SIMBAD references

The kinematics of about 2000 classical Cepheids of the Milky Way with data from Gaia EDR3 catalog has been studied. For some of these stars, there are line-of-sight velocities. On the basis of the nonlinear rotation model, the parameters of the rotation curve of the Galaxy were determined. The circular linear rotation velocity of the near-solar neighborhood around the Galaxy center was V₀ = 236 ± 3 km s^–1 for the assumed Sun's galactocentric distance R₀ = 8.1 ± 0.1 kpc. Analysis of residual velocities of Cepheids based on the linear Ogorodnikov-Milne model showed the presence of the following significantly different from zero gradients: ∂U/∂x, ∂U/∂z, ∂V/∂x, ∂V/∂z and ∂W/∂x, which behave differently depending on the selection radius. The most interesting is the gradient ∂W/∂x ∼ - 0.5 ± 0.1 km s^–1 kpc^–1 (positive rotation of this star system around the Galactic axis y, Ω_y) since the velocities W are free of Galactic rotation. Here we have an indirect influence of various effects leading to a perturbation of the vertical velocities of the Galactic disk stars. Based on a simpler model, a more accurate estimate of this rotation is obtained, Ω_y = 0.51 ± 0.07 km s^–1 kpc^–1.