Chemodynamical signatures of bar resonances in the Galactic disk:
  current data and future prospects
  The Galactic disk exhibits complex chemical and dynamical substructure
thought to be induced by the 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 homogeneous 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 that associates the "hat" moving group with its outer Lindblad
resonance and "Hercules" 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 chemodynamical 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.
