Formation et Evolution des Galaxies - Groupe de Recherche IAP

Date	Sujet	Présenté par
1 juin 2017	Reverse engineering galaxies: the Lyman Alpha Reference Sample (LARS) The "(Extended) Lyman Alpha Reference Sample" is a multi-wavelength survey of 42 local laboratory star-forming galaxies that is studying the detailed physics of the production, propagation, and visibility of Hydrogen Lyman-alpha photons. Lyman-alpha emission is the most common method used to identify high-redshift galaxies. However, it is a resonance line, and photons scatter whenever they encounter neutral hydrogen atoms at rest velocity; this leads to an enormously complex radiative transport that depends critically on the morphology and kinematics of the HI gas. I will present scientific highlights from the "Lyman Alpha Reference Sample" observing campaign, with a specific focus on the suite of HST imaging and spectroscopy and VLA HI 21cm imaging. This program has produced the first direct comparisons of the HI morphology and dynamics with the locations and intensities of Lyman-alpha emission in galaxies, and is probing the physics that governs Lyman-alpha radiative transport in a statistically robust and cosmologically representative sample of galaxies. The results will serve as the foremost interpretive benchmark for models of Lyman-alpha radiative transport and for data from the forthcoming ground-based surveys that will detect millions of galaxies via Lyman-alpha emission in the next decade.	John Cannon Dept. Physics and Astronomy, Macalaster College, Saint Paul, Minnessota, USA

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