The role of galactic winds in galaxy evolution and formation using 3D spectroscopy

2017 
The Λ-CDM model is one of the most resounding triumphs of modern cosmology. Yet, even though it is immensely successful at explaining the dark matter dominated large scale structures, it fails, sometimes dramatically, when the complex physics of baryonic matter comes into play. In particular, one of the major remaining discrepancies is between the observed and predicted baryonic densities of the dark matter halos of galaxies both in the high mass and low mass regimes (e.g. Behroozi et al., 2013b). Theoretical models predict much more mass than is actually observed, leading to the conclusion that there are mechanisms at play ejecting part of the baryonic matter reservoir from galaxies and therefore affecting their evolution. In other words, if we want to understand the evolution of galaxies, it is essential to understand precisely how galaxies lose a fraction of their baryonic matter. For low mass galaxies, a key part of the solution lies on supernovae-driven outflows (Dekel & Silk, 1986). Not only can such outflows efficiently expel gas and metals from galactic disks, enriching the inter-galactic medium (Oppenheimer et al., 2010), they are also observed in almost every star-forming galaxy (Veilleux et al., 2005a), making them an important part of the matter cycle of galaxies in general. Our incomplete knowledge of scaling relations between galaxies and the properties of their outflowing material, such as between the star formation rate (SFR) and the ejected mass rate Mout, limits our ability to produce accurate numerical simulations of galaxy evolution. The objective of this thesis is to quantify galactic wind properties using background quasars and 3D spectroscopy. In order to achieve our goal, we use large data sets from several instruments (SDSS, LRIS at Keck, SINFONI, UVES and MUSE on VLT). After developing observational strategies in order to have the largest data set possible with this technique, we increased the number of observations by 1 order of magnitude which resulted in better constraints on the outflowing materials for the low mass galaxies.
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