Transfert radiatif dans les galaxies à Grand Redshift

Abstract : The Epoch of Reionisation, which spans during the first billion year of te Universe, corresponds to the period during which the first stars and galaxy form. In this context, the main topic of this thesis is to study the formation of those early structures and their radiative feedback to their environment. For this purpose, I use various numerical simulations tools designed to model the radiative transfer in galaxies in a cosmological framework.More specifically, I look at very small galaxies, which are believed to contribute the bulk of the photons required to reionise the Universe. I explore this idea using radiative hydrodynamics simulations performed with RAMSES-RT, focusing on three small galaxies with a very high spatial and temporal resolution. I first detail the mechanism that regulate te production and escape of ionising photons in galaxies, and I show that supernovae explosions are a crucial element for this regulation. I then started to investigate the observable properties of those galaxies.In a second part of my thesis, I developped an extension to the Monte Carlo radiative transfer code MCLya to take light polarisation into account and to model the diffuse emission. I applied this code to post-process the simulation of a Lyman-alpha blob (an extended Lyman-alpha source), and to study its polarisation properties with mock observations. Contrary to what was suggested before, I showed that polarisation is not a strong tracer of the origin of Lyman-alpha photons
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Submitted on : Friday, November 25, 2016 - 11:58:09 AM
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  • HAL Id : tel-01402895, version 1



Maxime Trebitsch. Transfert radiatif dans les galaxies à Grand Redshift. Astrophysique [astro-ph]. Université de Lyon, 2016. Français. ⟨NNT : 2016LYSE1119⟩. ⟨tel-01402895⟩



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