2019MNRAS.485.2106M

Models of the Galaxy with analytical Ferrers bars can reproduce the residual velocities of OB associations in the Sagittarius, Perseus and Local System star-gas complexes located within 3 kpc of the solar neighbourhood. Ferrers ellipsoids with a density distribution defined by power indices n = 1 and 2 are considered. The successful reproduction of velocity in the Local System is due to the large velocity dispersion, which weakens resonance effects by producing smaller systematic motions. Model galaxies form nuclear, inner and outer resonance rings R₁ and R₂. The outer rings R₂ manage to catch twice as many particles as rings R₁. The outer Lindblad resonance of the bar (OLR) is located 0.4 kpc beyond the solar circle, at R_OLR = R₀ + 0.4 kpc, corresponding to a bar angular velocity of Ω_b = 50 km s^–1 kpc^–1. The solar position angle with respect to the bar, θ_b, that provides agreement between model and observed velocities is 40-52°. Unfortunately, the models considered cannot reproduce the residual velocities in the Carina and Cygnus star-gas complexes. A redistribution of the specific angular momentum, L, is found near the Lindblad resonances of the bar (inner Lindblad resonance (ILR) and OLR): the average value of L increases (decreases) at radii slightly smaller (larger) than those of the resonances, which could be connected with the existence of two types of periodic orbits elongated perpendicular to each other there.