We propose a method to build a suitable control sample (CS) in order to isolate the effect of galaxy interactions by using mock galaxy catalogues. This analysis shows that several bias effects in the selection of the CS have to be overcome for a reliable comparison.

La Palma Observatory offers four multi-object spectrographs installed on 4 and 10 m class telescopes. We present an overview of these four instruments. As a scientific case for two of them, we present the optical follow-up of Sunyaev-Zeldovich (SZ) sources undertaken by the Planck collaboration, focused on the detection, redshifts determination and

Context. Found within the central molecular zone, the Quintuplet is one of the most massive young clusters in the Galaxy. As a consequence it offers the prospect of constraining stellar formation and evolution in extreme environments. However, current observations suggest that it comprises a remarkably diverse stellar population that is difficult

A high resolution spectrum (Δλ = 0.2 Å) of the Population II star HD 76932 from the archive of the IUE satellite has been analysed in a search for measurable resonance absorption lines due to 9Be. Matching the observations by a synthesized model of the wavelength region around the doublet at 3130 Å gives a conservative upper limit for the abundance

We are performing a survey of a sample of 17 radio jets with Chandra and HST, with the aim of finding their X-ray and optical counterparts. In this paper, we present the preliminary Chandra results for the first six sources observed and analyzed so far. In four of them an X-ray jet is clearly detected. We compare the X-ray morphologies to the radio

We observed the neutron star X-ray transient 2S 1803-245 in quiescence with the X-ray satellite XMM-Newton, but did not detect it. An analysis of the X-ray bursts observed during the 1998 outburst of 2S 1803-245 gives an upper limit to the distance of