Chemodynamical signatures of bar resonances in the Galactic disk: current data and future prospects

Abstract

The Galactic disk exhibits complex chemical and dynamical substructure thought to be induced by the bar, spiral arms, and satellites. Here, we explore the chemical signatures of bar resonances in action and velocity space and characterize the differences between the signatures of corotation and higher-order resonances using test particle simulations. Thanks to recent surveys, we now have large datasets containing metallicities and kinematics of stars outside the solar neighborhood. We compare the simulations to the observational data from Gaia EDR3 and LAMOST DR5 and find weak evidence for a slow bar with the "hat" moving group ($250\text{km/s}\lesssim v_{\varphi }\lesssim 270\text{km/s}$) associated with its outer Lindblad resonance and "Hercules" ($170\text{km/s}\lesssim v_{\varphi }\lesssim 195\text{km/s}$) with corotation. While constraints from current data are limited by their spatial footprint, stars closer in azimuth than the Sun to the bar's minor axis show much stronger signatures of the bar's outer Lindblad and corotation resonances in test particle simulations. Future datasets with greater azimuthal coverage, including the final Gaia data release, will allow reliable chemodynamical identification of bar resonances.

Published in ApJ

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Cited by in corpus (10)

• Mapping the Galactic Metallicity Gradient with Open Clusters: The State-of-the-Art and Future Challenges
• Stellar halo substructure generated by bar resonances
• Chemical Cartography with LAMOST and Gaia Reveal Azimuthal and Spiral Structure in the Galactic Disk
• Radial halo substructure in harmony with the Galactic bar
• Timing the Milky Way bar formation and the accompanying radial migration episode
• The Non-Axisymmetric Influence: Radius and Angle-Dependent Trends in a Barred Galaxy
• Trojan globular clusters: radial migration via trapping in bar resonances
• Dynamical streams in the local stellar halo
• Gas Transfer Between the Inner 3-kpc Disk and the Galactic Central Molecular Zone
• Moving Groups in the Solar Neighborhood with Gaia, APOGEE, GALAH, and LAMOST: Dynamical Effects Gather Gas and the Ensuing Star Formation Plays an Important Role in Shaping the Stellar Velocity Distributions