Comparison between predictions of the density-wave theory and observational data

Abstract

We present a compilation of spiral tracers with distance and radial velocity data that includes OB stars, supergiants and long period cepheids, in the region 260° < l < 340° and -5°< b < 5°. We obtain observed radial velocity residuals for those stars as the difference between the radial velocity relative to the LSR and the radial velocity calculated from a model of galactic rotation. The observed residuals are compared to the theoretical residuals that are obtained from the prediction of the density-wave theory (the Lind and Shu theory). We find coincidences in some particular region but, considering the overall picture, there is no significant agreement between theory and observation.