Hubble Space Telescope Observations of a Spectacular New Strong-Lensing Galaxy Cluster: MACS J1149.5+2223 at z = 0.544 - CNRS - Centre national de la recherche scientifique Accéder directement au contenu
Article Dans Une Revue The Astrophysical journal letters Année : 2009

Hubble Space Telescope Observations of a Spectacular New Strong-Lensing Galaxy Cluster: MACS J1149.5+2223 at z = 0.544

Résumé

We present Advanced Camera for Surveys observations of MACS J1149.5+2223, an X-ray luminous galaxy cluster at z = 0.544 discovered by the Massive Cluster Survey. The data reveal at least seven multiply imaged galaxies, three of which we have confirmed spectroscopically. One of these is a spectacular face-on spiral galaxy at z = 1.491, the four images of which are gravitationally magnified by 8 lsim μ lsim 23. We identify this as an L sstarf (MB sime -20.7), disk-dominated (B/T lsim 0.5) galaxy, forming stars at ~6 M sun yr-1. We use a robust sample of multiply imaged galaxies to constrain a parameterized model of the cluster mass distribution. In addition to the main cluster dark matter halo and the bright cluster galaxies, our best model includes three galaxy-group-sized halos. The relative probability of this model is P(N halo = 4)/P(N halo < 4) >= 1012 where N halo is the number of cluster/group-scale halos. In terms of sheer number of merging cluster/group-scale components, this is the most complex strong-lensing cluster core studied to date. The total cluster mass and fraction of that mass associated with substructures within R <= 500 kpc, are measured to be M tot = (6.7 ± 0.4) × 1014 M sun and f sub = 0.25 ± 0.12, respectively. Our model also rules out recent claims of a flat density profile at gsim7σ confidence, thus highlighting the critical importance of spectroscopic redshifts of multiply imaged galaxies when modeling strong-lensing clusters. Overall our results attest to the efficiency of X-ray selection in finding the most powerful cluster lenses, including complicated merging systems.

Dates et versions

hal-00660854 , version 1 (17-01-2012)

Identifiants

Citer

Graham P. Smith, Harald Ebeling, Marceau Limousin, Jean-Paul Kneib, A. M. Swinbank, et al.. Hubble Space Telescope Observations of a Spectacular New Strong-Lensing Galaxy Cluster: MACS J1149.5+2223 at z = 0.544. The Astrophysical journal letters, 2009, 707, pp.L163-L168. ⟨10.1088/0004-637X/707/2/L163⟩. ⟨hal-00660854⟩
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