The Integrated Sunyaev-Zeldovich Effect as a Superior Method for Measuring the Mass of Clusters of Galaxies

We investigate empirical scaling relations between the thermalSunyaev-Zeldovich effect (SZE) and cluster mass in simulated clusters ofgalaxies. The simulated clusters have been compiled from four different samplesthat differ only in their assumed baryonic physics. We show that the strengthof the thermal SZE integrated over a significant fraction of the virializedregion of the clusters is relatively insensitive to the detailed heating andcooling processes in the cores of clusters by demonstrating that the derivedscaling relations are nearly identical between the four cluster samplesconsidered. For our synthetic images, the central Comptonization parametershows significant boosting during transient merging events, but the integratedSZE appears to be relatively insensitive to these events. Most importantly, theintegrated SZE closely tracks the underlying cluster mass. Observations throughthe thermal SZE allow a strikingly accurate mass estimation from relativelysimple measurements that do not require either parametric modeling or geometricdeprojection and thus avoid assumptions regarding the physics of the ICM or thesymmetry of the cluster. This result offers significant promise for precisioncosmology using clusters of galaxies.Comment: 4+ pages, 2 figures, accepted to ApJ Letters; minor changes to text, added reference