We present Hubble Space Telescope (HST) observations of seven unusual objects from the HST ``snapshot survey'' of BL Lacertae objects, of which four are gravitational lens candidates. In three cases a double point source is observed: 0033+595, with 1.58" separation, and 0502+675 and 1440+122, each with ~0.3" separation. The last two also show one

We present the second part of the results of our spectroscopic study of orbital phase resolution of short-period active binaries. In this paper we present the observations of the binaries RT And, WY Cnc, and XY UMa, for which we obtained simultaneous low-resolution spectra in the Hα, Hβ, and Ca II infrared triplet (IRT; 8498 and 8542 Å) lines, and

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We present results of narrow-band and broad-band optical CCD imaging together with intermediate-resolution spectroscopy of the Wolf-Rayet galaxy Mkn 8. Analysis of the morphology and kinematics of the object indicates that the strong star formation episode we are witnessing in Mkn 8 is the product of the interaction of two (or three) disk galaxies

En esta Tesis se analiza la estructura de una mancha solar tipica, redonda, aislada y situada cerca del centro del disco solar, para 25 capas en profundidad óptica. Los datos fueron obtenidos con el "Advanced Stokes Polarimeter", uno de los mejores instrumentos disponibles, y la estratificación de los diferentes parámetros a lo largo de la

En la tesis se presenta un método para la inversión de los perfiles de Stokes de lineas espectrales para lasque la aproximación de Equilibrio Termodinámico Local no es adecuada. Este método es aplicado a observaciones espectro-polarimétricas realizadas con vistas al estudio de la dinámica y el magnetismo de la cromosfera sobre laumbra de las