The detectability of high-redshift Lyα emission lines prior to the reionization of the universe Haiman, Zoltán For a source of Lyα radiation embedded in a neutral intergalactic medium (IGM) prior to the reionization epoch, the Lyα emission line is strongly suppressed by the intervening IGM. The damping wing of the so-called Gunn-Peterson trough can extend to the red side of the emission line and erase a significant fraction of the total line flux. However, the transmitted fraction increases with the size of the local cosmological H II region surrounding the source, and therefore with the ionizing luminosity and age of the source. Motivated by the recent discovery of a Lyα-emitting galaxy at a redshift z = 6.56 (Hu et al.), possibly prior to the reionization of the IGM, we revisit the effects of a neutral IGM on the Lyα emission line. We show that for faint sources with little or even no ionizing continuum, a sufficiently broad (Δv ≳ 300 km s^-1) emission line can still remain observable. In particular, the line detected by Hu et al. is consistent with a source embedded in a neutral IGM. We provide characterizations of the asymmetry and total transmitted flux of the Lyα line as functions of the ionizing emissivity of its source. We argue that a statistical sample of Lyα emitters extending beyond the reionization redshift can be a useful probe of reionization. American Astronomical Society 2002 info:eu-repo/semantics/article doc-type:article text http://purl.org/coar/resource_type/c_2df8fbb1 https://research-explorer.ista.ac.at/record/17746 Haiman Z. The detectability of high-redshift Lyα emission lines prior to the reionization of the universe. <i>The Astrophysical Journal</i>. 2002;576(1):L1-L4. doi:<a href="https://doi.org/10.1086/343101">10.1086/343101</a> eng info:eu-repo/semantics/altIdentifier/doi/10.1086/343101 info:eu-repo/semantics/altIdentifier/issn/0004-637X info:eu-repo/semantics/altIdentifier/issn/1538-4357 info:eu-repo/semantics/openAccess