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LoCuSS: first results from strong-lensing analysis of 20 massive galaxy clusters at z = 0.2

Richard, Johan and Smith, Graham P. and Kneib, Jean-Paul and Ellis, Richard S. and Sanderson, A. J. R. and Pei, L. and Targett, T. A. and Sand, D. J. and Swinbank, A. M. and Dannerbauer, H. and Mazzotta, P. and Limousin, M. and Egami, E. and Jullo, E. and Hamilton-Morris, V. and Moran, S. M. (2010) LoCuSS: first results from strong-lensing analysis of 20 massive galaxy clusters at z = 0.2. Monthly Notices of the Royal Astronomical Society, 404 (1). pp. 325-349. ISSN 0035-8711.

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We present a statistical analysis of a sample of 20 strong lensing clusters drawn from the Local Cluster Substructure Survey, based on high-resolution Hubble Space Telescope imaging of the cluster cores and follow-up spectroscopic observations using the Keck-I telescope. We use detailed parametrized models of the mass distribution in the cluster cores, to measure the total cluster mass and fraction of that mass associated with substructures within R ≤ 250 kpc. These measurements are compared with the distribution of baryons in the cores, as traced by the old stellar populations and the X-ray emitting intracluster medium. Our main results include: (i) the distribution of Einstein radii is lognormal, with a peak and 1σ width of〈log_(10)θ_E(z=2)〉= 1.16 ± 0.28; (ii) we detect an X-ray/lensing mass discrepancy of〈M_(SL)/M_X〉= 1.3 at 3σ significance – clusters with larger substructure fractions displaying greater mass discrepancies, and thus greater departures from hydrostatic equilibrium and (iii) cluster substructure fraction is also correlated with the slope of the gas density profile on small scales, implying a connection between cluster–cluster mergers and gas cooling. Overall our results are consistent with the view that cluster–cluster mergers play a prominent role in shaping the properties of cluster cores, in particular causing departures from hydrostatic equilibrium, and possibly disturbing cool cores. Our results do not support recent claims that large Einstein radius clusters present a challenge to the cold dark matter paradigm.

Item Type:Article
Related URLs:
URLURL TypeDescription DOIArticle
Richard, Johan0000-0001-5492-1049
Smith, Graham P.0000-0003-4494-8277
Kneib, Jean-Paul0000-0002-4616-4989
Ellis, Richard S.0000-0001-7782-7071
Sand, D. J.0000-0003-4102-380X
Dannerbauer, H.0000-0001-7147-3575
Mazzotta, P.0000-0002-5411-1748
Jullo, E.0000-0002-9253-053X
Moran, S. M.0000-0002-9194-5071
Additional Information:© 2010 The Authors. Journal compilation © 2010 RAS. Accepted 2010 January 4. Received 2009 December 17; in original form 2009 August 12. We thank our colleagues in the LoCuSS collaborations for much support, encouragement and help. We acknowledge useful discussions with Andrew Newman, Masmune Oguri, Arif Babul, Giovanni Covone, Timothy James, Alastair Edge and Ian Smail. We are grateful for Matt Lehnert, Christian Tapken and Nicole Nesvadba for their spectroscopic measurement of one of the systems. Mark Sullivan kindly observed long-slit data on A611 for us. JR acknowledges support from an EU Marie-Curie fellowship. GPS acknowledges support from the Royal Society and STFC. JPK acknowledges support from the CNRS, from the Agence Nationale de la Recherche grant ANR-06-BLAN-0067 and from the French–Israelian collaboration project07-AST-F9. AJRS acknowledges support from STFC. ML acknowledges the Centre National d’ Etudes Spatiales for their support. The Dark Cosmology Centre is funded by the Danish National Research Foundation. Results are partially based on observations made with the NASA/ESA HST and the Keck telescope. The authors recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Funding AgencyGrant Number
Marie Curie FellowshipUNSPECIFIED
Science and Technology Facilities Council (STFC)UNSPECIFIED
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Agence Nationale de la Recherche (ANR)ANR-06-BLAN-0067
French–Israelian collaboration project07-AST-F9
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Subject Keywords:gravitational lensing; galaxies: clusters: general
Issue or Number:1
Record Number:CaltechAUTHORS:20100604-143939025
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Official Citation:Johan, R., P. S. Graham, et al. (2010) LoCuSS: first results from strong-lensing analysis of 20 massive galaxy clusters at <i>z</i>= 0.2. Monthly Notices of the Royal Astronomical Society 325-349 DOI: 10.1111/j.1365-2966.2009.16274.x
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:18570
Deposited By: Tony Diaz
Deposited On:15 Jul 2010 20:28
Last Modified:09 Mar 2020 13:18

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