Model-independent evidence in favour of an end to reionization by z ≈ 6

  title={Model-independent evidence in favour of an end to reionization by z ≈ 6},
  author={Ian D. McGreer and Andrei Mesinger and Valentina D’Odorico},
  journal={Monthly Notices of the Royal Astronomical Society},
We present new upper limits on the volume-weighted neutral hydrogen fraction, , at z~5-6 derived from spectroscopy of bright quasars. The fraction of the Lyman-alpha and Lyman-beta forests that is "dark" (with zero flux) provides the only model-independent upper limit on , requiring no assumptions about the physical conditions in the intergalactic medium or the quasar's unabsorbed UV continuum. In this work we update our previous results using a larger sample (22 objects) of medium-depth (~ few… Expand

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