Natarajan, Priyamvada and Kneib, Jean-Paul and Smail, Ian and Treu, Tommaso and Ellis, Richard and Moran, Sean and Limousin, Marceau and Czoske, Oliver (2009) The Survival of Dark Matter Halos in the Cluster Cl 0024+16. Astrophysical Journal, 693 (1). pp. 970-983. ISSN 0004-637X http://resolver.caltech.edu/CaltechAUTHORS:20090918-111112480
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Theories of structure formation in a cold dark matter dominated universe predict that massive clusters of galaxies assemble from the hierarchical merging of lower mass subhalos. Exploiting strong and weak gravitational lensing signals inferred from panoramic Hubble Space Telescope imaging data, we present a high-resolution reconstruction of the mass distribution in the massive, lensing cluster Cl 0024+16 at z = 0.39. Applying galaxy-galaxy lensing techniques we track the fate of dark matter subhalos as a function of projected cluster-centric radius out to 5 Mpc, well beyond the virial radius. We report the first detection of the statistical lensing signal of dark matter subhalos associated with late-type galaxies in clusters. The mass of a fiducial dark matter halo that hosts an early-type L^* galaxy varies from M = 6.3^(+2.7)_(–2.0) × 10^(11)M_☉ within r < 0.6 Mpc, 1.3^(+0.8)_(–0.6) × 10^(12) M_☉ within r < 2.9 Mpc, and increases further to M = 3.7^(+1.4)_(–1.1) × 10^(12)M_☉ in the outskirts. The mass of a typical dark matter subhalo that hosts an L* galaxy increases with projected cluster-centric radius in line with expectations from the tidal stripping hypothesis. The mass of a dark matter subhalo that hosts a late-type L^* galaxy is 1.06^(+0.52)_(–0.41) × 10^(12)M_☉. Early-type galaxies appear to be hosted on average in more massive dark matter subhalos compared to late-type galaxies. Early-type galaxies also trace the overall mass distribution of the cluster whereas late-type galaxies are biased tracers. We interpret our findings as evidence for the active assembly of mass via tidal stripping in galaxy clusters. The mass function of dark matter subhalos as a function of projected cluster-centric radius is compared with an equivalent mass function derived from clusters in the Millennium Run simulation populated with galaxies using semianalytic models. The shape of the observationally determined mass functions based on an I-band-selected sample of cluster members and lensing data are in agreement with the shapes of the subhalo mass functions derived from the Millennium Run simulation. However, simulated subhalos appear to be more efficiently stripped than lensing observations suggest. This is likely an artifact of comparison with a dark matter only simulation. Future simulations that simultaneously follow the detailed evolution of the baryonic component during cluster assembly will be needed for a more detailed comparison.
|Additional Information:||© 2009. The American Astronomical Society. Received 2007 November 27; accepted 2008 November 4; published 2009 March 3. Pranjal Trivedi is thanked for help during the early stages of this project. Gabriella De Lucia is gratefully acknowledged for her help in extracting catalogs from the Millennium Simulation, in the analysis of simulated data and thoughtful comments on the draft. Help from Volker Springel is acknowledged for clarifications regarding subhalo extraction from the Millennium Simulation. Some of this work was conducted using support from the grant HST-GO-09722.06-A provided by NASA through a grant from Space Telescope Science Institute,which is operated, by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS5-26555. This paper is based on the observations made with the NASA/ESA Hubble Space Telescope, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. IRS acknowledges support from the Royal Society. ML acknowledges support from the Dark Cosmology Centre funded by the Danish National Research Foundation. The Millennium Simulation databases used in this paper and the web application providing online access to them were constructed as part of the activities of the German Astrophysical Virtual Observatory.|
|Subject Keywords:||dark matter; galaxies: clusters: general; galaxies: halos|
|Official Citation:||The Survival of Dark Matter Halos in the Cluster Cl 0024+16 Priyamvada Natarajan, Jean-Paul Kneib, Ian Smail, Tommaso Treu, Richard Ellis, Sean Moran, Marceau Limousin, and Oliver Czoske 2009 ApJ 693 970-983 doi: 10.1088/0004-637X/693/1/970|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Ruth Sustaita|
|Deposited On:||18 Sep 2009 22:03|
|Last Modified:||26 Dec 2012 11:24|
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