Evolving Spectra of Population III Stars: Consequences for Cosmological Reionization

  title={Evolving Spectra of Population III Stars: Consequences for Cosmological Reionization},
  author={Aparna Venkatesan and Jason Tumlinson and J. Michael Shull},
  journal={The Astrophysical Journal},
We examine the significance of the first metal-free stars (Population III) for the cosmological reionization of H i and He ii. These stars have unusually hard spectra, with the integrated ionizing photon rates from a Population III stellar cluster for H i and He ii being 1.6 and 10 5 times stronger, respectively, than those from a Population II cluster. For the currently favored cosmology, we find that Population III stars alone can reionize H i at redshifts of z ’ 9 and 4.7 and He ii at z ’ 5… 

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