Planetary nebulae and the galactic rotation curve.

The authors have used radial velocities of planetary nebulae from their recently completed catalog to derive the galactic rotation curve beyond the solar circle. The results show a rising rotation curve out to at least 15 kpc from the galactic center, in agreement with results for younger galactic objects. Conversely, from the established rotation curve within the solar circle, it is found that Acker's distance scale for the planetary nebulae should be increased by a factor of 1.4×(R₀/8.5 kpc).