We extend our analyses of the dark matter ( DM ) distribution in relaxed clusters to the case of Abell 383 , a luminous X-ray cluster at z =0.189 with a dominant central galaxy and numerous strongly-lensed features .
Following our earlier papers , we combine strong and weak lensing constraints secured with Hubble Space Telescope and Subaru imaging with the radial profile of the stellar velocity dispersion of the central galaxy , essential for separating the baryonic mass distribution in the cluster core .
Hydrostatic mass estimates from Chandra X-ray observations further constrain the solution .
These combined datasets provide nearly continuous constraints extending from 2 kpc to 1.5 Mpc in radius , allowing stringent tests of results from recent numerical simulations .
Two key improvements in our data and its analysis make this the most robust case yet for a shallow slope \beta of the DM density profile \rho _ { { DM } } \propto r ^ { - \beta } on small scales .
First , following deep Keck spectroscopy , we have secured the stellar velocity dispersion profile to a radius of 26 kpc for the first time in a lensing cluster .
Secondly , we improve our previous analysis by adopting a triaxial DM distribution and axisymmetric dynamical models .
We demonstate that in this remarkably well-constrained system , the logarithmic slope of the DM density at small radii is \beta < 1.0 ( 95 % confidence ) .
An improved treatment of baryonic physics is necessary , but possibly insufficient , to reconcile our observations with the recent results of high-resolution simulations .