New Parametrizations of Non-Gaussian Line-of-sight Velocity Distribution

A five-parameter fitting formula for the line-of-sight stellar velocity distributions 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 van der Marel and Franx (1993) and Kuijken and Merrifield (1993), the line profiles are required to have neither multi-peaks nor negative velocity wings. Information of the profile is mostly specified by five physically meaningful and nearly orthogonal fitting parameters.