The Entire Virial Radius of the Fossil Cluster RXJ1159+5531: I. Gas Properties

Abstract

Previous analysis of the fossil-group/cluster RXJ1159+5531 with X-ray observations from a central Chandra pointing and an offset-North Suzaku pointing indicate a radial intracluster medium (ICM) entropy profile at the virial radius ($R_{\mathrm{vir}}$) consistent with predictions from gravity-only cosmological simulations, in contrast to other cool-core clusters. To examine the generality of these results, we present three new Suzaku observations that, in conjunction with the North pointing, provide complete azimuthal coverage out to $R_{\mathrm{vir}}$. With two new Chandra ACIS-I observations overlapping the North Suzaku pointing, we have resolved $\gtrsim$50\% of the cosmic X-ray background there. We present radial profiles of the ICM density, temperature, entropy, and pressure obtained for each of the four directions. We measure only modest azimuthal scatter in the ICM properties at $R_{200}$ between the Suzaku pointings: 7.6\% in temperature and 8.6\% in density, while the systematic errors can be significant. The temperature scatter, in particular, is lower than that studied at $R_{200}$ for a small number of other clusters observed with Suzaku. These azimuthal measurements verify that RXJ1159+5531 is a regular, highly relaxed system. The well-behaved entropy profiles we have measured for RXJ1159+5531 disfavor the weakening of the accretion shock as an explanation of the entropy flattening found in other cool-core clusters but is consistent with other explanations such as gas clumping, electron-ion non-equilibrium, non-thermal pressure support, and cosmic ray acceleration. Finally, we mention that the large-scale galaxy density distribution of RXJ1159+5531 seems to have little impact on its gas properties near $R_{\mathrm{vir}}$.

Accepted for publication in ApJ

References in corpus (8)

• Baryons at the Edge of the X-ray Brightest Galaxy Cluster
• Temperature profiles of a representative sample of nearby X-ray galaxy clusters
• Probing the Dark Matter and Gas Fraction in Relaxed Galaxy Groups with X-ray observations from Chandra and XMM
• X-ray observations of the galaxy cluster PKS 0745-191: To the virial radius, and beyond
• The Magnetothermal Instability in the Intracluster Medium
• Weighing the Quiescent Central Black Hole in an Elliptical Galaxy with X-ray Emitting Gas
• Gas Loss in Simulated Galaxies as They Fall into Clusters
• Temperature and Entropy Profiles to the Virial Radius of Abell 1246 Cluster Observed with Suzaku

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