High Resolution Spectroscopy of 14 Cooling-Flow Clusters of Galaxies Using the Reflection Grating Spectrometers on XMM-Newton

Abstract

We present high resolution X-ray spectra of 14 cooling-flow X-ray clusters and groups obtained with the Reflection Grating Spectrometers (RGS) on XMM-Newton. The spectra exhibit line emission from a number of Fe L charge states as well as O VIII, Mg XII, Ne X, Si XIV & XIII, N VII, and C VI. All spectra show a deficit of soft X-ray lines predicted from the isobaric multi-phase spectral model as compared with morphological mass deposition rates from spatially-resolved spectroscopy with the European Photon Imaging Cameras (EPIC). We present some weak detections of plasma several times cooler than the ambient cluster temperatures. The results further suggest that either morphological mass deposition rates systematically overestimate the actual cooling rate or the emission measure of cooling-flows has a much steeper distribution than that predicted by a simple isobaric multi-phase model. We briefly discuss some modifications to the cooling-flow process.