AAS 201st Meeting, January, 2003
Session 58. Clusters of Galaxies at Many Wavelengths
Oral, Tuesday, January 7, 2003, 10:00-11:30am, 608-609

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[58.07] The Matter Distribution in Galaxy Clusters

D.J. Sand, T. Treu, R.S. Ellis (Caltech)

One of the basic predictions of the Cold Dark Matter (CDM) picture of structure formation is that the density profiles of DM halos are universal in form across a wide range of mass scales from dwarf galaxies to clusters of galaxies. To test this prediction at the galaxy cluster scale, we have developed a method to determine the luminous and dark matter distribution in the inner regions of clusters with giant arcs around a central brightest cluster galaxy (BCG) using a lensing analysis and the velocity dispersion profile of the BCG to put very tight constraints on the matter density profile. A search of the entire HST archive for galaxy clusters with both a dominant, relatively isolated BCG and nearby giant gravitational arcs suitable for this task has been completed. Not only has this search yielded well over a dozen suitable systems, but it has also uncovered many other possible lensing features (some of which have been confirmed spectroscopically). Here we will present the results from the archive search and talk about the first three galaxy clusters studied in detail: MS2137, R1133, and Abell 383. All three have both tangential and radial gravitational arcs, allowing for a very accurate measurement of the controversial inner slope of dark matter halos, and hence a stringent test of CDM.

The author(s) of this abstract have provided an email address for comments about the abstract: djs@astro.caltech.edu

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