We present high-quality, wide spectral coverage long-slit optical spectra for 12 powerful radio sources at low and intermediate redshifts (z 0.7) that show evidence for a substantial ultraviolet (UV) excess. These data were taken using the William Herschel Telescope and the ESO Very Large Telescope with the aim of determining the detailed

Sporadic cometary-like activity has been observed in three asteroids of the main belt (the Main Belt Comets, MBCs, Hsieh and Jewitt 2006, Science, 312, 561): (7968) Elst-Pizarro, 118401 (1999 RE70) and P/2005 U1 (Read). All of them are members of the Themis family. The study of this objects is of fundamental importance to address several

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 present a detailed study on the surface composition of 2003 EL61. We use visible and near-infrared spectra of 2003 EL61 obtained for more than three consecutive hours covering more than 80% of the rotational period, in the Telescopio Nazionale Galileo and William Herschel Telescope, sited in the Observatorio del Roque de los Muchachos. First we

This paper describes the Fifth Data Release (DR5) of the Sloan Digital Sky Survey (SDSS). DR5 includes all survey quality data taken through 2005 June and represents the completion of the SDSS-I project (whose successor, SDSS-II, will continue through mid-2008). It includes five-band photometric data for 217 million objects selected over 8000 deg2

We present a comprehensive study of the observational dependence of the mass-loss rate in stationary stellar winds of hot massive stars on the metal content of their atmospheres. The metal content of stars in the Magellanic Clouds is discussed, and a critical assessment is given of state-of-the-art mass-loss determinations of OB stars in these two