Clusters of galaxies
Date: 06 December 2000
Top left: X-ray image for Abell S 1101(=Sirsic 159-03) obtained by XMM-Newton's European Photon Imaging Camera (EPIC-MOS). Analysis has shown a sharp temperature drop near the outer part of the cluster, which might be associated with the transition from cluster to supercluster. Courtesy J. Kaastra, SRON, Utrecht, NL.
Middle right: Past studies have implied the presence of cool gas near the centers of clusters of galaxies. This, and other, characteristics have been studied in the Abell 1835 cluster of galaxies using the EPIC and RGS instruments on XMM-Newton. Observations have allowed the measurement of both the relative X-ray emission of the cold gas and a detailed study of the spectral properties of total gas distribution. The traditional model for cooling flows is not compatible with these observations, and new models will have to be sought. Courtesy J. Peterson, Columbia Univ., NY, USA.
Bottom left: XMM-Newton has observed the Abell 1795 cluster, one of the best targets for XMM-Newton to study the center of a cluster of galaxies. Its large-scale properties were measured with the EPIC spatially-resolved spectra and the high resolution Reflection Grating Spectrometers (RGS) were used to constrain the temperature structure of the cluster core. Courtesy T. Tamura, SRON, Utrecht, NL.
