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Cosmological constraints from Chandra observations of galaxy clusters.
Allen, Steven W.
Afiliação
  • Allen SW; Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 0HA, UK.
Philos Trans A Math Phys Eng Sci ; 360(1798): 2005-17, 2002 Sep 15.
Article em En | MEDLINE | ID: mdl-12804243
ABSTRACT
Chandra observations of rich, relaxed galaxy clusters allow the properties of the X-ray gas and the total gravitating mass to be determined precisely. Here, we present results for a sample of the most X-ray luminous, dynamically relaxed clusters known. We show that the Chandra data and independent gravitational lensing studies provide consistent answers on the mass distributions in the clusters. The mass profiles exhibit a form in good agreement with the predictions from numerical simulations. Combining Chandra results on the X-ray gas mass fractions in the clusters with independent measurements of the Hubble constant and the mean baryonic matter density in the Universe, we obtain a tight constraint on the mean total matter density of the Universe, Omega(m), and an interesting constraint on the cosmological constant, Omega(Lambda). We also describe the 'virial relations' linking the masses, X-ray temperatures and luminosities of galaxy clusters. These relations provide a key step in linking the observed number density and spatial distribution of clusters to the predictions from cosmological models. The Chandra data confirm the presence of a systematic offset of ca. 40% between the normalization of the observed mass-temperature relation and the predictions from standard simulations. This finding leads to a significant revision of the best-fit value of sigma(8) inferred from the observed temperature and luminosity functions of clusters.
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Base de dados: MEDLINE Tipo de estudo: Prognostic_studies Idioma: En Revista: Philos Trans A Math Phys Eng Sci Assunto da revista: BIOFISICA / ENGENHARIA BIOMEDICA Ano de publicação: 2002 Tipo de documento: Article País de afiliação: Reino Unido
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Base de dados: MEDLINE Tipo de estudo: Prognostic_studies Idioma: En Revista: Philos Trans A Math Phys Eng Sci Assunto da revista: BIOFISICA / ENGENHARIA BIOMEDICA Ano de publicação: 2002 Tipo de documento: Article País de afiliação: Reino Unido