No direct coupling between bending of galaxy disc stellar age and light
  profiles
  We study the stellar properties of 44 face-on spiral galaxies from the Calar
Alto Legacy Integral Field Area survey via full spectrum fitting techniques. We
compare the age profiles with the surface brightness distribution in order to
highlight differences between profile types (type I, exponential profile; and
II, down-bending profile). We observe an upturn ("U-shape") in the age profiles
for 17 out of these 44 galaxies with reliable stellar information up to their
outer parts. This "U-shape" is not a unique feature for type II galaxies but
can be observed in type I as well. These findings suggest that the mechanisms
shaping the surface brightness and stellar population distributions are not
directly coupled. This upturn in age is only observable in the light-weighted
profiles while it flattens out in the mass-weighted profiles. Given recent
results on the outer parts of nearby systems and the results presented in this
Letter, one of the most plausible explanations for the age upturn is an early
formation of the entire disc ($\sim$~10~Gyr ago) followed by an inside-out
quenching of the star formation.
