The Distribution of Dark and Luminous Matter in the Unique Galaxy Cluster Merger Abell 2146

Abstract

Abell 2146 ($z$ = 0.232) consists of two galaxy clusters undergoing a major merger. The system was discovered in previous work, where two large shock fronts were detected using the $\text{Chandra X-ray Observatory}$, consistent with a merger close to the plane of the sky, caught soon after first core passage. A weak gravitational lensing analysis of the total gravitating mass in the system, using the distorted shapes of distant galaxies seen with ACS-WFC on $\text{Hubble Space Telescope}$, is presented. The highest peak in the reconstruction of the projected mass is centred on the Brightest Cluster Galaxy (BCG) in Abell 2146-A. The mass associated with Abell 2146-B is more extended. Bootstrapped noise mass reconstructions show the mass peak in Abell 2146-A to be consistently centred on the BCG. Previous work showed that BCG-A appears to lag behind an X-ray cool core; although the peak of the mass reconstruction is centred on the BCG, it is also consistent with the X-ray peak given the resolution of the weak lensing mass map. The best-fit mass model with two components centred on the BCGs yields $M_{200}$ = 1.1${}_{-0.4}^{+0.3}$$\times$10${}^{15}$M${}_{\odot }$ and 3${}_{-2}^{+1}$$\times$10${}^{14}$M${}_{\odot }$ for Abell 2146-A and Abell 2146-B respectively, assuming a mass concentration parameter of $c=3.5$ for each cluster. From the weak lensing analysis, Abell 2146-A is the primary halo component, and the origin of the apparent discrepancy with the X-ray analysis where Abell 2146-B is the primary halo is being assessed using simulations of the merger.

12 pages, 9 figures, published in MNRAS

References in corpus (9)

• 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
• The impact of mergers on relaxed X-ray clusters - I. Dynamical evolution and emergent transient structures
• 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
• Why Do Only Some Galaxy Clusters Have Cool Cores?
• Simulating the Bullet Cluster
• Chandra observation of two shock fronts in the merging galaxy cluster Abell 2146

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• Constraining Merging Galaxy Clusters with X-ray and Lensing Simulations and Observations: The case of Abell 2146
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