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Session 53 - The X Clusters: Cooling Flows.
Display session, Thursday, January 08
Exhibit Hall,

[53.01] Scaling Laws and the Mass Function of Galaxy Clusters

D. Horner (UMD/GSFC), R. Mushotzky, M. Loewenstein (NASA/GSFC), C. Scharf (STScI)

The mass function of galaxy clusters and groups provides a direct test of cosmological theories of structure formation and strongly constrains the value of Ømega_0, but currently the mass function is poorly determined. First, there are few large statistical samples of clusters, especially at low masses (i.e. poor clusters and groups). Second, few clusters have reliably determined masses since current mass estimation techniques are difficult to apply. However, recent theoretical progress has been made on the relation of galaxy cluster mass to average x-ray temperature. Combined with improvements in the empirically derived relation between x-ray luminosity and average x-ray temperature, a robust scaling of cluster mass to x-ray luminosity can now be obtained. We apply this relation to new x-ray selected samples of clusters available from ROSAT observations to better determine the mass function over several orders of magnitude in mass, from rich clusters to groups.

Program listing for Thursday