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Etude des propriétés cinématiques et de la distribution de matière d'un échantillon de galaxies spirales et irrégulières

Abstract : We present some 2D kinematical data for a sample of 96 irregular and spiral galaxies, observed at H$\alpha$ wavelength (6563 Å). In the first chapter, we describe the GHASP survey on which is based this thesis. Then, we detail the instrumentation used for the observations (mainly a focal reducer, a scanning Fabry-Perot and a photon counting camera) and the steps of the data reduction. In the fourth part, we present the data for each galaxy : a monochromatic map, a 2D velocity field map and a rotation curve. The analysis of these data shows that : the shape of the rotation curve is dependent of both luminosity and morphological type; only early-type galaxies have a decreasing rotation curve; barred galaxies have an internal slope shallower than non-barred galaxies; low mass and low luminosity galaxies present the more asymmetric rotation curve; late-type galaxies (Sd, Sdm and Irr) present similar kinematical characteristics; the maximum extension of the H$\alpha$ disks depends on the morphological type and is correlated with the surface density of neutral gas at optical radius. In the last chapter, mass models have been realized for 23 galaxies using density profiles of cuspy and flat halos. Our mass models show that, for the majority of galaxies studied here, the dark halos are rather flat than cuspy whatever the morphological type, the luminosity or the maximum velocity in agreement with previous works based on rotation curves.
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Contributor : Olivia Garrido <>
Submitted on : Tuesday, October 4, 2005 - 1:35:52 PM
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Olivia Garrido. Etude des propriétés cinématiques et de la distribution de matière d'un échantillon de galaxies spirales et irrégulières. Astrophysique [astro-ph]. Université de Provence - Aix-Marseille I, 2003. Français. ⟨tel-00010386⟩

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