SIMBAD references

We analyse a sample of 507 evolved (OH/IR) stars in the region (10°>ℓ>-45°), ({verbar}b{verbar}<3°). We derive average ages for subsets of this sample, and use those sets as beacons for the evolution of the Galaxy. In the bulge, the oldest OH/IR stars in the plane are 7.5Gyr (1.3M_☉), and in the disc 2.7Gyr (2.3M_☉). The vertical distribution of almost all AGB stars in the disc is found to be nearly exponential, with scaleheight increasing from 100pc for stars ≲1Gyr old to 500pc for stars ≳5Gyr old. There may be a small, disjunct population of OH/IR stars. The radial distribution of AGB stars is dictated by the metallicity gradient. Unequivocal morphological evidence is presented for the existence of a central bar, but parameters can be constrained only for a given spatial-density model. Using a variety of indicators, we identify the radii of the inner ultraharmonic (2.5kpc) and corotation resonance (3.5kpc). We show that the 3-kpc arm is likely to be an inner ring, as observed in other barred galaxies, by identifying a group of evolved stars that is connected to the 3-kpc Hi filament. Also, using several observed features, we argue that an inner-Lindblad resonance exists, at ∼1-1.5kpc. The compositions of OH/IR populations within 1kpc of the Galactic Centre give insight into the bar-driven evolution of the inner regions. We suggest that the bar is ∼8Gyr old, relatively weak (SAB), and may be in a final stage of its existence.