BD-21 1873 , the SIMBAD biblio

We present rotation curves of the Galaxy based on the space-velocities of 197 OB stars and 144 classical cepheids, respectively, which range over a galactocentric distance interval of about 6 to 12kpc. No significant differences between these rotation curves and rotation curves based solely on radial velocities assuming circular rotation are found. We derive an angular velocity of the LSR of {OMEGA}₀=5.5±0.4mas/a (OB stars) and {OMEGA}₀=5.4±0.5mas/a (cepheids), which is in agreement with the IAU 1985 value of {OMEGA}₀=5.5mas/a. If we correct for probable rotations of the FK5 system, the corresponding angular velocities are {OMEGA}₀=6.0mas/a (OB stars) and {OMEGA}₀=6.2mas/a (cepheids). These values agree better with the value of {OMEGA}₀=6.4mas/a derived from the VLA measurement of the proper motion of SgrA^*.