Spectral synthesis calculations in stellar (magnetized) atmospheres are based on the solution of the radiative transfer equation (RTE) for polarized light. The thermodynamic and magnetic properties of the atmospheres, along with the radiation field, completely specify the basic ingredients of the RTE, after which numerical methods have to be

We have made B, V, and I-band observations of satellite galaxies which lie around isolated disk galaxies, using the satellite sample of Zaritsky et al. (1997). We present 3D light profiles of the centers of these satellites, and discuss how we plan to use the profiles to study the survival or disruption of satellites in minor mergers, an issue that

We present the integrated Hα emission line profile for 157 HII regions in the central 3.4 × 3.4 arcmin2 of the galaxy M83 (NGC 5236). Using the Fabry-Perot interferometer GHαFAS, on the 4.2-m William Herschel Telescope on La Palma, we show the importance of a good characterization of the instrumental response function for the study of line profile

The molecular carriers of the ubiquitous absorption features called the diffuse interstellar bands (DIBs) have eluded identification for many decades, in part because of the enormous parameter space spanned by the candidates and the limited set of empirical constraints afforded by observations in the diffuse interstellar medium. Detection of these

We present near-infrared photometry (J band) and low-resolution optical spectroscopy (600-1000 nm) for one of the faintest substellar member candidates in the young σ Orionis cluster, S Ori 47 (I=20.53; Béjar, Zapatero Osorio, & Rebolo). Its very red (I-J) = 3.3+/-0.1 color and its optical spectrum allow us to classify S Ori 47 as an L1.5-type

We propose a method to build a suitable control sample (CS) in order to isolate the effect of galaxy interactions by using mock galaxy catalogues. This analysis shows that several bias effects in the selection of the CS have to be overcome for a reliable comparison.