2005/02/08 by E. De Filippis, M. Sereno, Mark W. Bautz +2 · 12 citations
Mathematics · Physics and Astronomy · #Astrophysics #Atomic physics #Classical mechanics #Cluster (spacecraft) #Cosmology and Gravitation Theories #Galaxies: Formation, Evolution, Phenomena #Galaxy #Galaxy cluster #Geometry #Large sample #Line (geometry) #Line-of-sight #Mathematics #Oblate spheroid #Orientation (vector space) #Physics #Prolate spheroid #Sample (material) #Statistics #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1086/429401
published as Astrophys.J.625:108-120,2005 · 13 pages, 9 figures. Accepted by ApJ
arxiv created 2005/02/08 · openalex publication_date 2005/05/13 · arxiv updated 2011/07/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
We discuss a method to constrain the intrinsic shapes of galaxy clusters by combining X-ray and Sunyaev-Zel'dovich observations. The method is applied to a sample of 25 X-ray-selected clusters, with measured Sunyaev-Zel'dovich temperature decrements. The sample turns out to be slightly biased, with strongly elongated clusters preferentially aligned along the line of sight. This result demonstrates that X-ray-selected cluster samples may be affected by morphological and orientation effects, even if a relatively high threshold signal-to-noise ratio is used to select the sample. A large majority of the clusters in our sample exhibit a marked triaxial structure; the spherical hypothesis is strongly rejected for most sample members. Cooling-flow clusters do not show preferentially regular morphologies. We also show that identification of multiple gravitationally lensed images, together with measurements of the Sunyaev-Zel'dovich effect and X-ray surface brightness, can provide a simultaneous determination of the three-dimensional structure of a cluster, of the Hubble constant, and of the cosmological energy density parameters.