Argelander-Institut für Astronomie, Auf dem Hügel 71, 53121 Bonn, Germany e-mail: email@example.com
2 European Southern Observatory, Karl-Schwarzschild-Strasse 2 85748 Garching bei München, Germany
3 Kavli Institute for Particle Astrophysics and Cosmology,2575 Sand Hill Rd. MS29, Menlo Park, CA 94025, USA
4 Department of Physics, University of California, Santa Barbara, CA 93106, USA
Accepted: 7 January 2008
Aims.We determine the central mass distribution of galaxy cluster RX J1347-1145 using strong gravitational lensing.
Methods.High-resolution HST/ACS images of the galaxy cluster RX J1347-1145 have enabled us to identify several new multiple-image candidates in the cluster, including a 5-image system with a central image. The multiple-images allow us to construct an accurate 2-dimensional mass map of the central part of the cluster. The modelling of the cluster mass includes the most prominent cluster galaxies modelled as truncated isothermal spheres and a smooth halo component that is described with 2 parametric profiles. The mass reconstruction is done using a Markov chain Monte Carlo method that provides us with a total projected mass density, as well as with estimates for the parameters of interest and their respective errors.
Results.Inside the Einstein radius of the cluster (~35'', or ~200 kpc, for a source at redshift 1.8), we obtain a total mass of (2.6 ± 0.1) 10. The mass profile of the cluster is well-fitted by both a Navarro, Frenk, and White profile with a moderate concentration of c = 5.3 and r200 = 3.3 Mpc, and a non-singular isothermal sphere with velocity dispersion σ = 1949 ± 40 km s-1 and a core radius of rc = 20 ± 2''. The mass profile agrees with previous mass estimates based on the X-ray emission from the hot intra-cluster gas, although the X-ray mass estimates are systematically lower than what we obtain with gravitational lensing.
Key words: gravitational lensing / galaxies: clusters: individual: RX J1347-1145 / galaxies: clusters: general / cosmology: dark matter
Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the data archives at the Space Telescope European Coordinating Facility and the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555.
© ESO, 2008