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Session 52 - Clusters & Cosmology.
Oral session, Thursday, June 12
North Main Hall C/D,

[52.02] 1E0657-56: A Contender for the Hottest Known Cluster

W. Tucker, P. Blanco, S. Rappoport (UCSD), L. David, D. Fabricant, E. Falco, W. Forman, M. Ramella (Harvard-Smithsonian CfA), A. Dressler (Carnegie Obs.)

We report here on X-ray and optical observations of a newly discovered cluster of galaxies, 1E 0657-56. Optical observations of an unidentified, extended Einstein X-ray source revealed the presence of a cluster of galaxies with a redshift z = 0.30, and a background gravitational arc at an undetermined redshift. X-ray data obtained with the ROSAT HRI and ASCA suggest that 1E 0657-56 is a highly luminous cluster in which a merger of subclusters is occurring. The temperature of the hot gas in 1E0657 is 14 keV, which places it in a select class of two with the cluster A2163 (Arnaud et al. 1992). As emphasized by Arnaud et al (1992) and Hattori (1994), the existence of one or more clusters with a gas temperature in excess of 10 keV has important implications for the cosmological theory of origin of clusters of galaxies, because large initial density fluctuations are required.

Program listing for Thursday