| Popis: |
In this talk is to discuss the relation between the properties of the Galactic Bar and the position of the moving groups in the velocity distribution around the Solar Neighborhood. First, we study the kinematic substructures in the recently released Gaia DR3 data, improving the coverage and accuracy of our previous studies. With these detections, we can compute the gradient of the azimuthal velocity as a function of radius and azimuth for each part of each moving group, showing for the first time this whole new set of observables. Secondly, we study the velocity distribution of different galaxy models using Backwards Integration. This methodology allows us to sweep a dense grid of galaxy models, and determine the properties of the moving groups as a function of the pattern speed of the bar, the slope of the rotation curve, and the position of the disk where the velocity distribution is computed. Finally, we focus on two moving groups that are thought to be caused by resonances of the bar, Hercules and Arch. Two scenarios are compatible with this hypothesis, a fast and a slow bar (i.e. ~40 or ~60 kms^-1 kpc^-1). Although the slow bar is more compatible with independent measurements of the pattern speed, the fast bar produces a velocity distribution more compatible with the stars near the Sun. Using the set of simulations, we study the parameter subspace around both scenarios and demonstrate that a fixed bar pattern speed is not able to reproduce the Gaia large-scale structure for any of the models. |
