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Strong lensing by a node of the cosmic web - The core of MACS J0717.5+3745 at z = 0.55

Limousin, M. and Ebeling, H. and Richard, J. and Swinbank, A. M. and Smith, G. P. and Jauzac, M. and Rodionov, S. and Ma, C.-J. and Smail, I. and Edge, A. C. and Jullo, E. and Kneib, J.-P. (2012) Strong lensing by a node of the cosmic web - The core of MACS J0717.5+3745 at z = 0.55. Astronomy and Astrophysics, 544 . Art. No. A71. ISSN 0004-6361.

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We present results of a strong-lensing analysis of MACS J0717.5+3745 (hereafter MACS J0717), an extremely X-ray luminous galaxy cluster at z = 0.55. Observations at different wavelengths reveal a complex and dynamically very active cluster, whose core is connected to a large scale filament extended over several Mpc. Using multi-passband imaging data obtained with the Hubble Space Telescope’s Advanced Camera for Surveys (ACS), we identify 15 multiply imaged systems across the full field of view of ACS, five of which we confirmed spectroscopically in ground-based follow-up observations with the Keck telescope. We use these multiply imaged systems to constrain a parametric model of the mass distribution in the cluster core, employing a new parallelized version of the Lenstool software. The main result is that the most probable description of the mass distribution comprises four clusterscale dark matter haloes. The total mass distribution follows the light distribution but strongly deviates from the distribution of the intra-cluster gas as traced by the X-ray surface brightness. This confirms the complex morphology proposed by previous studies. We interpret this segregation of collisional and collisionless matter as strong evidence of multiple mergers and ongoing dynamical activity. MACS J0717 thus constitutes one of the most disturbed clusters presently known and, featuring a projected mass within the ACS field of view (R = 150” = 960 kpc) of 2.11 ± 0.23 × 10^(15) M_⊙, the system is also one of the most massive known.

Item Type:Article
Related URLs:
URLURL TypeDescription DOIArticle
Richard, J.0000-0001-5492-1049
Smith, G. P.0000-0003-4494-8277
Smail, I.0000-0003-3037-257X
Jullo, E.0000-0002-9253-053X
Kneib, J.-P.0000-0002-4616-4989
Additional Information:© 2012 ESO. Received 20 August 2011; Accepted 4 June 2012. Published online 30 July 2012. Based on observations obtained with the Hubble Space Telescope (HST) and the Keck Telescope. M.L. thanks Massimo Meneghetti and Adi Zitrin for helpful discussions. M.L. and J.P.K. acknowledge the Centre National de la Recherche Scientifique for its support. H.E. acknowledges financial support from STScI grants GO-09722 and GO-10420 as well as SAO grant GO3-4168X. The Dark Cosmology Centre is funded by the Danish National Research Foundation. This work has been conducted using facilities offered by CeSAM (Centre de donnéeS Astrophysiques de Marseille,
Funding AgencyGrant Number
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Danish National Research FoundationUNSPECIFIED
Smithsonian Astrophysical ObservatoryUNSPECIFIED
Subject Keywords:gravitational lensing: strong – galaxies: clusters: individual: MACS J0717.5+3745 – large-scale structure of Universe – dark matter
Record Number:CaltechAUTHORS:20121005-152321699
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:34722
Deposited By: Tony Diaz
Deposited On:10 Oct 2012 18:11
Last Modified:09 Mar 2020 13:18

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