Magnetic field in galaxy clusters from depolarization of radio sources.
Abstract
We present a new approach to investigate the average properties of the magnetic field in the intra-cluster medium (ICM), and to search for possible correlations with the thermal properties of the ICM and cluster radio emission. We have selected a sample of 33 massive galaxy clusters from the HIghest X-ray FLUx Galaxy Cluster Sample, and used Northern VLA Sky Survey data to analyze the fractional polarization (F_p) of radio sources out to 10 core radii from the cluster centers. We detect a trend of F_p versus the projected distance from the cluster center. Such a trend can be reproduced by a magnetic field model with central values of a few mu G. The logrank statistical test indicates that there are no differences in the depolarization trend observed in clusters with and without radio halo, while the same test indicates significant differences in depolarization trend of sources in clusters with and without cool core. Although the role of the gas density should be better accounted for, these results are important for establishing a link between cluster magnetic fields, cool cores and radio halos.
- Publication:
-
Memorie della Societa Astronomica Italiana
- Pub Date:
- 2011
- Bibcode:
- 2011MmSAI..82..654B
- Keywords:
-
- Galaxy: clusters;
- general;
- Methods: observational;
- statistical;
- Intergalactic medium;
- Magnetic fields;
- Non-thermal