Mass Models and Sunyaev-zeldovich Effect Predictions for a Flux-limited Sample of 22 Nearby X-ray Clusters

We deÐne a 90% complete, volume-limited sample of 31 z\ 0.1 X-ray clusters and present a systematic analysis of public ROSAT PSPC data on 22 of these objects. Our e†orts are undertaken in support of the Penn/OVRO Sunyaev-Zeldovich E†ect (SZE) survey, and to this end we present predictions for the inverse Compton optical depth toward all 22 of these clusters. We have performed detailed Monte Carlo simulations in order to understand the e†ects of the cluster proÐle uncertainties on the SZE predictions given the OVRO 5.5 m telescope beam and switching patterns. We also present a similar analysis for the upcoming ACBAR experiment. For most of the clusters in the sample, we Ðnd less than a 5% uncertainty in the SZE predictions due to an imperfect knowledge of the proÐle. A comparison of di†erent cooling-Ñow modeling strategies shows that our results are robust in this respect. The proÐle uncertainties are then one of the least signiÐcant components of our error budget for SZE-based distance measurements. The density models that result from this analysis also yield baryonic masses and, under the assumption of hydrostatic equilibrium, total masses and baryon mass fractions. Our Monte Carlo proÐle analysis indicates that the baryon masses within 1 Mpc for these clusters are accurate to h100 ~1 better than D5% and una†ected by realistic PSPC systematics. In the sample as a whole, we Ðnd a mean gas mass fraction of internal to Mpc. This is in agreement (7.02^ 0.28)h100 ~3@2 ] 10~2 R500D 1 h100 ~1 with previous X-ray cluster analyses, which indicate an overabundance of baryons relative to the prediction of big bang nucleosynthesis for an universe. Our analysis of the X-ray spectra conÐrms a ) M \ 1 previous claim of an excess absorbing column density toward A478, but we do not Ðnd evidence for anomalous column densities in the other 21 clusters. We also Ðnd some indications of an excess of soft counts in the ROSAT PSPC data. A measurement of using these models and OVRO SZE determiH0 nations will be presented in a second paper. Subject headings : distance scale È galaxies : clusters : general È large-scale structure of universe È X-rays : galaxies