VLT observations of rapid radial velocity variations in roAp stars

We have studied 27 out of the 37 known roAp stars with high resolution spectroscopy using UVES on the ESO VLT. All 27 stars show rapid radial velocity variations with periods similar to those obtained by photometry. Highest pulsation amplitudes are seen for lines of rare earth elements and the Hα core. For some stars other chemical species also have pulsation, but with smaller amplitudes. There are pulsational phase shifts between lines of different rare earth elements. Stars with stronger magnetic fields tend to have lower radial velocity pulsation amplitudes.