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The Dark Matter Distribution in A383: Evidence for a Shallow Density Cusp from Improved Lensing, Stellar Kinematic, and X-ray Data

Newman, Andrew B. and Treu, Tommaso and Ellis, Richard S. and Sand, David J. (2011) The Dark Matter Distribution in A383: Evidence for a Shallow Density Cusp from Improved Lensing, Stellar Kinematic, and X-ray Data. Astrophysical Journal Letters, 728 (2). L39. ISSN 2041-8205.

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We extend our analyses of the dark matter (DM) distribution in relaxed clusters to the case of A383, 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 data sets 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 β of the DM density profile ρDM ∝ r^(–β) 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. Second, we improve our previous analysis by adopting a triaxial DM distribution and axisymmetric dynamical models. We demonstrate that in this remarkably well-constrained system, the logarithmic slope of the DM density at small radii is β < 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.

Item Type:Article
Related URLs:
URLURL TypeDescription
Newman, Andrew B.0000-0001-7769-8660
Treu, Tommaso0000-0002-8460-0390
Ellis, Richard S.0000-0001-7782-7071
Sand, David J.0000-0003-4102-380X
Additional Information:© 2011 American Astronomical Society. Received 2010 November 15; accepted 2011 January 14; published 2011 February 1. It is a pleasure to thank Steve Allen for providing his X-ray analysis and to acknowledge the helpful assistance of Eric Jullo, Johan Richard, Jean-Paul Kneib, and Satoshi Miyazaki. We thank the referee, Marceau Limousin, for his constructive suggestions. R.S.E. acknowledges financial support from DOE grant DE-SC0001101. Research support by the Packard Foundation is gratefully acknowledged by T.T. The authors recognize and acknowledge the cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain.
Funding AgencyGrant Number
Department of Energy (DOE)DE-SC0001101
David and Lucile Packard FoundationUNSPECIFIED
Subject Keywords:dark matter; galaxies: clusters: individual (A383); gravitational lensing: strong; gravitational lensing: weak; stars: kinematics and dynamics; X-rays: galaxies: clusters
Issue or Number:2
Classification Code:PACS: 98.65.Cw; 98.62.Lv; 98.62.Sb; 95.35.+d
Record Number:CaltechAUTHORS:20110315-142832310
Persistent URL:
Official Citation:Andrew B. Newman et al. 2011 ApJ 728 L39 doi: 10.1088/2041-8205/728/2/L39
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:22906
Deposited By: Jason Perez
Deposited On:16 Mar 2011 21:50
Last Modified:03 Oct 2019 02:41

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