High-resolution X-ray spectroscopic constraints on cooling-flow models for clusters of galaxies

We present high-resolution X-ray spectra of 14 putative cooling-flow clusters of galaxies obtained with the Reflection Grating Spectrometer on XMM-Newton. The clusters in the sample span a large range of temperatures and mass deposition rates. Various of these spectra exhibit line emission from O VIII, Ne X, Mg XII and XI, Al XIII and XII, Si XIV and XIII, N VII, and C VI as well as all Fe L ions. The spectra exhibit strong emission from cool plasma at just below the ambient temperature, T-0, down to T-0/2, but also exhibit a severe deficit of emission relative to the predictions of the isobaric cooling-flow model at lower temperatures (