$\star$ Galactic absorption according to the morphology of the galaxy

The elliptic galaxies are galaxies older than the galaxies elliptic and irregular, the rates of star formation are much less significant and the clouds of dust which were the incubators before are condensed. The luminosity of the objects contained in this galaxy will on average undergo less absorption.

In particular, the supernovæ contained in the elliptic galaxies will undergo less absorption than their homonym in the spiral galaxies. The comparison of two batches of supernovæ having exploded respectively in spiral and elliptic galaxies allows in theory a study of their absorption in their galaxy host.