Chandra Observations of the Spectacular A3411-12 Merger Event

Abstract

We present deep Chandra observations of A3411-12, a remarkable merging cluster that hosts the most compelling evidence for electron re-acceleration at cluster shocks to date. Using the $Y_X-M$ scaling relation, we find $r_{500}\sim 1.3$ Mpc, $M_{500}=(7.1\pm 0.7)\times 10^{14}{M}_{\odot }$, $kT=6.5\pm 0.1$ keV, and a gas mass of $M_{\mathrm{g},500}=(9.7\pm 0.1)\times 10^{13}{M}_{\odot }$. The gas mass fraction within $r_{500}$ is $f_{\mathrm{g}}=0.14\pm 0.01$. We compute the shock strength using density jumps to conclude that the Mach number of the merging subcluster is small ($M\le 1.15_{-0.09}^{+0.14}$). We also present pseudo-density, projected temperature, pseudo-pressure, and pseudo-entropy maps. Based on the pseudo-entropy map we conclude that the cluster is undergoing a mild merger, consistent with the small Mach number. On the other hand, radio relics extend over Mpc scale in the A3411-12 system, which strongly suggests that a population of energetic electrons already existed over extended regions of the cluster.

23 pages, 17 figures, 4 tables. Accepted for publication in ApJ

References in corpus (20)

• A direct empirical proof of the existence of dark matter
• Constraints on the Self-Interaction Cross-Section of Dark Matter from Numerical Simulations of the Merging Galaxy Cluster 1E 0657-5
• Shocks and cold fronts in galaxy clusters
• Chandra temperature profiles for a sample of nearby relaxed galaxy clusters
• Diffuse Radio Emission from Galaxy Clusters
• Particle Acceleration on Megaparsec Scales in a Merging Galaxy Cluster
• Strong and weak lensing united III: Measuring the mass distribution of the merging galaxy cluster 1E0657-56
• Revealing the properties of dark matter in the merging cluster MACSJ0025.4-1222
• Draping of Cluster Magnetic Fields over Bullets and Bubbles -- Morphology and Dynamic Effects
• The speed of the `bullet' in the merging galaxy cluster 1E0657-56
• Contour binning: a new technique for spatially-resolved X-ray spectroscopy applied to Cassiopeia A
• The Case for Electron Re-Acceleration at Galaxy Cluster Shocks
• Magnetic draping of merging cores and radio bubbles in clusters of galaxies
• The rise and fall of star-formation in $\mathbf{z}\sim 0.2$ merging galaxy clusters
• MC${}^2$: Boosted AGN and star-formation activity in CIZA J2242.8+5301, a massive post-merger cluster at z=0.19
• Shock Waves and Cosmic Ray Acceleration in the Outskirts of Galaxy Clusters
• Star formation efficiency in galaxy clusters
• A large H$\alpha$ survey of star formation in relaxed and merging galaxy cluster environments at $z\sim 0.15-0.3$
• Dark Matter Subhalos and the X-ray Morphology of the Coma Cluster
• No Shock Across Part of a Radio Relic in the Merging Galaxy Cluster ZwCl 2341.1+0000?

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• On the detection of multiple shock fronts in A1914 using deep Chandra X-ray observations
• The application of the adiabatic compression scenario to the radio relic in the galaxy cluster Abell 3411-3412