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We present a reconstruction of the mass distribution of galaxy cluster Abell 1689 at z = 0.18 using detected strong lensing features from deep ACS observations and extensive ground based spectroscopy. Earlier analyses have reported up to 32 multiply imaged systems in this cluster, of which only 3 were spectroscopically confirmed. In this work, we present a parametric strong lensing mass reconstruction using 34 multiply imaged systems of which 24 have newly determined spectroscopic redshifts, which is a major step forward in building a robust mass model. In turn, the new spectroscopic data allows a more secure identification of multiply imaged systems. The resultant mass model enables us to reliably predict the redshifts of additional multiply imaged systems for which no spectra are currently available, and to use the location of these systems to further constrain the mass model. Using our strong lensing mass model, we predict on larger scale a shear signal which is consistent with that inferred from our large scale weak lensing analysis derived using CFH12K wide field images. Thanks to a new method for reliably selecting a well defined background lensed galaxy population, we resolve the discrepancy found between the NFW concentration parameters derived from earlier strong and weak lensing analysis. The derived parameters for the best fit NFW profile is found to be c200 = 7.6 +- 1.6 and r200 = 2.16 +- 0.10 himg1.gif Mpc (corresponding to a 3D mass equal to M200 = [1.32 +- 0.2] x 1015 h70 M). The large number of new constraints incorporated in this work makes Abell 1689 the most reliably reconstructed cluster to date. This well calibrated mass model, which we here make publicly available, will enable us to exploit Abell 1689 efficiently as a gravitational telescope, as well as to potentially constrain cosmology.

We present a comprehensive lensing analysis of the rich cluster Cl 0024+1654 (z = 0.395) based on panoramic sparse-sampled imaging conducted with the WFPC2 and STIS cameras on board the Hubble Space Telescope. By comparing higher fidelity signals in the limited STIS data with the wider field data available from WFPC2, we demonstrate an ability to detect reliably weak-lensing signals to a cluster radius of [?]5 himg1.gif Mpc, where the mean shear is around 1%. This enables us to study the distribution of dark matter with respect to the cluster light over an unprecedented range of cluster radii and environments. The projected mass distribution reveals a secondary concentration representing 30% of the overall cluster mass, which is also visible in the distribution of cluster member galaxies. We develop a method to derive the projected mass profile of the main cluster taking into account the influence of the secondary clump. We normalize the mass profile determined from the shear by assuming that background galaxies selected with 23 < I < 26 have a redshift distribution statistically similar to that inferred photometrically in the Hubble Deep Fields. The total mass within the central region of the cluster is independently determined from strong-lensing constraints according to a detailed model that utilizes the multiply imaged arc at z = 1.675. Combining strong and weak constraints, we are able to probe the mass profile of the cluster on scales of 0.1-5 Mpc, thus providing a valuable test of the universal form proposed by Navarro, Frenk, & White (NFW) on large scales. A generalized power-law fit indicates an asymptotic three-dimensional density distribution of r [?] r-n with n > 2.4. An isothermal mass profile is therefore strongly rejected, whereas an NFW profile with M200 = 6.1img2.gif x 1014 himg1.gif M provides a good fit to the lensing data. We isolate cluster members according to their optical/near-infrared colors; the red cluster light closely traces the dark matter with a mean mass-to-light ratio of M/LK = 40 +- 5 h65 M/L. Similar profiles for mass and light on 1-5 Mpc scales are expected if cluster assembly is largely governed by infalling groups.