We present the first entirely ground-based astrometric determination of the proper motion for the Fornax Local Group dwarf spheroidal satellite galaxy of the...

We present what we believe to be the first truly simultaneous UBVRI photopolarimetric results for a sample of eight 'normal' quasars. In five of these quasars...

Aims:To check whether the polar angle distribution of QSOs around nearby spiral galaxies is isotropic or not. Methods: A statistical analysis of the polar angle...

Context. The nature of ultra-luminous X-ray (ULX) sources is still a matter of debate. Studies of their counterparts in other spectral ranges will help to...

Primordial abundances of light elements are sensitive to the physics of the early Universe and can directly constrain cosmological quantities, such as the...

The strong intervening absorption system at redshift 1.15 towards the very bright quasar HE 0515−4414 is the most studied absorber for measuring possible...

An attempt is made to confirm the observation of Allen (1980) of a 3.3-micron emission feature attributed to thermal dust emission in the quasar 3C 273...

The Gaia Galactic survey mission is designed and optimized to obtain astrometry, photometry, and spectroscopy of nearly two billion stars in our Galaxy. Yet as...

Context. Since July 2014, the Gaia mission has been engaged in a high-spatial-resolution, time-resolved, precise, accurate astrometric, and photometric survey...