Velocity width measurements of the coolest X-ray emitting material in
  the cores of clusters, groups and elliptical galaxies
  We examine the velocity width of cool X-ray emitting material using
XMM-Newton Reflection Grating Spectrometer (RGS) spectra of a sample of
clusters and group of galaxies and elliptical galaxies. Improving on our
previous analyses, we apply a spectral model which accounts for broadening due
to the spatial extent of the source. With both conventional and Markov Chain
Monte Carlo approaches we obtain limits, or in a few cases measurements, of the
velocity broadening of the coolest X-ray material. In our sample, we include
new observations targeting objects with compact, bright, line-rich cores. One
of these, MACSJ2229.7-2755, gives a velocity limit of 280 km/s at the 90 per
cent confidence level. Other systems with limits close to 300 km/s include
A1835, NGC4261 and NGC4472. For more than a third of the targets we find limits
better than 500 km/s. HCG62, NGC1399 and A3112 show evidence for ~400 km/s
velocity broadening. For a smaller sample of objects, we use
continuum-subtracted emission line surface brightness profiles to account for
the spatial broadening. Although there are significant systematic errors
associated with the technique (~150 km/s), we find broadening at the level of
280 to 500 km/s in A3112, NGC1399 and NGC4636.
