Aims:Large HI shells, with diameters of hundreds of pc and expansion velocities of 10-20 km s-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 by the

We present first results of a spectroscopic multisite campaign for 12 (DD) Lacertae (hereinafter 12 Lac). This star is one of the best observed β Cephei stars. It has a large number of known oscillation frequencies but a lack of identified m-values for its detected modes. In our data set we find seven independent frequencies together with

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Distant clusters of galaxies provide a powerful method to study the formation and evolution of galaxies and large scale structure of the Universe. However, the number of known clusters at high redshift (z > 0.5) is still limited. As a preparatory work for detailed studies with GTC, we are building a catalogue of such objects analyzing public deep

The 3C Database aims to provide complete multi-wavelength information over different cosmological fields, such as GOODS, Groth or Sa68 allowing detailed studies on wide samples of galaxies.

The UKIRT Infrared Deep Sky Survey (UKIDSS) Large Area Survey (LAS) presents an unparallelled resource for the study of field brown dwarfs. The UKIDSS Cool Dwarf Science Working Group (CDSWG) is carrying out a search for the lowest temperature brown dwarfs ever discovered, with the possibility of identifying a new spectral class of ultracool dwarf