Tam, S.-I. and Jauzac, M. and Massey, R. and Harvey, D. and Eckert, D. and Ebeling, H. and Ellis, R. S. and Ghirardini, V. and Klein, B. and Kneib, J.-P. and Lagattuta, D. and Natarajan, P. and Robertson, A. and Smith, G. P. (2020) 'The distribution of dark matter and gas spanning 6 Mpc around the post-merger galaxy cluster MS 0451-03.', Monthly notices of the Royal Astronomical Society., 496 (3). pp. 4032-4050.
Using the largest mosaic of Hubble Space Telescope images around a galaxy cluster, we map the distribution of dark matter throughout an ∼6 × 6 Mpc2 area centred on the cluster MS 0451−03 (z = 0.54, M200=1.65×1015M⊙). Our joint strong- and weak-lensing analysis shows three possible filaments extending from the cluster, encompassing six group-scale substructures. The dark matter distribution in the cluster core is elongated, consists of two distinct components, and is characterized by a concentration parameter of c200 = 3.79 ± 0.36. By contrast, XMM–Newton observations show the gas distribution to be more spherical, with excess entropy near the core, and a lower concentration of c200=2.35+0.89−0.70 (assuming hydrostatic equilibrium). Such a configuration is predicted in simulations of major mergers 2–7 Gyr after the first core passage, when the two dark matter haloes approach second turnaround, and before their gas has relaxed. This post-merger scenario finds further support in optical spectroscopy of the cluster’s member galaxies, which shows that star formation was abruptly quenched 5 Gyr ago. MS 0451−03 will be an ideal target for future studies of the growth of structure along filaments, star formation processes after a major merger, and the late-stage evolution of cluster collisions.
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|Publisher Web site:||https://doi.org/10.1093/mnras/staa1828|
|Publisher statement:||This article has been accepted for publication in Monthly notices of the Royal Astronomical Society. ©: 2020 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.|
|Date accepted:||15 June 2020|
|Date deposited:||22 October 2020|
|Date of first online publication:||26 June 2020|
|Date first made open access:||22 October 2020|
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