Dwarf galaxies may play a key role in the formation and evolution of bigger systems. This makes it a topic of major interest to know how they form and evolve and, in particular, how their star formation histories (SFHs) have proceeded since their birth. For nearby galaxies, the colour-magnitude diagram (CMD) contains stars formed over their full

We consider the branching ratio for the process $t o c gamma$ in the context of the General Two Higgs Doublet Model type III. We find that taking into account reasonable values for the parameter $ an eta$ is possible to get values of this branching ratio up to orders of magnitude lying in the range of sensitivity of near future top quark

Using high-quality H_α images of five spiral galaxies, we have studied the luminosity and distribution of the emission from diffuse ionized gas (DIG). The estimated DIG luminosities account for 25-60% of the total H_α emission in each galaxy and analysis of the distribution has shown that the DIG is highly correlated geometrically with the most

High resolution observations of interstellar Na I absorptions in the spectra of early-type stars in the second Galactic quadrant have been used to derive the spatial distribution of the nearby interstellar gas in the Galactic anticentre hemisphere. The data show the presence, within the region explored and within the nearest 150 pc, of eight

We analyse spectral images across the full emission line in H_α of the discs of M100 and M101, extracting for each HII region its spectrum, and for the more luminous and extended, spectra over a range of circular apertures. The principal components of these spectra are presented in log-log plots of luminosity vs. turbulent line-width. These plots

We use the catalogue of HII regions obtained from a high quality continuum-subtracted H_α image of the grand-design spiral galaxy NGC 7479, to construct the luminosity function (LF) for the HII regions (over 1000) of the whole galaxy. Although its slope is within the published range for spirals of the same morphological type, the unusually strong