We present the results from a Gemini snapshot radial-velocity survey of 44 low-mass white-dwarf candidates selected from the Sloan Digital Sky Survey (SDSS) spectroscopy. To find sub-hour orbital period binary systems, our time-series spectroscopy had cadences of 2-8 min over a period of 20-30 min. Through follow-up observations at Gemini and the

On 17 August 2017, the Advanced LIGO and Virgo detectors observed the gravitational-wave event GW170817—a strong signal from the merger of a binary neutron-star system. Less than two seconds after the merger, a γ-ray burst (GRB 170817A) was detected within a region of the sky consistent with the LIGO–Virgo-derived location of the gravitational-wave

For the first time we show the detailed, late-stage, chemical evolution history of a small nearby dwarf spheroidal galaxy in the Local Group. We present the results of a high-resolution (R ~ 20 000, λ = 5340-5620; 6120-6701) FLAMES/GIRAFFE abundance study at ESO/VLT of 81 photometrically selected, red giant branch stars in the central 25' of the

Context: The analysis of transiting extra-solar planets provides an enormous amount of information about the formation and evolution of planetary systems. A precise knowledge of the host stars is necessary to derive the planetary properties accurately. The properties of the host stars, especially their chemical composition, are also of interest in

Sources responsible for volcanic unrest produce characteristic surface deformation. Given a sufficient number of distributed observation points, inversion is the preferred procedure for retrieving the source parameters of location and volume or pressure change. Most often the solutions have been for point sources embedded in a homogeneous half

Context: Planetary Nebulae (PNe) display complex radial surface brightness profiles whose understanding is crucial for a correct interpretation of their formation and evolution. In particular, the intermediate shells commonly observed around the bright rims of PNe contain important information for the discussion of the mass loss rate at the end of