Magnesium-to-Iron Ratio in Nuclei and Bulges of Disk Galaxies

The results of magnesium-to-iron ratio estimates are presented for the nuclei and central bulges of disk galaxies. A great variety of behaviours is found: the nuclei have solar Mg/Fe ratio or are Mg-overabundant, the bulges can be more or less Mg-overabundant than the nuclei. But the most bulges have nearly solar Mg/Fe ratios, irrespective of their luminosity. This revised version was published online in July 2006 with corrections to the Cover Date.