A shock front at the radio relic of Abell 2744. Issue 2 (16th June 2016)

• Record Type: Journal Article
• Authors: Eckert, D.; Jauzac, M.; Vazza, F.; Owers, M. S.; Kneib, J.-P.; Tchernin, C.; Intema, H.; Knowles, K.
• Is Part Of: Monthly notices of the Royal Astronomical Society. Volume 461:Issue 2(2016)
• Page Start: 1302
• Page End: 1307
• Publication Date: 2016-06-16
• Subjects: galaxies: clusters: individual: A2744 -- X-rays: galaxies: clusters; Astronomy -- Periodicals; Periodicals; 520.5
• DOI: 10.1093/mnras/stw1435
• Languages: English
• ISSNs: 0035-8711

Abstract

Abstract: Radio relics are Mpc-scale diffuse radio sources at the peripheries of galaxy clusters which are thought to trace outgoing merger shocks. We present XMM–Newton and Suzaku observations of the galaxy cluster Abell 2744 ( z = 0.306), which reveal the presence of a shock front 1.5 Mpc east of the cluster core. The surface-brightness jump coincides with the position of a known radio relic. Although the surface-brightness jump indicates a weak shock with a Mach number $\mathcal {M}=1.7_{-0.3}^{+0.5}$, the plasma in the post-shock region has been heated to a very high temperature (∼13 keV) by the passage of the shock wave. The low-acceleration efficiency expected from such a weak shock suggests that mildly relativistic electrons have been re-accelerated by the passage of the shock front.