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

King, L.J.; Clowe, D.I.; Coleman, J.E.; Russell, H.R.; Santana, R.; White, J.A.; Canning, R.E.A.; Deering, N.J.; Fabian, A.C.; Lee, B.E.; Li, B.; McNamara, B.R.

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


L.J. King

D.I. Clowe

J.E. Coleman

H.R. Russell

R. Santana

J.A. White

R.E.A. Canning

N.J. Deering

A.C. Fabian

B.E. Lee

B.R. McNamara


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 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 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 M200 = 1.1×1015 M⊙ and 3[Math Processing Error]×1014 M⊙ 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.


King, L., Clowe, D., Coleman, J., Russell, H., Santana, R., White, J., …McNamara, B. (2016). The Distribution of Dark and Luminous Matter in the Unique Galaxy Cluster Merger Abell 2146. Monthly Notices of the Royal Astronomical Society, 459(1), 517-527.

Journal Article Type Article
Acceptance Date Mar 1, 2016
Online Publication Date Mar 7, 2016
Publication Date Jun 11, 2016
Deposit Date Apr 5, 2016
Publicly Available Date Apr 22, 2016
Journal Monthly Notices of the Royal Astronomical Society
Print ISSN 0035-8711
Electronic ISSN 1365-2966
Publisher Royal Astronomical Society
Peer Reviewed Peer Reviewed
Volume 459
Issue 1
Pages 517-527
Public URL


Published Journal Article (3.5 Mb)

Copyright Statement
This article has been accepted for publication in Monthly notices of the Royal Astronomical Society ©: 2016 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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