In the luminosity functions (LF's) of the HII regions of a set of late-type spiral galaxies we have identified the presence of a phase-change via a jump in the function accompanied by a change in slope.The nature of the phase-change is diagnosed using measurements of the internal radial surface brightness of individual regions.Plotting the internal

We investigate the radial variation of the magnetic field structure across sunspots, pores and azimuth centers (ACs). We define ACs as magnetic structures of about the same size as pores (all structures studied here are larger than 3 Mm diameter), but without a clear (at least 5%) continuum decrease associated with them. We start from the full 3D

We present a quantitative derivation of the recent star formation history (SFH) in different regions in the main body of NGC 6822. It has been performed using a set of model CM diagrams computed under different assumptions for the recent (~400 Myr) SFH and in which the crowding effects have been simulated using the particular crowding information

The study of BL Lac environments is hindered by the lack of knowledge regarding the environments of their putative parents, the FRI/II radio galaxies. To rectify this we have assembled a complete sample of FRI/II radio galaxies with z

We present new CCD narrowband images and spatially resolved intermediate-dispersion spectroscopy of the hydrogen-poor nebulae A30 and A58. These data have allowed us to obtain information on the physical properties and chemical abundances of the inner knots and outer envelopes of A30 and A58 as a basis for the discussion of their implications in

Most previous work studying the possible relation between the presence of non-axisymmetric structures such as bars and rings in a galaxy, and the presence of activity in their nuclei, has been hampered by imperfections in the selection of sample galaxies, and especially of a control sample of non-active galaxies. We have started to tackle this