Chandra and XMM-Newton observations of A2256: cold fronts, merger shocks, and constraint on the IC emission

Abstract

We present the results of deep Chandra and XMM-Newton observations of a complex merging galaxy cluster Abell 2256 (A2256) that hosts a spectacular radio relic (RR). The temperature and metallicity maps show clear evidence of a merger between the western subcluster (SC) and the primary cluster (PC). We detect five X-ray surface brightness edges. Three of them near the cluster center are cold fronts (CFs): CF1 is associated with the infalling SC; CF2 is located in the east of the PC; and CF3 is to the west of the PC core. The other two edges at cluster outskirts are shock fronts (SFs): SF1 near the RR in the NW has Mach numbers derived from the temperature and the density jumps, respectively, of $M_T=1.62\pm 0.12$ and $M_{\rho }=1.23\pm 0.06$; SF2 in the SE has $M_T=1.54\pm 0.05$ and $M_{\rho }=1.16\pm 0.13$. In the region of the RR, there is no evidence for the correlation between X-ray and radio substructures, from which we estimate an upper limit for the inverse-Compton emission, and therefore set a lower limit on the magnetic field ($\sim$ 450 kpc from PC center) of $B>1.0\mu$G for a single power-law electron spectrum or $B>0.4\mu$G for a broken power-law electron spectrum. We propose a merger scenario including a PC, an SC, and a group. Our merger scenario accounts for the X-ray edges, diffuse radio features, and galaxy kinematics, as well as projection effects.

15 pages, 12 figures, MNRAS in press

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Cited by in corpus (10)

• Radio footprints of a minor merger in the Shapley Supercluster: From supercluster down to galactic scales
• Deep low-frequency radio observations of Abell 2256 I: The filamentary radio relic
• Deep low-frequency radio observations of Abell 2256 II: The ultra-steep spectrum radio halo
• The role of physical and numerical viscosity in hydrodynamical instabilities
• AXES-SDSS: comparison of SDSS galaxy groups with all-sky X-ray extended sources
• Gas sloshing and cold fronts in pre-merging galaxy cluster Abell 98
• A formation mechanism for "Wrong Way" Radio Relics
• Probing particle acceleration in Abell 2256: from to 16 MHz to gamma rays
• The Merger Dynamics of the X-ray Emitting Plasma in Clusters of Galaxies
• The shocking features in the closest rich galaxy cluster Norma