Properties of cooling flows in a flux-limited sample of clusters of galaxies

An analysis of the mass flow rates of cooling flows in an X-ray flux-limited sample of clusters of galaxies, in which most of the clusters have been observed with both imaging and spectroscopic detectors, is presented. Using high-quality images and constraints from broad-band spectra, it is found that the fraction of clusters with central cooling times less than the Hubble time is high (at least 70 per cent and possibly 90 per cent), indicating that cooling flows are a common and long-lived phenomenon. The fraction is higher than found in previous studies, due to our consideration of the effects of the spatial resolution and the signal-to-noise ratio of the images