ASCA AND ROSAT OBSERVATIONS OF DISTANT, MASSIVE COOLING FLOWS

We present the results from a detailed ASCA/ROSAT X-ray study of three distant, massive cooling flows: Zwicky 3146 (z=0.291), Abell 1835 (z= 0.252) and E 1455 + 223 (Zwicky 7160; z=0.258). Using multiphase model s fitted to the ASCA spectra, we determine values for the temperature, metallicity, luminosity and cooling rates in the clusters. These resu lts are combined with deprojection analyses of the ROSAT images to pro vide detailed constraints on the mass distributions in the systems, an d on the properties of their cooling Rows. The spectral and imaging da ta identify these clusters as three of the most massive cooling flows known, with mass deposition rates of similar to 1400, 2300 and 1500 M. yr(-1) respectively, We highlight the need for multiphase models to m odel consistently the spectral and imaging X-ray data, and discuss the importance of using these models in X-ray determinations of the clust er masses. We also present results from an extensive optical study of the clusters and discuss the implications of new- results on gravitati onal lensing in Abell 1835, presented more fully in a forthcoming comp anion paper by Edge et al. The lensing data provide an independent con straint on the distribution of mass in the cluster, in good agreement with the results from the multiphase (though not single-phase) X-ray a nalysis, We present measurements of the galaxy distributions in Abell 1835 and E 1455 + 223, and relate these to the distributions of the to tal mass. The ASCA spectra place firm constraints on the column densit y of intrinsic X-ray-absorbing material in the clusters, Abell 1835 an d E 1455 + 223 exhibit large intrinsic column densities [N-H similar t o (3 - 4) x 10(21) atom cm(-2)] associated with their cooling flows. T hese clusters also exhibit significant amounts of reddening in the opt ical spectra of their central galaxies. The data for Zwicky 3146 indic ate lower levels of X-ray absorption and reddening. All three clusters exhibit excellent alignment between the position angles of their X-ra y emission and the optical emission from their dominant cluster galaxi es.