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We investigate the kinematics of stars in the mid-plane of the Milky Way on scales between 25 pc and 10 kpc with data from the Apache Point Observatory Galactic Evolution Experiment (APOGEE), the Radial Velocity Experiment (RAVE), and the Geneva-Copenhagen Survey (GCS). Using red-clump stars in APOGEE, we determine the large-scale line-of-sight velocity field out to 5 kpc from the Sun in (0. 75 kpc) ² bins. The solar motion Vₒₔ₍-₂ with respect to the circular velocity Vc is the largest contribution to the power on large scales after subtracting an axisymmetric rotation field; we determine the solar motion by minimizing the large-scale power to be Vₒₔ₍-₂ = 24+/-1 (ran. ) +/-2 (syst Vc) +/-5 (syst. large-scale) km/s, where the systematic uncertainty is due to (a) a conservative 20 km/s uncertainty in Vc and (b) the estimated power on unobserved larger scales. Combining the APOGEE peculiar-velocity field with red-clump stars in RAVE out to 2 kpc from the Sun and with local GCS stars, we determine the power spectrum of residual velocity fluctuations in the Milky Way's disk on scales between 0. 2/kpc ~3 kpc scales in the Milky Way are in good agreement with observations of external galaxies and directly explain why local determinations of the solar motion are inconsistent with global measurements.
Bovy et al. (Wed,) studied this question.