Hydrogen reionisation ends by $z=5.3$: Lyman-$\alpha$ optical depth measured by the XQR-30 sample

  title={Hydrogen reionisation ends by \$z=5.3\$: Lyman-\$\alpha\$ optical depth measured by the XQR-30 sample},
  author={Sarah E. I. Bosman and Frederick B. Davies and George D. Becker and Laura C. Keating and Rebecca L. Davies and Yong Zhu and Anna-Christina Eilers and Valentina D’Odorico and Fuyan Bian and M. Bischetti and Stefano Cristiani and Xiaohui Fan and Emanuele Paolo Farina and Martin G. Haehnelt and Girish Kulkarni and Andrei Mesinger and Romain A. Meyer and Masafusa Onoue and Andrea Pallottini and Yuxiang Qin and Emma V. Ryan-Weber and Jan-Torge Schindler and Fabian Walter and Feige Wang and Jinyi Yang},
The presence of excess scatter in the Ly-α forest at z ∼ 5.5, together with the existence of sporadic extended opaque Gunn-Peterson troughs, has started to provide robust evidence for a late end of hydrogen reionisation. However, low data quality and systematic uncertainties complicate the use of Ly-α transmission as a precision probe of reionisation’s end stages. In this paper, we assemble a sample of 67 quasar sightlines at z > 5.5 with high signal-to-noise ratios of > 10 per ≤ 15 km s−1… 

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