Using spectroscopic data taken with OSIRIS spectrograph at the 10.4m-GTC telescope, we discover that the orbital period of the secondary star of the black hole binary XTE J1118+480, with an orbital period of P_{orb}˜ 4.1 hr, is rapidly decreasing. We have derived an orbital period time derivative of dot P=-1.83±0.66 ms yr^{-1} in this system

Active galactic nuclei (AGN) are powered by energetic phenomena which cannot be attributed to stars. Among AGN, several objects can be described by the unified model (Antonucci 1993; Urry & Padovani 1995). However, several subclasses of objects that cannot be accommodated into this scheme, as is the case of LINERs (low ionisation narrow emission

The formation and evolution of Local Group galaxies can be studied in the greatest possible detail thanks to the possibility of obtaining photometry and spectroscopy of their individual stars. I present an overview of different methods that can be combined for their study, and discuss recent results on the star formation history of a sample of

We present Gran-Telescopio-Canarias/OSIRIS optical spectra of 4 of the most compact and massive early-type galaxies in the Groth Strip Survey at redshift z 1, with effective radii R_e=0.5-2.4 kpc and photometric stellar masses M_⋆=1.2-4×10^11 M_⊙. We find these galaxies have velocity dispersions σ=156-236 km s^-1. The spectra are well fitted by

We have used the Two-Micron All-Sky Survey and the Wide-field Infrared Survey Explorer to look for ultracool dwarfs that are part of multiple systems containing main-sequence stars. We cross-matched L dwarf candidates from the surveys with Hipparcos and Gliese stars, finding two new systems. The first system, G255-34AB, is an L2 dwarf companion to

Context. OB stars are important in the chemistry and evolution of the Universe, but the sample of targets that is well understood from an asteroseismological point of view is still too limited to provide feedback on the current evolutionary models. Aims: We extend this sample with two spectroscopic binary systems. Our goal is to provide orbital