As part of our deep multi-colour survey of two gravitational lensing clusters, Abell 1835 (z=0.252) and AC114 (z=0.312) used to search for very high redshift galaxies we have detected a number of extremely red galaxies (EROs, R-K[s]> 5.6). Following up on our deep optical and near-IR imaging (Richard et al. 2006) we used deep HST/ACS imaging in the

Large HI shells, with diameter of hundreds of pc and expanding with velocities of order 10-20 kms^-1 have been detected in their hundreds in the Milky Way and are well observed features of local gas rich galaxies. These shells could well be predicted as a result of the impact of OB associations on the ISM, but doubt has been cast on this scenario

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We present the results of a dynamical analysis of the radio-halo cluster A2744 based on optical data. We find that this cluster is in an advanced merging phase, with two galaxy subsystems impacting along a direction close to the line- of-sight, likely observed just after the core passage.

The determination of the extinction in different directions in the Galaxy and in external galaxies is of paramount importance in several fields of astrophysics. The determination of the extinction law provides clues to the nature of the Inter/Circum-Stellar Medium (ISM/CSM), specifically to that of the dust particles. Recent studies have shown that