Rate with which ionizing photons reach the intergalactic medium. Panels a, b, and c: rate for H I-ionizing photons and panels d, e, and f: for He II-ionizing photons. Left column: results for our standard model, middle column: for our high-f_esc model, and right column: for our low-f_esc model (see Table 1). We show the contribution from stripped stars in dark blue, from massive stars in light blue, and from AGN in brown. The extent of the colored regions represents the spread caused by metallicity variations. The results for the combination model (see Table 1) are the same as in the high-f_esc model for the stripped stars and the same as in the low-f_esc model for the massive stars.