Accuracy Diagrams for the Galactic Rotation Curve and Kinematical Distances

Abstract

We revisit the methods to determine the Galactic rotation curve and kinematical distances from radial velocities and proper motions. We construct "accuracy diagrams" to show the distributions in the galactic plane of expected uncertainties in the derived quantities such as rotation velocities and kinematical distances. We discuss how to optimize the source selection for measurements of kinematical quantities based on the accuracy diagrams.