paper

A Wide Field Hubble Space Telescope Study of the Cluster Cl0024+1654 at z=0.4 II: The Cluster Mass Distribution

arXiv:astro-ph/0307299 · doi:10.1086/378633

Abstract

(abridged) We present a comprehensive lensing analysis of the rich cluster Cl0024+1654 based on panoramic sparse-sampled imaging conducted with HST. We demonstrate an ability to detect reliably weak lensing signals to a cluster radius of ~5 Mpc where the mean shear is around 1%. 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 normalize the mass profile determined from the shear by assuming that background galaxies selected with I=23-26 have a redshift distribution statistically similar to that in the HDFs. Combining strong and weak constraints, we are able to probe the mass profile of the cluster on scales of 0.1 to 5 Mpc thus providing a valuable test of the universal form proposed by NFW on large scales. A generalized power law fit indicates a asymptotic density distribution with 3D slope larger than 2.4. An isothermal mass profile is therefore strongly rejected, whereas a NFW profile with M_200= 6.1+/-1 10^14 M_sun 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/L_K~ 40 M/L_sun. Similar profiles for mass and light on 1-5 Mpc scales are expected if cluster assembly is largely governed by infalling groups.

arXiv commentTo appear in ApJ v597 n2 (November 10, 2003 issue), higher resolution version at http://www.astro.caltech.edu/~tt/0024/

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