The Milky Way satellites offer the possibility of studying their star formation histories in great detail. Color-magnitude diagrams (CMDs) reaching the old main-sequence turnoffs, allow a careful modelling of their stellar populations using synthetic CMDs, and spectroscopy of the brightest stars, provides a direct measurement of their metallicity

We have analyzed the shape of III Zw2 Hα emission line observed at Isaac Newton telescope. A model with a Keplerian relativistic disk plus one emission region more very well fit the line profile. Disk emission contribute the line wings, while the line core is probably originated in a region which surrounds the disk.

We study the origin of the colour magnitude relation (CMR) in the Virgo cluster. The CMR could be either caused by a variation of the mean stellar metallicity along the sequence (Kodama and Arimoto, 1997) or by a combination of age and metallicity variations (Ferreras, Charlot and Silk, 1999). This uncertainty is due to the fact that the integrated

We studied a moderate-redshift (0.15 5 orders of magnitude in nuclear power, and the two sub-samples have indistinguishable luminosity--redshift distributions over the redshift range 0.15 z 0.5. No correlation between nuclear brightness (corrected for beaming) and galaxy luminosity is seen. Assuming the host galaxy--black hole mass correlation

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