This paper presents observations made at intermediate spectral and spatial resolutions along the major and minor axes of the starburst galaxy NGC 253. The spectral ranges analyzed are in the region of the stellar Mg I b (~5175 Angstroms) line, in the near-IR Ca II triplet (~8550 Angstroms) absorption features, and in the region of the H alpha

We present a one-dimensional numerical scheme that allows for the simultaneous solution of the hydrodynamic equations coupled with energy and ionization equations. The code accounts for the time-dependent ionization of H, He, and He(+) and for radiative cooling derived from collisional excitation of C, N, O and Ne, whose ionization structures with

In a previous paper, we presented an atlas containing 59 low-resolution spectra that correspond to 27 Type Ia supernovae, covering about 1 year of Type Ia supernova evolution. This paper is a continuation, with the aim of performing a standard spectral evolution for ``normal'' Type Ia supernovae from the homogeneous set of data compiled in the

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Fragment-fragment-$gamma$ triple coincidence measurements of the $^{28}$Si~$+$~$^{28}$Si reaction at E$_{ m c.m.}$~=~55.8 MeV, carefully chosen to populate a well known quasi-molecular resonance in $^{56}$Ni, have been performed at the VIVITRON tandem facility by using the Eurogam Phase~II $gamma$-ray spectrometer. In the $^{28}$Si~$+$~$^{28}$Si

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