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We report the first results of a study of a sample of 20 galaxy mergers/interacting systems, using the VIMOS and PMAS integral field spectrographs. For each object, we extracted the integrated spectrum of the central regions and analyzed the ionization state using classical diagnostic diagrams citep{veil87}. There is evidence of AGN ionization in 4

This paper presents the results of a detailed theoretical investigation of the impact of non-LTE (NLTE) effects and of granulation inhomogeneities on the derived iron and oxygen abundances in the metal-poor halo subgiant HD 140283. Our analysis is based on both the ``classical'' one-dimensional stellar atmosphere models and on the new generation of

We study the two main corrections generally applied to narrow-band Hα fluxes from galaxies in order to convert them to star formation rates, namely for [NII] contamination and for extinction internal to the galaxy. From an imaging study using carefully chosen narrow-band filters, we find the [NII] and Hα emission to be differently distributed

Let $mathcal{K}$ be the space of properly embedded minimal tori in quotients of $R^3$ by two independent translations, with any fixed (even) number of parallel ends. After an appropriate normalization, we prove that $mathcal{K}$ is a 3-dimensional real analytic manifold that reduces to the finite coverings of the examples defined by Karcher, Meeks

From Hα images of a carefully selected sample of 57 relatively large, Northern spiral galaxies with low inclination, we study the distribution of the Hα emission in the circumnuclear and nuclear regions. At a resolution of around 100 parsec, we find that the nuclear Hα emission in the sample galaxies is often peaked, and significantly more often so