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

The planetary nebula NGC 2392 possesses an extremely unusual spectrokinematic morphology, characterized by several strange and elusive structures. In this paper, extensive narrowband imaging of the source is used to investigate the shell excitation structure, while [O III] and [S II] images are ratioed to provide fully sampled mapping of electron

Nowadays it is well established that BCDs are mostly old systems, as the vast majority of them have an extended low-surface brightness (LSB) stellar host underlying their central starburst component. This host generally extends several kpc from the star-forming (SF) regions, shows regular elliptical isophotes, and displays red colors indicative of

Studies of the mass function (MF) of open clusters of different ages allow us to probe the efficiency with which brown dwarfs (BDs) are evaporated from clusters to populate the field. Surveys in old clusters (age gtrsim 100 Myr) do not suffer so severely from several problems encountered in young clusters, such as intra-cluster extinction and large

We present a deep I, Z photometric survey covering a total area of 1.12 deg2 of the σ Orionis cluster and reaching completeness magnitudes of I = 22 and Z = 21.5 mag. From I, I - Z color-magnitude diagrams we have selected 153 candidates that fit the previously known sequence of the cluster. They have magnitudes in the range I = 16-23 mag, which

We study the thermal (tSZ) and kinetic Sunyaev-Zel'dovich (kSZ) effect associated with superclusters of galaxies using the MareNostrum (MNU) universe smoothed particle hydrodynamics (SPH) simulation. In particular, we consider superclusters with characteristics (total mass, overdensity and number density of cluster members) similar to those of the