The regions of high excitation gas detected around various Active Galactic Nuclei (AGN) are examined. The radiation emitted by the nucleus may be responsible for the high ionization of the line emitting gas. Evidence that the radiation field is anisotropic and collimated in a direction close to the cone axis is found. The possibility that a

LA MEMORIA PRESENTADA POR D. ANTONIO FERRIZ MAS ES UN TRABAJO TEORICO ORIGINAL Y RIGUROSO SOBRE DIVERSOS ASPECTOS MATEMATICOS Y FISICOS DE LA DINAMICA DE UN PLASMA CONFINADO EN UN TUBO DE FLUJO MAGNETICO INTENSO. EL AUTOR DE ESTA MEMORIA, EN UN ESTUDIO EMINENTEMENTE TEORICO, LOGRA SUS OBJETIVOS CIENTIFICOS MEDIANTE CALCULOS ANALITICOS, UTILIZANDO

LA ASTROSISMOLOGIA O SISMOLOGIA ESTELAR ESTUDIA EL ESPECTRO DE MODOS PROPIOS DE OSCILACION DE LAS ESTRELLAS CON EL OBJETIVO PRINCIPAL DE PROPORCIONAR INFORMACION SOBRE LA ESTRUCTURA INTERNA DE LAS MISMAS Y SU ESTADO EVOLUTIVO. COMO TAL, ES UNA CIENCIA SUMAMENTE JOVEN PUES DATA, TAN SOLO, DE LA ULTIMA DECADA (1979-89), AUNQUE SE LA PUEDE CONSIDERAR

Doppler velocity data are used to study solar cycle variation of the frequencies of solar acoustic oscillations from 1977 to 1988. The results show a clear shift in frequency of the cross-correlation peaks of -0.37 + or - 0.04 microHz peak to peak as the solar activity cycle progresses from maximum to minimum. This effect is dependent on the l

The observations of the low-mass x ray binary, Cyg X-2, taken with the International Ultraviolet Explorer (IUE) in a campaign conducted in June and October of 1988 are reported. A direct relationship between the strength of the UV continuum and line emission and the placement of the x ray spectrum in one of three branches of the so-called Z-shaped

High resolution, high signal to noise spectral profiles of the 8498 and 8542 A lines of the Ca II infrared triplet (IRT) have been obtained for a sample of late type dwarfs, with a wide range of levels of chromospheric activity, in the spectral range F9 to K4/5. These profiles, and the difference profiles for selected active and quiescent objects