- [5/10] Escape of ionising photons from reionisation-era galaxies -- the view from the SPHINX simulations
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Escape of ionising photons from reionisation-era galaxies -- the view from the SPHINX simulations
Speaker: Dr. Joakim Rosdahl (Centre de Recherche Astrophysique de Lyon)
Date: 2019/5/10, Friday, 11am
Abstract:The epoch of reionisation marks a major shift from a cold neutral Universe to a warm ionised one, a transition which was thought to be powered by UV radiation emitted from young massive stars in the first galaxies.Our understanding of this epoch is still limited: observationally we glimpse a handful of the most luminous galaxies existing at the end of the epoch, but with the advent of the James Webb Telescope and other upcoming instruments we will soon start getting better information about the sources powering reionisation. Theoretically, the best way to gain an understanding is with cosmological simulations. However, those are very expensive, so either one simulates large patches of the reionising Universe without resolving the galactic sources, or one goes for tiny patches where the stellar sources inside one or a few galaxies are resolved, but the large-scale process is lost. I will present a new suite of simulations, called the SPHINX project, where we have developed new methods that allow us to perform radiation-hydrodynamical simulations of cosmic reionisation, resolving the emission and escape of radiation in the inter-stellar medium of thousands of galaxies all evolving together in the same simulation, hence capturing the interplay of multiple star-formation and feedback processes from ISM to IGM scales.I will show how the escape of ionising radiation from the SPHINX galaxies is regulated by stellar feedback and how this translates into an escape fraction of ionising photons that is sensitive to the evolution of the stellar population luminosity with age. I will show results from SPHINX on how the escape fractions vary with the local environment as well as large-scale galactic properties, and how the patchy reionisation of the SPHINX volume leads to the suppression of low-mass galaxy growth.
- Joakim Rosdahl