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Title: The Dark Matter Halos of Massive, Relaxed Galaxy Clusters Observed With Chandra

Abstract

We use the Chandra X-ray Observatory to study the dark matter halos of 34 massive, dynamically relaxed galaxy clusters, spanning the redshift range 0.06 < z < 0.7. The observed dark matter and total mass (dark-plus-luminous matter) profiles can be approximated by the Navarro Frenk & White (hereafter NFW) model for cold dark matter (CDM) halos; for {approx} 80 percent of the clusters, the NFW model provides a statistically acceptable fit. In contrast, the singular isothermal sphere model can, in almost every case, be completely ruled out. We observe a well-defined mass-concentration relation for the clusters with a normalization and intrinsic scatter in good agreement with the predictions from simulations. The slope of the mass-concentration relation, c {infinity} M{sub vir}{sup a}/(1 + z){sup b} with a = -0.41 {+-} 0.11 at 95 percent confidence, is steeper than the value a {approx} -0.1 predicted by CDM simulations for lower mass halos. With the slope a included as a free fit parameter, the redshift evolution of the concentration parameter, b = 0.54 {+-} 0.47 at 95 percent confidence, is also slower than, but marginally consistent with, the same simulations (b {approx} 1). Fixing a {approx} -0.1 leads to an apparent evolution thatmore » is significantly slower, b = 0.20 {+-} 0.45, although the goodness of fit in this case is significantly worse. Using a generalized NFW model, we find the inner dark matter density slope, a, to be consistent with unity at 95 percent confidence for the majority of clusters. Combining the results for all clusters for which the generalized NFW model provides a good description of the data, we measure ? = 0.88 {+-} 0.29 at 95 percent confidence, in agreement with CDM model predictions.« less

Authors:
;
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
893319
Report Number(s):
SLAC-PUB-12150
astro-ph/0610038; TRN: US200625%%605
DOE Contract Number:  
AC02-76SF00515
Resource Type:
Journal Article
Journal Name:
Submitted to Mon.Not.Roy.Astron.Soc.
Additional Journal Information:
Journal Name: Submitted to Mon.Not.Roy.Astron.Soc.
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; GALAXY CLUSTERS; NONLUMINOUS MATTER; ASTRONOMY; Astrophysics,ASTRO

Citation Formats

Schmidt, Robert W, /Heidelberg, Astron. Rechen Inst., Allen, S W, and /KIPAC, Menlo Park. The Dark Matter Halos of Massive, Relaxed Galaxy Clusters Observed With Chandra. United States: N. p., 2006. Web.
Schmidt, Robert W, /Heidelberg, Astron. Rechen Inst., Allen, S W, & /KIPAC, Menlo Park. The Dark Matter Halos of Massive, Relaxed Galaxy Clusters Observed With Chandra. United States.
Schmidt, Robert W, /Heidelberg, Astron. Rechen Inst., Allen, S W, and /KIPAC, Menlo Park. 2006. "The Dark Matter Halos of Massive, Relaxed Galaxy Clusters Observed With Chandra". United States. https://www.osti.gov/servlets/purl/893319.
@article{osti_893319,
title = {The Dark Matter Halos of Massive, Relaxed Galaxy Clusters Observed With Chandra},
author = {Schmidt, Robert W and /Heidelberg, Astron. Rechen Inst. and Allen, S W and /KIPAC, Menlo Park},
abstractNote = {We use the Chandra X-ray Observatory to study the dark matter halos of 34 massive, dynamically relaxed galaxy clusters, spanning the redshift range 0.06 < z < 0.7. The observed dark matter and total mass (dark-plus-luminous matter) profiles can be approximated by the Navarro Frenk & White (hereafter NFW) model for cold dark matter (CDM) halos; for {approx} 80 percent of the clusters, the NFW model provides a statistically acceptable fit. In contrast, the singular isothermal sphere model can, in almost every case, be completely ruled out. We observe a well-defined mass-concentration relation for the clusters with a normalization and intrinsic scatter in good agreement with the predictions from simulations. The slope of the mass-concentration relation, c {infinity} M{sub vir}{sup a}/(1 + z){sup b} with a = -0.41 {+-} 0.11 at 95 percent confidence, is steeper than the value a {approx} -0.1 predicted by CDM simulations for lower mass halos. With the slope a included as a free fit parameter, the redshift evolution of the concentration parameter, b = 0.54 {+-} 0.47 at 95 percent confidence, is also slower than, but marginally consistent with, the same simulations (b {approx} 1). Fixing a {approx} -0.1 leads to an apparent evolution that is significantly slower, b = 0.20 {+-} 0.45, although the goodness of fit in this case is significantly worse. Using a generalized NFW model, we find the inner dark matter density slope, a, to be consistent with unity at 95 percent confidence for the majority of clusters. Combining the results for all clusters for which the generalized NFW model provides a good description of the data, we measure ? = 0.88 {+-} 0.29 at 95 percent confidence, in agreement with CDM model predictions.},
doi = {},
url = {https://www.osti.gov/biblio/893319}, journal = {Submitted to Mon.Not.Roy.Astron.Soc.},
number = ,
volume = ,
place = {United States},
year = {Wed Oct 11 00:00:00 EDT 2006},
month = {Wed Oct 11 00:00:00 EDT 2006}
}