Self-similarity in the chemical evolution of galaxies and the delay time
  distribution of SNe Ia
  Recent improvements in the age dating of stellar populations and single stars
allow us to study the ages and abundance of stars and galaxies with
unprecedented accuracy. We here compare the relation between age and
\alpha-element abundances for stars in the solar neighborhood to that of local,
early-type galaxies. We find both relations to be very similar. Both fall into
two regimes with a flat slope for ages younger than ~9 Gyr and a steeper slope
for ages older than that value. This quantitative similarity seems surprising,
given the different types of galaxies and scales involved. For the sample of
early-type galaxies we also show that the data are inconsistent with literature
delay time distributions of either single or double Gaussian shape. The data
are consistent with a power law delay time distribution. We thus confirm that
the delay time distribution inferred for the Milky Way from chemical evolution
arguments also must apply to massive early-type galaxies. We also offer a
tentative explanation for the seeming universality of the age-[\alpha/Fe]
relation as the manifestation of averaging of different stellar populations
with varying chemical evolution histories.
