Because of the intense brightness of the OB-type multiple star system σ Ori, the low-mass stellar and substellar populations close to the centre of the very young σ Orionis cluster is poorly know. I present an IJHK_s survey in the cluster centre, able to detect from the massive early-type stars down to cluster members below the deuterium burning

The aim of the present work is the detection of solar g-modes, by means of a new observational strategy based on the exploitation of their spatial and temporal properties. The basic data, obtained at the Observatorio del Teide in 1993, consists of daily solar velocity measurements taken continuously and sequentially at six different and symmetric

As part of the Dwarf galaxies Abundances and Radial-velocities Team (DART) program, we have measured the metallicities of a large sample of stars in four nearby dwarf spheroidal galaxies (dSph's): Sculptor, Sextans, Fornax, and Carina. The low mean metal abundances and the presence of very old stellar populations in these galaxies have supported

We performed a uniform and detailed analysis of 1112 high-resolution spectra of FGK dwarfs obtained with the HARPS spectrograph at the ESO 3.6 m telescope (La Silla, Chile). Most stars have effective temperatures 4700 K ≤ Teff ≤ 6300 K and lie in the metallicity range of -1.39 ≤ [Fe/H] ≤ 0.55. Our main goal is to investigate whether there are any

In the framework of the GLACE project, we present the preliminary results of a mapping of emission lines (Hα+[NII], Hβ and [OIII]) in the rich cluster Cl0024+1654 at z=0.4, using the red tunable filter of OSIRIS/GTC. This emission-line survey has been designed to detect emission-line galaxies (ELGs) whose fluxes correspond to SFR up to 2 M_&sun;/yr

We present deep surface photometry of a very faint, giant arc-loop feature in the halo of the nearby spiral galaxy NGC 5055 (M63) that is consistent with being a part of a stellar stream resulting from the disruption of a dwarf satellite galaxy. This faint feature was first detected in early photographic studies by van der Kruit; more recently, in