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

Abstract 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, x HI , using the Lyman α transmission statistics of high-redshift ( z ≳ 6) sources. We find that only tens of bright quasar spectra could distinguish between x HI ∼ 1 and x HI ≲ 10 −2 . A rudimentary application of such a technique on quasar SDSS J1030+0524 has yielded compelling evidence of a large neutral fraction ( x HI ≳ 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.