New parametrizations of non-Gaussian line-of-sight velocity distribution

A five-parameter fitting formula for the line-of-sight stellar velocity distributions (LOSVDs) of steady-state systems is proposed. It can faithfully reproduce velocity distributions of theoretical models ranging from nearly Gaussian profiles to strongly skewed or mildly double-peaked profiles. In contrast to the assumptions of van der Marel & Franx and Kuijken & Merrifield, the LOSVDs are required to have neither multipeaks nor negative velocity wings and most information can be recovered from no more than five physically meaningful fitting parameters.