H_α luminosities of a sample of galaxies in nearby compact groups are presented. Our purpose is to study the influence of the group environment on the star formation rates (SFRs) of the galaxies in the groups, provided that the H_α luminosity is a good tracer of the SFR of disc galaxies. Measuring the global L/L_B of the groups - including early

We investigate a one-zone chemo-photometric evolutionary model of truncated spiral galaxies with and without starbursts in order to explore the origin of the spectrophotometric properties of S0s. First, we show that 1) the tight U-V colour-magnitude (CM) relation cannot reject the model with a starburst and 2) the model with a starburst can explain

We have used photometric images of ten barred galaxies in the B and I bands to infer the geometrical and dynamical parameters of their bars: Their length, (R_bar), their strengths, (S_b), and their corotation radii, (R_CR). These parameters have been obtained studying azimuthal profiles from the B and I band images of the galaxies. We find that R

A search for star-forming objects belonging to tidal tails has been carried out in a sample of deep Hα images of 16 compact groups of galaxies. A total of 36 objects with Hα luminosities greater than 1038 ergs s-1 has been detected in five groups. The fraction of the total Hα luminosity of their respective parent galaxies shown by the tidal objects

Searching for subtle dips in brightness is all the rage among astronomers seeking Earthlike planets beyond the solar system.

We report the detection of main-sequence and blue horizontal-branch stars of the Ursa Minor dwarf spheroidal galaxy beyond its tidal radius, indicating the existence of a possible tidal extension in this satellite of the Milky Way. This tidal extension could spread out well beyond the area covered in our survey (R>80'), as suggested by the presence