Infrared images of the Q0957+561 gravitational lens obtained with the Hubble Space Telescope show two large (~5") lensed images of the zs=1.41 quasar host galaxy. Parts of the host galaxy are doubly imaged, like the quasar, while other parts are quadruply imaged. The distortions of the host galaxy offer the best probe yet of the global structure of

We report on the optical properties of a sample of 30 BL Lac host galaxies in the redshift range 0.03

We have built a hybrid turbulence profiler measuring simultaneously the atmospheric turbulence structure with a Shack- Hartmann wave front sensor and a G-SCIDAR (scintillation sensor). This is the first instrument combining two different techniques to measure simultaneously the turbulence structure. The hybrid profiler has been installed at the

We introduce the Hydrangea simulations, a suite of 24 cosmological hydrodynamic zoom-in simulations of massive galaxy clusters (M200c = 1014-1015.4 M⊙) with baryon particle masses of ˜106 M⊙. Designed to study the impact of the cluster environment on galaxy formation, they are a key part of the `Cluster-EAGLE' project. They use a galaxy formation

Context. We study the time history of the yellow hypergiant HR 8752 based on high-resolution spectra (1973-2005), the observed MK spectral classification data, B - V- and V-observations (1918-1996) and yet earlier V-observations (1840-1918). Aims: Our local thermal equilibrium analysis of the spectra yields accurate values of the effective

Trojans are a significant portion of the small bodies population located within two clouds in the L4 and L5 Lagrangian points of Jupiter's orbit. The study of primitive small bodies is relevant to the origin and nature of volatile and organic material in the early Solar System. Dedicated studies of the nature of these bodies can significantly