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D.J. Horner, M. Donahue, M. Voit (Space Telescope Science Institute)
Entropy is a more fundamental parameter in clusters of galaxies than temperature or density because convection acts as an entropy sorting device, moving low entropy material to the cluster core and high entropy material to the outskirts. Thus the entropy profile in a cluster determines the density and temperature profiles. Because cluster properties do not conform to self-similar scaling relations, some combination of radiative cooling, supernova feedback, and AGN feedback must have modified the entropy distributions of clusters at an early time. In order to identify the physical effects that caused this similarity breaking, we have begun a project to construct a library of entropy distributions derived from Chandra cluster data. These entropy distributions will provide an ideal testbed for evaluating theories of how radiative cooling and energy injection determine the properties of present-day clusters. Here we present initial results of the project.
Bulletin of the American Astronomical Society,
© 2003. The American Astronomical Soceity.