We studied the fraction and properties of bars in a sample of about 3000 galaxies extracted from SDSS-DR5. This represents a volume limited sample with galaxies located between redshift 0.01 -20, and inclination i < 60°. Interacting galaxies were excluded from the sample. The fraction of barred galaxies in our sample is 45%. We found that 32% of

Context: The presence of pulsations in late-type Be stars is still a matter of controversy. It constitutes an important issue to establish the relationship between non-radial pulsations and the mass-loss mechanism in Be stars. Aims: To contribute to this discussion, we analyse the photometric time series of the B8IVe star HD 50 209 observed by the

We introduce a new scheme to study the nature of the central engine in a lensed QSO. The compact emission regions could have different sizes in different optical wavelengths, and our framework permits us to obtain the source size ratios when a microlensing special high-magnification event (e.g., a caustic crossing event, a two-dimensional maximum

We present our latest results based on the Spitzer Cosmological Surveys about the characterization of the mass assembly of galaxies in the last 12 Gyr. We have analyzed the stellar mass function up to z=4 using a sample of galaxies selected in the rest-frame near-infrared with Spitzer/IRAC, and the SFR function using MIPS data. Our results confirm

We study the two-dimensional kinematics of the Hα-emitting gas in the nearby barred Scd galaxy NGC 6946, in order to determine the pattern speed of the primary m=2 perturbation mode. The pattern speed is a crucial parameter for constraining the internal dynamics, estimating the impact velocities of the gravitational perturbation at the resonance

We have studied the quantitative morphology and structural parameters of the bright galaxy population in the Nordic Optical Telescope (NOT) sample, which consists of five clusters of galaxies within the redshift range 0.18 ≤ z ≤ 0.25, imaged in the central 0.5-2 Mpc in very good seeing conditions. We have obtained that the structural parameters of