SIMBAD references

2004A&A...423..111F - Astronomy and Astrophysics, volume 423, 111-119 (2004/8-3)

Spectral index maps of the radio halos in Abell 665 and Abell 2163.


Abstract (from CDS):

New radio data at 330 MHz are presented for the rich clusters Abell 665 and Abell 2163, whose radio emission is characterized by the presence of a radio halo. These images allowed us to derive the spectral properties of the two clusters under study. The integrated spectra of these halos between 0.3GHz and 1.4GHz are moderately steep: α1.40.3=1.04 and α1.40.3=1.18, for A665 and A2163, respectively. The spectral index maps, produced with an angular resolution of the order of ∼1', show features of the spectral index (flattening and patches), which are indication of a complex shape of the radiating electron spectrum, and are therefore in support of electron reacceleration models. Regions of flatter spectrum are found to be related to the recent merger activity in these clusters. This is the first strong confirmation that the cluster merger supplies energy to the radio halo. In the undisturbed cluster regions, the spectrum steepens with the distance from the cluster center. This is interpreted as the result of the combination of the magnetic field profile with the spatial distribution of the reacceleration efficiency, thus allowing us to set constraints on the radial profile of the cluster magnetic field.

Abstract Copyright:

Journal keyword(s): radio continuum: general - galaxies: clusters: general - galaxies: clusters: individual: A665 - galaxies: clusters: individual: A2163 - galaxies: intergalactic medium - X-rays: galaxies: clusters

Simbad objects: 8

goto Full paper

goto View the reference in ADS

To bookmark this query, right click on this link: simbad:2004A&A...423..111F and select 'bookmark this link' or equivalent in the popup menu


© Université de Strasbourg/CNRS

    • Contact