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The Contribution of Halos with Different Mass Ratios to the Overall Growth of Cluster-sized Halos

Lemze, Doron and Newman, Andrew B. (2013) The Contribution of Halos with Different Mass Ratios to the Overall Growth of Cluster-sized Halos. Astrophysical Journal, 776 (2). Art. No. 91. ISSN 0004-637X. doi:10.1088/0004-637X/776/2/91.

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We provide a new observational test for a key prediction of the ΛCDM cosmological model: the contributions of mergers with different halo-to-main-cluster mass ratios to cluster-sized halo growth. We perform this test by dynamically analyzing 7 galaxy clusters, spanning the redshift range 0.13 < z_c < 0.45 and caustic mass range 0.4-1.5 10^(15)h_(0.73)^(-1) M_☉, with an average of 293 spectroscopically confirmed bound galaxies to each cluster. The large radial coverage (a few virial radii), which covers the whole infall region, with a high number of spectroscopically identified galaxies enables this new study. For each cluster, we identify bound galaxies. Out of these galaxies, we identify infalling and accreted halos and estimate their masses and their dynamical states. Using the estimated masses, we derive the contribution of different mass ratios to cluster-sized halo growth. For mass ratios between ~0.2 and ~0.7, we find a ~1σ agreement with ΛCDM expectations based on the Millennium simulations I and II. At low mass ratios, ≾ 0.2, our derived contribution is underestimated since the detection efficiency decreases at low masses, ~2 × 10^(14) h_(0.73)^(-1) M_☉. At large mass ratios, ≳ 0.7, we do not detect halos probably because our sample, which was chosen to be quite X-ray relaxed, is biased against large mass ratios. Therefore, at large mass ratios, the derived contribution is also underestimated.

Item Type:Article
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URLURL TypeDescription Paper
Newman, Andrew B.0000-0001-7769-8660
Additional Information:© 2013 American Astronomical Society. Received 2013 March 20; accepted 2013 August 3; published 2013 October 3. We thank Margaret J. Geller, Kenneth Rines, Michael Kurtz, and Antonaldo Diaferio for providing their redshift data for A611 and CL2130 and for providing the redshift data for A963, A2261, A1423, and RXJ2129 in advance of publication. We also thank them for many helpful discussions. In addition, we acknowledge very useful discussions with Ana Laura Serra, Dan Gifford, Mark Neyrinck, Yuval Birnboim, Eyal Neistein, and Maxim Markevitch. We thank the anonymous referee for useful comments. D.L. thanks Eran Ofek for his publicly available Matlab scripts. This research is supported in part by NASA grant HST-GO-12065.01-A. M.M. acknowledges support from PRIN INAF 2009 and ASI (agreement Euclid phase B2/C). A.Z. is supported by contract research “Internationale Spitzenforschung II/2-6” of the Baden Württemberg Stiftung.
Funding AgencyGrant Number
ASI Euclid PhaseB2/C
Baden Württemberg Stiftung Internationale SpitzenforschungII/2-6
Subject Keywords: dark matter; galaxies: clusters: individual (Abell 611, Abell 963, Abell 1423, Abell 2261, MACS J1206.2–0848, RX J2129.7+0005, CL 2130.4–0000); galaxies: kinematics and dynamics
Issue or Number:2
Record Number:CaltechAUTHORS:20131223-095144403
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Official Citation:The Contribution of Halos with Different Mass Ratios to the Overall Growth of Cluster-sized Halos Doron Lemze et al. 2013 ApJ 776 91
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:43137
Deposited By: Ruth Sustaita
Deposited On:23 Dec 2013 18:21
Last Modified:10 Nov 2021 16:33

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