Buckling bars in nearly face-on galaxies observed with MaNGA
  Over half of disk galaxies are barred, yet the mechanisms for bar formation
and the life-time of bar buckling remain poorly understood. In simulations, a
thin bar undergoes a rapid (<1 Gyr) event called "buckling," during which the
inner part of the bar is asymmetrically bent out of the galaxy plane and
eventually thickens, developing a peanut/X-shaped profile when viewed side-on.
Through analyzing stellar kinematics of N-body model snapshots of a galaxy
before, during, and after the buckling phase, we confirm a distinct quadrupolar
pattern of out-of-plane stellar velocities in nearly face-on galaxies. This
kinematic signature of buckling allows us to identify five candidates of
currently buckling bars among 434 barred galaxies in the Mapping Nearby
Galaxies at Apache Point Observatory (MaNGA) Survey, an integral field unit
(IFU) spectroscopic survey that measures the composition and kinematic
structure of nearby galaxies. The frequency of buckling events detected is
consistent with the 0.5-1 Gyr timescale predicted by simulations. The five
candidates we present more than double the total number of candidate buckling
bars, and are the only ones found using the kinematic signature.
