Cite Ortwin?

[gusbeane]

Ortwin Gerhard just gave a talk on the bar in the Milky Way.  He
claims there is evidence that the bar is ~ 7 Gyrs old.  I imagine
this would be in conflict with the fast bar pattern speed ( ~ 39 km/sec/kpc)
if the bar is interacting with only the halo and no gas.

I don't completely understand the evidence he was claiming, but
he said: "Metal rich stars seen by APOGEE in the outer bar
region are on resonant orbits and form a radially thick, metal-rich
inner ring of peak age ~ 7 Gyrs.  Similar barred galaxies in Auriga
simulations imply. bar age ~ 7 Gyrs."