A fierce new challenge: unveiling the connection between the first galaxies and reionization

The formation of the first galaxies in the Universe is the new frontier of both galaxy formation and reionization studies. In fact, we are starting to directly observe primeval galaxies thanks to the James Webb Space Telescope, and soon we will witness the reionization process through 21cm intensity mapping experiments. This unique moment creates a fierce new challenge, namely to simultaneously understand in a unique and coherent picture the processes of galaxy formation and reionization, and – crucially – their connection. The latter, in particular, has escaped past numerical efforts. In this talk I will introduce an years-long effort geared toward achieving such comprehensive picture, recently culminated in the Thesan suite of cosmological radiation-magneto-hydrodynamical simulations. I will briefly introduce the features of Thesan, highlighting the successes and failures of its physical model, and then focus on probes of the mesoscales between galaxies and IGM. Thesan can, for the first time, reproduce the modulation of the Lyman-alpha flux around galaxies, and explain its physical origin. This opens up a new avenue to constrain sources and timing of reionization. Finally, I will outline the future path towards a more comprehensive understanding of the first billion years of the Universe.
Host: Marcos Pellejero
ZOOM:  https://dipc-org.zoom.us/j/95934141397YouTube: https://youtu.be/8NjJ5BYfum0

Hybrid Seminar: Donostia International Physics Center


Enrico Garaldi, Max Planck Institut, Germany

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