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| « New Insights into Cosmic Dawn and Reionization from JWST » |
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Charlotte Mason
Cosmic Dawn Center, Niels Bohr Institute, University of Copenhagen (Copenhague, Danemark)
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The James Webb Space Telescope (JWST) has expanded our cosmic horizon to the first few hundred million years after the Big Bang, providing our first view of the earliest galaxies and supermassive black holes. These first sources drove the final cosmic phase transition by 're'-ionizing intergalactic hydrogen. The early stages and drivers of Reionization have been poorly understood, but identifying it began and which galaxies dominated the process is crucial for constraining poorly understood galaxy formation physics, including in galaxies below even JWST's detection limits. Excitingly, JWST has revealed an unexpected excess of galaxies at z > 9 and evidence of ionized regions already in place at z ˜ 7–14, pointing to a rapid build-up of galaxies at Cosmic Dawn that challenges theoretical models.
I will give an overview of what JWST has revealed about the star formation and ionizing properties of early galaxies, and the timing and morphology of reionization. I will discuss physical pictures which may explain the surprises at Cosmic Dawn and prospects for testing these scenarios with current and future observations.
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vendredi 6 juin 2025 - 11:00
Salle des séminaires Évry Schatzman, Institut d'Astrophysique de Paris
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Page web du séminaire / Seminar's webpage
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