Hubble Frontier Fields : the geometry and dynamics of the massive galaxy cluster merger MACSJ0416.1−2403

Jauzac, M.; Jullo, E.; Eckert, D.; Ebeling, H.; Richard, J.; Limousin, M.; Atek, H.; Kneib, J.-P.; Clément, B.; Egami, E.; Harvey, D.; Knowles, K.; Massey, R.; Natarajan, P.; Neichel, B.; Rexroth, M.

doi:10.1093/mnras/stu2425

Hubble Frontier Fields : the geometry and dynamics of the massive galaxy cluster merger MACSJ0416.1−2403

Jauzac, M.; Jullo, E.; Eckert, D.; Ebeling, H.; Richard, J.; Limousin, M.; Atek, H.; Kneib, J.-P.; Clément, B.; Egami, E.; Harvey, D.; Knowles, K.; Massey, R.; Natarajan, P.; Neichel, B.; Rexroth, M.

Authors

Professor Mathilde Jauzac mathilde.jauzac@durham.ac.uk
Professor

E. Jullo

D. Eckert

H. Ebeling

J. Richard

M. Limousin

H. Atek

J.-P. Kneib

B. Clément

E. Egami

D. Harvey

K. Knowles

Professor Richard Massey r.j.massey@durham.ac.uk
Professor

P. Natarajan

B. Neichel

M. Rexroth

Abstract

We use a joint optical/X-ray analysis to constrain the geometry and history of the ongoing merging event in the massive galaxy cluster MACSJ0416.1-2403 (z=0.397). Our investigation of cluster substructure rests primarily on a combined strong- and weak-lensing mass reconstruction based on the deep, high-resolution images obtained for the Hubble Frontier Fields initiative. To reveal the system's dynamics, we complement this lensing analysis with a study of the intra-cluster gas using shallow Chandra data, and a three-dimensional model of the distribution and motions of cluster galaxies derived from over 100 spectroscopic redshifts. The multi-scale grid model obtained from our combined lensing analysis extends the high-precision strong-lensing mass reconstruction recently performed to cluster-centric distances of almost 1 Mpc. Our analysis detects the two well known mass concentrations in the cluster core. A pronounced offset between collisional and collisionless matter is only observed for the SW cluster component, while excellent alignment is found for the NE cluster. Both the lensing analysis and the distribution of cluster light strongly suggest the presence of a third massive structure, almost 2 arcmin SW of the cluster centre. Since no X-ray emission is detected in this region, we conclude that this structure is non-virialised and speculate that it might be part of a large-scale filament almost aligned with our line of sight. Combining all evidence from the distribution of dark and luminous matter, we propose two alternative scenarios for the trajectories of the components of MACSJ0416.1-2403. Upcoming deep X-ray observations that allow the detection of shock fronts, cold cores, and sloshing gas (all key diagnostics for studies of cluster collisions) will allow us to test, and distinguish between these two scenarios.

Citation

Jauzac, M., Jullo, E., Eckert, D., Ebeling, H., Richard, J., Limousin, M., …Rexroth, M. (2015). Hubble Frontier Fields : the geometry and dynamics of the massive galaxy cluster merger MACSJ0416.1−2403. Monthly Notices of the Royal Astronomical Society, 446(4), 4132-4147. https://doi.org/10.1093/mnras/stu2425

Journal Article Type	Article
Acceptance Date	Nov 13, 2014
Online Publication Date	Dec 9, 2014
Publication Date	Feb 1, 2015
Deposit Date	Dec 10, 2014
Publicly Available Date	Feb 17, 2015
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	446
Issue	4
Pages	4132-4147
DOI	https://doi.org/10.1093/mnras/stu2425
Keywords	Gravitational lensing: strong, Gravitational lensing: weak, Galaxies: clusters: individual, Dark matter, X-rays: galaxies: clusters.

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Copyright Statement
This article has been accepted for publication in Monthly Notices of the Royal Astronomical Society ©: 2015 The Authors Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.