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Keck spectroscopic survey of strongly lensed galaxies in Abell 1703: further evidence of a relaxed, unimodal cluster

Richard, J. and Pei, L. and Limousin, M. and Jullo, E. and Kneib, J. P. (2009) Keck spectroscopic survey of strongly lensed galaxies in Abell 1703: further evidence of a relaxed, unimodal cluster. Astronomy and Astrophysics, 498 (1). pp. 37-47. ISSN 0004-6361.

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Context. Strong gravitational lensing is a unique tool that can be used to accurately model the inner mass distribution of massive galaxy clusters. In particular, clusters with large Einstein radii provide a wealth of multiply imaged systems in the cluster core. Measuring the redshift of these multiple images provides strong constraints for precisely determining the shape of the central dark matter profile. Aims. This paper presents a spectroscopic survey of strongly lensed galaxies in the massive cluster lens Abell 1703, which displays a large Einstein radius (28" at z = 2.8) and numerous strongly-lensed systems including a central ring-like configuration. Methods. We used the LRIS spectrograph on Keck to target multiple images and lensed galaxy candidates, and used the measured spectroscopic redshifts to constrain the mass distribution of the cluster using a parametric model. Results. The spectroscopic data enable us to measure accurate redshifts for 7 sources at z > 2 , all of which are in good agreement with their photometric redshifts. We update the identification of multiply imaged systems by discovering 3 new systems and identifying a radial counter image. We also report the discovery of a remarkably bright ~3.6 L∗ i-band dropout at z = 5.827 in our mask and it is only moderately magnified by the cluster (μ ~ 3.0 ± 0.08). The improved parametric mass model, including 16 multiple systems with 10 spectroscopic redshifts, further constrains the smooth cluster-scale mass distribution with a generalized NFW profile of best-fit logarithmic slope α = 0.92 ± 0.04, concentration c_(200) = 4.72 ± 0.40 and scale radius r_s = 476 ± 45 kpc. The overall rms in the image plane is 1.3". Conclusions. Our strong-lensing model allows us to predict a large-scale shear signal that is consistent with weak-lensing measurements inferred from Subaru data out to 4 Mpc h^(−1). Also considering the strong-lensing modeling requires a single dark matter clump, this suggests that Abell 1703 is a relaxed, unimodal cluster. This unique cluster could be probed further using deep X-ray, SZ, and dynamics analysis for a detailed study of the physics in a relaxed cluster.

Item Type:Article
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Richard, J.0000-0001-5492-1049
Jullo, E.0000-0002-9253-053X
Kneib, J. P.0000-0002-4616-4989
Additional Information:© ESO 2009. Received 17 November 2008 / Accepted 30 January 2009. We thank the anonymous referee for his/her helpful comments, and acknowledge useful discussions with Masamune Oguri, Carlos Frenk, and Mark Swinbank. J.R. acknowledges support from an European Union Marie-Curie Fellowship. M.L. acknowledges the Agence Nationale de la Recherche for its support, project number 06-BLAN-0067. The Dark Cosmology Center is funded by the Danish National Research Foundation. We thank the Danish Centre for Scientific Computing at the University of Copenhagen for providing a generous amount of time on its supercomputing facility. J.P.K. acknowledges the Centre National de la Recherche Scientifique for its support. 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
Agence Nationale pour la Recherche (ANR)06-BLAN-0067
Danish National Research FoundationUNSPECIFIED
Centre National de la Recherche Scientifique (CNRS)UNSPECIFIED
Subject Keywords:galaxies : high-redshift; galaxies: distances and redshifts; galaxies: clusters: individual: Abell 1703; gravitational lensing
Issue or Number:1
Record Number:CaltechAUTHORS:20090901-092408787
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Official Citation:Keck spectroscopic survey of strongly lensed galaxies in Abell 1703: further evidence of a relaxed, unimodal cluster J. Richard, L. Pei, M. Limousin, E. Jullo and J. P. Kneib A&A 498 (1) 37-47 (2009) DOI: 10.1051/0004-6361/200811366.
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:15511
Deposited By: Tony Diaz
Deposited On:04 Sep 2009 15:55
Last Modified:09 Mar 2020 13:18

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