THE X-RAY-SPECTRA OF CLUSTER COOLING FLOWS .1. OPTICALLY THIN MODELS

Optically thin X-ray spectra have been calculated for a set of cluster cooling flow models including homogeneous models and flows with stron g gas loss. We find that models with gas loss have lower total X-ray l uminosities than homogeneous models by a factor of at most 1.35. The i ntegrated surface brightness profiles for models with gas loss are muc h less centrally peaked than the profiles for models with no gas loss. Emergent X-ray spectra from 0.1 to 10 keV are presented for the cooli ng flow as a whole as well as for three apertures centered on the flow . The total X-ray spectra for the various models are quite similar. Fo r spatially resolved spectra, however, the homogeneous models show enh anced soft X-ray line emission in the central regions of the flow as c ompared to the gas-loss models. In the outer regions of the cooling fl ow, the gas-loss models exhibit much more soft X-ray line emission. Su rface brightness profiles, aperture luminosities, and line profiles fo r a set of X-ray lines have also been calculated. For homogeneous mode ls, the profiles for lines produced at low temperatures are very centr ally concentrated, since the majority of the cooling occurs within the sonic radius. In models with gas loss, the cooling is distributed thr oughout the flow region producing a more extended surface brightness p rofile. The line shapes for several strong lines have also been calcul ated. For lines produced at lower temperatures, the homogeneous models produce broad, flat integrated line profiles. The central line shapes in these models are double peaked. For inhomogeneous models and lines produced at higher temperatures, the line shapes are nearly Gaussian. X-ray observations of line profiles such as these could provide direc t evidence that the gas in cluster cooling flows is actually flowing. The feasibility of observations such as these with future X-ray missio ns is discussed.