Aims: This programme is aimed at obtaining one of the largest X-ray selected samples of identified active galactic nuclei to date in order to characterise such...

We present the first results of our X-ray monitoring campaign on a 1.7 square degree region centered on Sgr A* using the satellites XMM-Newton and Chandra. The...

Context. A majority of massive stars are part of binary systems, a large fraction of which will inevitably interact during their lives. Binary-interaction...

Context: Determining the parameters of massive stars is crucial to understand many processes in galaxies and the Universe, since these objects are important...

Context. To understand the structure and evolution of massive stars, systematic surveys of the Local Group galaxies have been undertaken, to find these objects...

Context. Very low-metallicity massive stars are key to understanding the reionization epoch. Radiation-driven winds, chief agents in the evolution of massive...

We present a study of the MgII absorption system at z=0.558 towards the BL Lac object PKS 0118-272 based on high resolution spectra (λ/{DELTA}λ=~2x10^4^)...

A great deal of effort has been made in recent years to probe the gas fraction evolution of massive quiescent galaxies (QGs); however, a clear picture has not...

We have measured the ^12^C/^13^C interstellar ratio in the Coalsack, a prominent dark nebula in the southern sky, by means of high resolution (λ/δλ=6x10^4^)...