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Detecting the rise and fall of the first stars by their impact on cosmic reionization
journal contribution
posted on 2023-06-08, 15:12 authored by Kyungjin Ahn, Ilian IlievIlian Iliev, Paul R Shapiro, Garrelt Mellema, Jun Koda, Yi MaoThe intergalactic medium was reionized before redshift z ~ 6, most likely by starlight which escaped from early galaxies. The very ?rst stars formed when hydrogen molecules (H2) cooled gas inside the smallest galaxies, minihalos of mass between 105 and 108 solar masses, before redshift z ~ 40. Minihalo stars then started reionization but could not ?nish it before the rising background of H2-dissociating soft-ultraviolet starlight choked them o?. We con?rm this hypothesis by the ?rst large-scale radiative transfer simulations to include minihalo sources and their suppression. We show that reionization began much earlier with minihalo sources than without, and was greatly extended, which boosts the intergalactic electron-scattering optical depth and the large-angle polarization ?uctuations of the cosmic microwave background signi?cantly. Although within current WMAP uncertainties, this boost should be readily detectable by Planck. If reionization ended as late as z ov 7, as suggested by other observations, Planck will thereby see the signature of the ?rst stars at high redshift, currently undetectable by any other probe. We also show that minimal reionization models satisfying both the late reionization condition, zov . 7, and the large optical depth condition, tes & 0.085, can be distinguished from our ?ducial model under the same constraints by Planck at high con?dence level.
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Publication status
- Published
File Version
- Published version
Journal
Astrophysical Journal LettersISSN
2041-8205Publisher
Institute of PhysicsExternal DOI
Issue
1Volume
756Page range
L16Department affiliated with
- Physics and Astronomy Publications
Full text available
- Yes
Peer reviewed?
- Yes
Legacy Posted Date
2013-06-10First Open Access (FOA) Date
2013-06-10First Compliant Deposit (FCD) Date
2013-06-07Usage metrics
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