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 (2 = 0.252) and E 1455 + 223 (Zwicky 7160; z = 0,258). Using multiphase models fitted to the ASCA spectra, we determine values for the temperature, metallicity, luminosity and cooling rates in the clusters. These results are combined with deprojection analyses of the ROSAT images to provide detailed constraints on the mass distributions in the systems, and on the properties of their cooling flows. The spectral and imaging data identify these clusters as three of the most massive cooling flows known, with mass deposition rates of ∼1400, 2300 and 1500 M_⊙ yr^-1 respectively. We highlight the need for multiphase models to model consistently the spectral and imaging X-ray data, and discuss the importance of using these models in X-ray determinations of the cluster masses. We also present results from an extensive optical study of the clusters and discuss the implications of new results on gravitational lensing in Abell 1835, presented more fully in a forthcoming companion paper by Edge et al. The lensing data provide an independent constraint on the distribution of mass in the cluster, in good agreement with the results from the multiphase (though not single-phase) X-ray analysis. We present measurements of the galaxy distributions in Abell 1835 and E 1455 + 223, and relate these to the distributions of the total mass. The ASCA spectra place firm constraints on the column density of intrinsic X-ray-absorbing material in the clusters. Abell 1835 and E 1455 + 223 exhibit large intrinsic column densities [N_H∼(3-4) × 10²¹ atom cm^-2] associated with their cooling flows. These clusters also exhibit significant amounts of reddening in the optical spectra of their central galaxies. The data for Zwicky 3146 indicate lower levels of X-ray absorption and reddening. All three clusters exhibit excellent alignment between the position angles of their X-ray emission and the optical emission from their dominant cluster galaxies.