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tokens: radius from the particle data of the N -body simulation. We also determine the circular frequency, Ω, by averaging the radial accelerations of particles in an annulus with a width of 50 pc at each radius. In Fig. 8 , we show Ω + κ/ m ( m =2, 3, 4, and 5) and Ω as functions of R . The horizontal line in Fig. 8 indicates the pattern speed of the bar. The radii at which the line intersects with the frequency curves correspond to the guiding-centre radii for the 2:1, 3:1, 4:1, 5:1, and the corotation resonances. In our model of the MW, the Sun, at a distance of ∼8 kpc from the Galactic Centre, is close to the 3:1 OLR. It is then not surprising that this resonance is dominant in the local stellar population. Figure 8. The orbital frequencies as functions of the galactic radius, R . Ω was determined from the velocity curve and Ω + κ/ m ( m =2, 3, 4, and 5) as expected within the epicycle approximation are plotted. The vertical axis is normalized by Ω 8kpc . The horizontal line indicates the bar’s pattern speed and the vertical lines represent the guiding radii for the respective resonant orbits. 4.2 The MW’s bar pattern speed When projecting the Gaia DR2 data into the R – v φ plane, a series of ridges appear over a wide range of R (Antoja et al. 2018 ; Kawata et al. 2018 ; Ramos et al. 2018 ). Although the origin of these structures is still in debate, previous studies (e.g. Monari et al. 2017b , 2019a ; Fragkoudi et al. 2019 ; Barros et al. 2020 ) have discussed that these ridges may originate from resonances, while other studies have suggested perturbations by a satellite galaxy such as the Sagittarius dwarf (Khanna et al. 2019 ; Laporte et al. 2019 ) or by winding transient spiral structure (Hunt et al. 2018 , 2019 ). In this section, we study the relation between the observed ridges in Gaia DR2 and resonances in our simulated MW model: by projecting our simulated and classified stars into the R – v φ plane, we can directly compare to the same projection of the Gaia DR2 data. If the stars classified by resonance type align with the observed ridges, then this provides compelling evidence that these ridges are indeed caused by resonantly trapped stars. In Fig. 9 , we show the distributions of stars in the R – v φ plane as it arises in our simulated MW model (left-hand column) and in the Gaia DR2 (right-hand column). The top panels show 2D histograms of particles within 2 kpc from the Sun [, in our model]. This panel reveals a selection effect caused by Gaia ’s measurement uncertainties: due to us having selected stars with relative parallax error below 10 per cent the right-hand panel displays systematically fewer stars in approximately concentric rings around the Sun’s position at Visually, this causes the smaller extend of the red area in the right-hand panel. We expected, however, that our analysis is robust with respect to this selection effect: it implies that fewer stars make it into our DR2 projection than into the projection of our