We study the formation of the Li I lambda 6708 Angstroms resonance doublet in spectra of X-ray novae during the stage of outburst decay. We discuss the general conditions on accretion disc parameters which allow the detection of any spectral line absorption component in spectra of self-irradiated accretion discs. We obtain a simple analytical

Esta tesis representa un gran avance en nuestro conocimiento de la influencia del medioambiente en la evolución de las galaxias. El estudio se ha realizado midiendo el Ritmo de Formación Estelar (RFE) de galaxias pertenecientes a Grupos Compactos. Se ha basado endatos astronómicos de buena calidad, obtenidos en los Observatorios del Roque de los

We present a systematic study of the radial brightness profiles in H alpha of a set of H ii regions in 6 late-type spiral galaxies, complete down to stated limiting luminosities. We have sufficient linear resolution in our observations to be able to fit models in which the effects of the radial fall off in density and in mean degree of ionization

The recent result obtained by Givens and Kostinski [J. Mod. Opt. 40, 471 (1993)] successfully solves the old and important problem in polarization optics of characterizing a given 4×4 matrix as a Mueller matrix from a mathematical point of view. For practical purposes, however, a further elaboration on this result is needed, namely, the problem of

Deep V and I CCD images of the loosely populated Galactic globular cluster Pal 1 and the surrounding field have been obtained with the Isaac Newton Telescope. A color-magnitude diagram (CMD) down to V(lim) 24 and a luminosity function down to V(lim) = 23.25 have been constructed. Adopting a reddening E(V - I) = 0.20 +/- 0.04 and comparing the CMD

A quantitative comparison between the Milne-Eddington (ME) inversion technique implemented by Skumanich & Lites and the SIR (Stokes Inversion based on Response Functions) proposed by Ruiz Cobo & del Toro Iniesta is presented. Numerical experiments are carried out to explore the capabilities and limitations of both diagnostic techniques. Such