We are attempting to learn the circumstances under which bursts of star formation may be triggered around the nuclei of many nearby spiral galaxies. By comparing the observed equivalent widths of the Brγ emission line and the CO(2-0) absorption band in each of the circumnuclear hotspots, with starburst models from the literature, we can place

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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