Séminaire/Seminar Galaxies |
| « Local clues to the drivers of reionization » |
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John Chisholm |
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Early galaxies produced a sufficient number of ionizing photons to ionize all the hydrogen between galaxies, but the source of these ionizing photons is still unconstrained. These sources established the conditions for modern galaxy evolution, and crucially shaped the subsequent morphology of large-scale structure.
The James Webb Space Telescope aims to constrain the sources of ionizing photons, but the neutral intergalactic medium precludes many direct detections of ionizing photons at high redshift. Recently, we uncovered the first statistical sample of low redshift galaxies that emit ionizing photons. These observations provide local laboratories to test indirect methods of determining the escape of ionizing photons. Here, I will discuss some of these successes, but some challenges remain. The largest obstacle to constraining reionization remains the large empirical scatter between direct detections of ionizing photons and the indirect indicators. I will discuss how geometry may explain this scatter. If James Webb Space Telescope probes large enough samples, these indirect indicators will provide an estimate of the ionizing emissivity of high redshift galaxies. |
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jeudi 12 mai 2022 - 11:30 Salle des séminaires Évry Schatzman Institut d'Astrophysique de Paris |
| Page web du séminaire / Seminar's webpage |