This paper presents further results from our spectroscopic study of the globular cluster (GC) system of the group elliptical NGC 3923. From observations made with the GMOS instrument on the Gemini South Telescope, an additional 50 GC and ultra-compact dwarf (UCD) candidates have been spectroscopically confirmed as members of the NGC 3923 system

One of the next most important goals of astronomy is the characterization of exo-solar planets and the search for extra terrestrial life. Traditional spectroscopic measurements cannot be easily applied to the study of the atmospheres of the exo-solar planets, because the light reflected by the planet is overwhelmed by the radiation of the hosting

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Context. The fraction of binary stars is an important ingredient to interpret globular cluster dynamical evolution and their stellar population. Aims: We investigate the properties of main-sequence binaries measured in a uniform photometric sample of 59 Galactic globular clusters that were observed by HST WFC/ACS as a part of the Globular Cluster

The standard model of Active Galactic Nuclei (AGNs) predicts that Type 2 AGNs and Type 1 AGNs only differ in the orientation of a dust torus, which does or does not allow one to observe the central region. If the model is correct, the time-scales and the amplitudes of observed temporal variations should be different between obscured and unobscured

A virtual substrate for high quality InAs epitaxial layer has been attained via metalorganic vapor-phase epitaxy growth of Sb-assisted InxGa1-xAs metamorphic buffers, following a convex compositional continuous gradient of the In content from x = 53% to 100%. The use of trimethylantimony (or its decomposition products) as a surfactant has been