En la memoria de Tesis se recoge un archivo de espectros de supernovas. Para cada supernova estudiada se ha procurado obtener una secuencia de espectros que abarque la mayor parte de su historia evolutiva. Este trabajo es el resultado de un esfuerzo de muchos años durante los que se han ido observando un gran número de objetos. Además de su

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In this work we study the galaxy NGC4736, using narrow band interference filters imaging centered at the emission lines {Oii} {3727+3729}, Hβ, {Oiii} {5007}, Hα, {Sii} {6716+6730} and {Siii} {9070} and nearby continua. We have obtained sizes, positions, emission line absolute fluxes, and continua intensities for 90 Hii regions, mainly distributed

We find a strong correlation between the optical outburst amplitude and orbital period for the soft X-ray transient sources with orbital periods less than 1 d. By fitting the observed values for eight X-ray transients, we determine an empirical relation that can be used to predict the orbital period of an X-ray transient given only its outburst

Within the classical Eulerian theory of gravitational instability, and in an Omega = 1 universe, we introduce a method for obtaining iterative solutions for the density contrast and peculiar velocity that can be extended to any order of approximation in the quasilinear regime. We compute the solution up to the fourth order (E4) and establish a

The huge photometric databases that are being created for stars in the Magellanic Clouds and in Local Group galaxies not only allow a detailed study of the star formation history of these systems but also provide important information on stellar evolutionary theory. Two low-level features above the red clump in the LMC color-magnitude diagram (CMD)