ASCA and ROSAT observations of distant, massive cooling flows

We present the results from a detailed ASCA/ROSAT X-ray study of threedistant, massive cooling flows; Zwicky 3146 (z=0.291), Abell 1835 (z=0.252) andE1455+223 (Zwicky 7160; z=0.258). Using multiphase models fitted to the ASCAspectra, we determine values for the temperature, metallicity, luminosity andcooling rates in the clusters. These results are combined with deprojectionanalyses of the ROSAT images to provide detailed constraints on the massdistributions in the systems, and on the properties of their cooling flows. Thespectral and imaging data identify these clusters as the three most-massivecooling flows known, with mass deposition rates of ~ 1400, 2300, and 1500 solarmasses per year, respectively. We highlight the need for multiphase models toconsistently model the spectral and imaging X-ray data, and discuss theimportance of using these models in X-ray determinations of the cluster masses.We also present results from an extensive optical study of the clusters andreport the discovery of a gravitational arc in Abell 1835. The lensing dataprovide an indepenent constraint on the distribution of mass in the cluster, ingood agreement with the results from the mutliphase (although not single-phase)X-ray analysis. We present measurements of the galaxy distributions in Abell1835 and E1455+223 and relate these to the distributions of the total mass. TheASCA spectra place firm constraints on the column density of intrinsic X-rayabsorbing material in the clusters. Abell 1835 and E1455+223 exhibit largeintrinsic column densities associated with their cooling flows. These clustersalso exhibit significant amounts of reddening in the optical spectra of theircentral galaxies. The data for Zwicky 3146 indicate lower lower levels of X-rayabsorption and reddening. All three clusters exhibit excellent alignment