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Date and Time of the Query: 2019-04-22 T15:29:53 PDT
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For refcode 2007ApJ...664..123B:
Retrieve 39 NED objects in this reference.
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Copyright by American Astronomical Society. Reproduced by permission
2007ApJ...664..123B The X-Ray Concentration -- Virial Mass Relation David A. Buote, Fabio Gastaldello, Philip J. Humphrey, Luca Zappacosta, James S. Bullock, Fabrizio Brighenti, and William G. Mathews Abstract. We present the concentration (c) -- virial mass (M) relation of 39 galaxy systems ranging in mass from individual early-type galaxies up to the most massive galaxy clusters, (0.06 -- 20)x10^14^ M_sun_. We selected for analysis the most relaxed systems possessing the highest quality data currently available in the Chandra and XMM-Newton public data archives. A power-law model fitted to the X-ray c-M relation requires at high significance (6.6 {sigma}) that c decreases with increasing M, which is a general feature of CDM models. The median and scatter of the c-M relation produced by the flat, concordance {LAMBDA}CDM model ({OMEGA}_m_=0.3, {sigma}_8_=0.9) agrees with the X-ray data, provided that the sample is comprised of the most relaxed, early-forming systems, which is consistent with our selection criteria. When allowing only {sigma}_8_ to vary in the concordance model, the c-M relation requires 0.76<{sigma}_8_<1.07 (99% confidence), assuming a 10% upward bias in the concentrations for early-forming systems. The tilted, low-{sigma}_8_ model suggested by a new WMAP analysis is rejected at 99.99% confidence, but a model with the same tilt and normalization can be reconciled with the X-ray data by increasing the dark energy equation of state parameter to w~-0.8. When imposing the additional constraint of the tight relation between {sigma}_8_ and {OMEGA}_m_ from studies of cluster abundances, the X-ray c-M relation excludes (>99% confidence) both open CDM models and flat CDM models with {OMEGA}_m_~1. This result provides novel evidence for a flat, low-{OMEGA}_m_ universe with dark energy using observations only in the local (z<<1) universe. Possible systematic errors in the X-ray mass measurements of a magnitude ~10% suggested by CDM simulations do not change our conclusions. Key words: Cosmology: Cosmological Parameters, Cosmology: Observations, Cosmology: Dark Matter, X-Rays: Galaxies, X-Rays: Galaxies: Clusters
Retrieve 39 NED objects in this reference.
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