Limousin, M. and Richard, J. and Kneib, J.-P. and Brink, H. and Pelló, R. and Jullo, E. and Tu, H. and Sommer-Larsen, J. and Egami, E. and Michałowski, M. J. and Cabanac, R. and Stark, D. P. (2008) Strong lensing in Abell 1703: constraints on the slope of the inner dark matter distribution. Astronomy and Astrophysics, 489 (1). pp. 23-35. ISSN 0004-6361 http://resolver.caltech.edu/CaltechAUTHORS:LIMaanda08
- Published Version
See Usage Policy.
Use this Persistent URL to link to this item: http://resolver.caltech.edu/CaltechAUTHORS:LIMaanda08
Properties of dark matter haloes can be probed observationally and numerically, and comparing both approaches provides ways to constrain cosmological models. When it comes to the inner part of galaxy cluster scale haloes, interaction between the baryonic and the dark matter component is an important issue that is far from being fully understood. With this work, we aim to initiate a program coupling observational and numerical studies to probe the inner part of galaxy clusters. In this article, we apply strong lensing techniques on Abell 1703, a massive X-ray luminous galaxy cluster at z = 0.28. Our analysis is based on imaging data from both the space and ground in 8 bands, complemented by a spectroscopic survey. Abell 1703 is rather circular from the general shape of its multiply imaged systems and is dominated by a giant elliptical cD galaxy in its centre. This cluster exhibits a remarkable bright central ring formed by 4 images at z_(spec) = 0.888 only 5-13" away from the cD centre. This unique feature offers a rare lensing constrain for probing the central mass distribution. The stellar contribution from the cD galaxy (~1.25 x 10^1) M⊙ within 30 kpc) is accounted for in our parametric mass modelling, and the underlying smooth dark matter component distribution is described using a generalized NFW profile parametrized with a central logarithmic slope α. The rms of our mass model in the image plane is equal to 1.4". We find that within the range where observational constraints are present (from ~20 kpc to ~210 kpc), α is equal to 1.09^(+0.05)_(-0.11)(3σ confidence level). The concentration parameter is equal to c_(200) ~3.5, and the scale radius is constrained to be larger than the region where observational constraints are available (r_s = 730^(+15)_(-75) kpc). The 2D mass is equal to M(210 kpc) = 2.4 x 10^14 M⊙. However, we cannot draw any conclusions on cosmological models at this point since we lack results from realistic numerical simulations containing baryons to make a proper comparison. We advocate the need for a large sample of well observed (and well constrained) and simulated unimodal relaxed galaxy clusters in order to make reliable comparisons and to potentially provide a test of cosmological models.
|Additional Information:||© ESO 2008. Received 25 February 2008 / Accepted 12 July 2008. We thank many people for constructive comments and discussion related to this topic, in particular: Bernard Fort, Dave Sand, Hans Böhringer, Jens Hjorth, Kristian Pedersen, Steen Hansen. We thank John Stott for creating the colour image from which Fig. 1 has been made, and for allowing us to use it. The referee is acknowledged for a careful reading and a constructive report. M.L. acknowledges the Agence Nationale de la Recherche for its support, project number BLAN06-3-135448. The Dark Cosmology Center is funded by the Danish National Research Foundation. J.R. is grateful to Caltech for its support. J.P.K. aknowledges the Centre National de la Recherche Scientifique for its support. We thank the Danish Centre for Scientific Computing at the University of Copenhagen for providing us generous amount of time on its supercomputing facility. Based on data collected at Subaru Telescope, which is operated by the National Astronomical Observatory of Japan. We are thankful to Ichi Tanaka for his support in the reduction of MOIRCS imaging data. M.L. acknowledges the lensing group at Shanghai Normal University for their kind invitation and hospitality, during which this work has been initiated. 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.|
|Subject Keywords:||gravitational lensing; galaxies: clusters: individual: Abell 1703; dark matter|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Tony Diaz|
|Deposited On:||12 Aug 2009 20:04|
|Last Modified:||26 Dec 2012 10:51|
Repository Staff Only: item control page