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arXiv · 1009.4699

Galaxy Clusters in the Swift/BAT era II: 10 more Clusters detected above 15 keV

M. Ajello·P. Rebusco·N. Cappelluti·O. Reimer·H. Boehringer·V. La Parola·G. Cusumano
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Abstract

We report on the discovery of 10 additional galaxy clusters detected in the ongoing Swift/BAT all-sky survey. Among the newly BAT-discovered clusters there are: Bullet, Abell 85, Norma, and PKS 0745-19. Norma is the only cluster, among those presented here, which is resolved by BAT. For all the clusters we perform a detailed spectral analysis using XMM-Newton and Swift/BAT data to investigate the presence of a hard (non-thermal) X-ray excess. We find that in most cases the clusters' emission in the 0.3-200keV band can be explained by a multi-temperature thermal model confirming our previous results. For two clusters (Bullet and Abell 3667) we find evidence for the presence of a hard X-ray excess. In the case of the Bullet cluster, our analysis confirms the presence of a non-thermal, power-law like, component with a 20-100 keV flux of 3.4 \times 10-12 erg cm-2 s-1 as detected in previous studies. For Abell 3667 the excess emission can be successfully modeled as a hot component (kT=~13keV). We thus conclude that the hard X-ray emission from galaxy clusters (except the Bullet) has most likely thermal origin.

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M. Ajello, P. Rebusco, N. Cappelluti, O. Reimer, H. Boehringer, V. La Parola, G. Cusumano. 2010-09-23. Galaxy Clusters in the Swift/BAT era II: 10 more Clusters detected above 15 keV. https://doi.org/10.1088/0004-637x%2F725%2F2%2F1688

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