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Accueil > Séminaires > SEMINAR CANCELED !!! The 3D Distribution

SEMINAR CANCELED !!! The 3D Distribution of Interstellar Gas and Dust in the Galaxy : Gaia-Related Preparatory Work

Lucky Puspitarini

3D Galactic ISM maps are a potential tool of wide use, but accurate and detailed maps are still lacking. One way to obtain three-dimensional (3D) descriptions, which include its direction and distance, is to record a large set of individual absorption or reddening measurements toward target (background) stars located at various known distances and directions. The inversion of these measurements using a robust tomographic method can produce the spatial distribution of the ISM. Until recently absorption data were very limited and distances to the target stars lacking or uncertain, but the situation will greatly improve thanks to current and future massive stellar surveys from ground, and to the Gaia mission. Extracting interstellar (IS) absorption data from a large number of stellar spectra requires new tools : we have developed automated spectral analysis tools adapted to different IS tracers, such as NaI lines, CaII lines, diffuse interstellar bands (DIBs) as well as to early- or late-type stars, thanks to synthetic stellar spectra based on the known stellar parameters. We also developed a global analysis to fit simultaneously multiple IS tracers, allowing to understand their relationships and to derive their kinematic information at the same time. I will show applications of the tools to several datasets including Gaia-ESO Spectroscopic Survey (GES) spectra, and show the potentiality of DIBs to trace the ISM in the Galaxy. I will finally briefly show and comment the latest 3D map of the nearby ISM describing the Gould Belt, cavities (or bubbles), and the determination of the local bubble (LB) hot gas pressure owing to the comparison with soft X-ray emission maps.