  Recent observations show that the measured rates of star formation in the
early universe are insufficient to produce re-ionization, and therefore,
another source of ionizing photons is required. In this \emph{Letter}, we
examine the possibility that these can be supplied by the fast accretion shocks
formed around the cores of the most massive haloes ($10.5< \log M/M_{\odot} <
12$) on spatial scales of order 1 kpc. We model the detailed physics of these
fast accretion shocks, and apply these to a simple 1-D spherical hydrodynamic
accretion model for baryonic infall in dark matter halos with an Einasto
density distribution. The escape of UV photons from these halos is delayed by
the time taken to reach the critical accretion shock velocity for escape of UV
photons; 220 km s$^{-1}$, and by the time it takes for these photons to ionize
the surrounding baryonic matter in the accretion flow. Assuming that in the
universe at large the baryonic matter tracks the dark matter, we can estimate
the epoch of re-ionization in the case that accretion shocks act alone as the
source of UV photons. We find that 50% of the volume (and 5-8% of the mass) of
the universe can be ionized by $z \sim 7-8$. The UV production rate has an
uncertainty of a factor of about 5 due to uncertainties in the cosmological
parameters controlling the development of large scale structure. Because our
mechanism is a steeply rising function of decreasing redshift, this uncertainty
translates to a re-ionization redshift uncertainty of less than $\pm0.5$. We
also find that, even without including the UV photon production of stars,
re-ionization is essentially complete by $z \sim 5.8$. Thus, fast accretion
shocks can provide an important additional source of ionizing photons in the
early universe.
