calculations carried out in the framework of the re-acceleration model we show that the observed radio--power vs cluster mass correlation in radio halos can be reproduced only by assuming $\mu$G fields in the ICM and a scaling of the magnetic field with cluster mass $B\propto M_v^b$, with $b\ge 0.6$. We also show that the expected occurrence of radio halos with mass and redshift, and their number counts are sensitive to the magnetic field intensity in massive galaxy clusters and to the scaling of B with cluster mass. Thus future deep surveys of radio halos would provide constraints on B in galaxy clusters.

arXiv comment4 pages, 4 figures. To appear in the Proceedings of the International Conference: "The Origin and Evolution of Cosmic Magnetism"; Bologna 29 August - 2 September 2005; eds R. Beck, G. Brunetti, L. Feretti, and B. Gaensler (Astronomische Nachrichten, 2006)

References in corpus (14)

• The statistics of LCDM Halo Concentrations
• Particle reacceleration in Coma cluster: radio properties and hard X-ray emission
• Magnetic Field in Clusters of Galaxies
• On The Non Thermal Emission and Acceleration of Electrons in Coma and Other Clusters of Galaxies
• Radio Halo and Relic Candidates from the NRAO VLA Sky Survey
• Cluster mergers and non-thermal phenomena: expectations from a statistical magneto-turbulent model
• Halo and Relic Sources in Clusters of Galaxies
• On The Origin of Radio Halos in Galaxy Clusters
• Alfvenic reacceleration of relativistic particles in galaxy clusters: MHD waves, leptons and hadrons
• Confirmation of non-thermal hard X-ray excess in the Coma cluster from two epoch observations
• The cluster M-T relation from temperature profiles observed with ASCA and ROSAT
• Alfvenic reacceleration of relativistic particles in galaxy clusters in the presence of secondary electrons and positrons
• Diagnostic Signatures of Radio and HXR Emission on Particle Acceleration Processes in the Coma Cluster
• Where does the hard X-ray diffuse emission in clusters of galaxies come from?

Cited by in corpus (4)

• Fast magnetic field amplification in distant galaxyclusters
• On the radio -- X-ray luminosity correlation of radio halos at low radio frequency - Application of the turbulent re-acceleration model
• The detection of cluster magnetic fields via radio source depolarisation
• uGMRT and MeerKAT observation of RXCJ0232-4420: a quiet cluster with a giant radio halo