Séminaire Doctoral / Seminar PhD |
| « The lyman alpha forest and correlation with galaxies in the Cosmic Dawn III simulation » |
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Joe Lewis |
| The study of Reionization requires relating two separate data-sets: observations of the IGM, and of galaxies. Innovative surveys like EIGER (Kashino+23) are shedding new light on the correlation between galaxy density and local Lyman-alpha forest transmission. To accompany the interpretation of this new dataset, we use the Cosmic Dawn III simulation (CoDa III). CoDa III is a massive cosmological radiation and hydrodynamics simulation, which has been shown to have a good agreement with IGM constraints during Reionization (Lewis,Ocvirk+22). As of such, it is uniquely positioned to explore these correlations. First, we forward model Lyman-alpha observations in thousands of lines of sight, finding that the resulting evolution of the mean effective optical depths and their distributions are in good agreement with observations. Second, we compute the transmission in radial bins surrounding millions of galaxies. We find that the transmission decreases close to galaxies. However, the simulation suggests that the correlation heavily depends on the sample of galaxies and the number of Lyman-alpha lines of sight. When using similar sample sizes to the observations from EIGER, the obtained correlation can vary wildly in shape and normalisation within a few pMpc of radial distance from the sample galaxies. |
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vendredi 29 novembre 2024 - 16:00 Salle des séminaires Évry Schatzman, Institut d'Astrophysique |
| Page web du séminaire / Seminar's webpage |