Kinematics of the galaxy from Cepheids with proper motions from the Gaia DR1 catalogue

Abstract

A sample of classical Cepheids with known distances and line-of-sight velocities has been supplemented with proper motions from the Gaia DR1 catalogue. Based on the velocities of 260 stars, we have found the components of the peculiar solar velocity vector (U, V, W)_⊙ = (7.90, 11.73, 7.39) ± (0.65, 0.77, 0.62) km s⁻¹ and the following parameters of the Galactic rotation curve: Ω₀ = 28.84 ± 0.33 km s⁻¹ kpc⁻¹, Ω′₀ = −4.05 ± 0.10 km s⁻¹ kpc⁻², and Ω″₀ = 0.805 ± 0.067 km s⁻¹ kpc⁻³ for the adopted solar Galactocentric distance R₀ = 8 kpc; the linear rotation velocity of the local standard of rest is V₀ = 231 ± 6 km s⁻¹.