We present a chemical abundance analysis of the secondary star in the black hole binary V404 Cygni, using Keck I/High Resolution Spectrometer. We adopt a χ2-minimization procedure to derive the stellar parameters, taking into account any possible veiling from the accretion disk. With these parameters we determine the atmospheric abundances of O, Na

Using high-resolution (R~30000), high-quality (S/N>=60 per pixel), we obtained spectra for twelve stars in four open clusters with the fibre spectrograph FOCES, at the 2.2 Calar Alto Telescope in Spain.We employ a classical equivalent-width analysis to obtain accurate abundances of sixteen elements: Al, Ba, Ca, Co, Cr, Fe, La,Mg, Na, Nd, Ni, Sc, Si

Sixteen years of observations of black hole transients with the Rossi X-ray Timing Explorer, complemented by other X-ray observatories and ground-based optical/infrared/radio telescopes have given us a clear view of the complex phenomenology associated with their bright outbursts. This has led to the definition of a small number of spectral/timing

We present the largest data base so far of atmospheric optical turbulence profiles [197 035 individual C2N(h)] for an astronomical site, the Roque de los Muchachos Observatory (La Palma, Spain). This C2N(h) data base was obtained through generalized SCIDAR observations at the 1-m Jacobus Kapteyn Telescope from 2004 February to 2009 August

Context. Ground-based imaging and imaging spectropolarimetric data are often subjected to post-facto reconstruction techniques to improve the spatial resolution. Aims: We test the effects of reconstruction techniques on two-dimensional data to determine the best approach to improve our data. Methods: We obtained an 1-h time-series of

Evolved stars observed within the Penn State - Torun Center for Astronomy Planet Search (PTPS) conducted with the Hobby-Eberly Telescope are supposed to present various effects of activity. In addition to chromospheric activity and/or pulsations one may expect spots temporarily appearing on their surfaces and rotating with stars that mimic