Probing reionization with the cosmological proximity effect and high-redshift supernovae rates

We develop and assess the potential of several powerful techniques, designed to investigate the details of reionization. First, we present a procedure to probe the neutral fraction, xHI, using the Lyman α transmission statistics of high-redshift (z ≳ 6) sources. We find that only tens of bright quasar spectra could distinguish between xHI ∼ 1 and xHI ≲ 10-2. A rudimentary application of such a technique on quasar SDSS J1030+0524 has yielded compelling evidence of a large neutral fraction (xHI ≳ 0.2) at z ∼ 6. We also generate the observable, high-z supernovae (SNe) rates and quantify the prospects of detecting the suppression of star-formation in low-mass galaxies at reionization from such SNe rates, specifically from those obtainable from the James Webb Space Telescope (JWST). Our analysis suggests that searches for SNe could yield thousands of SNe per unit redshift at z ∼ 6, and be a valuable tool at studying reionization features and feedback effects out to z ≲ 13. © 2005 Elsevier B.V. All rights reserved.