Some studies of the Milky Way halo and all studies of the thick disk populations suffer from difficulties cleanly separating out one galactic component from another. This is largely due to magnitude limitations, which produces a bias towards local solar neighborhood samples, where the separation of the thick disk from the halo populations of the

We report the discovery of a very bright (r = 20.16), highly magnified, and yet intrinsically very luminous Lyα emitter (LAE) at z=2.82. This system comprises four images in the observer plane with a maximum separation of ∼ 6\prime\prime and it is lensed by a z=0.55 massive early-type galaxy. It was initially identified in the Baryon Oscillation

The covariance of ground-based lucky images is a robust and easy-to-use algorithm that allows us to detect faint companions surrounding a host star. In this paper, we analyse the relevance of the number of processed frames, the frames' quality, the atmosphere conditions and the detection noise on the companion detectability. This analysis has been

We combine observational data on a dozen independent cosmic properties at high-z with the information on reionization drawn from the spectra of distant luminous sources and the cosmic microwave background (CMB) to constrain the interconnected evolution of galaxies and the intergalactic medium since the dark ages. The only acceptable solutions are

In a new classical Weyl 2-spinor approach to non abelian gauge theories, starting with the U(1) gauge group in a previous work, we study now the SU(3) case corresponding to quarks (antiquarks) interacting with color fields. The principal difference with the conventional approach is that particle-field interactions are not described by means of

Context. Stellar kinematic groups are kinematically coherent groups of stars that might have a common origin. These groups spread through the Galaxy over time owing to tidal effects caused by Galactic rotation and disk heating. However, the chemical information survives these processes. Aims: The information provided by analysis of chemical