Distribution of stars by rotational velocities from spectral data

The rotating velocity of stars is a significant parameter for the stellar formation and evolution study. From spectroscopic observations, we can obtain parameter v sin i, whereas the inclination i itself can be derived only for a small number of stars. The distribution of the stellar rotation rates is poorly understood, which makes this topic of particular interest. We used data from major spectroscopic missions APOGEE and GALAH, together with Glebocki catalogue, to obtain v sin i for a variety of main-sequence stars. This observational data were fitted with a power law, and we provide approximation formulas for stellar 
distribution by rotational velocities.