  We have recently discovered five Lyman continuum leaking galaxies at z~0.3,
selected for their compactness, intense star-formation, and high [OIII]/[OII]
ratio (Izotov et al. 2016ab). Here we derive their ionizing photon production
efficiency, a fundamental quantity for inferring the number of photons
available to reionize the Universe, for the first time for galaxies with
confirmed strong Lyman continuum escape (fesc~6-13%). We find an ionizing
photon production per unit UV luminosity, which is a factor 2-6 times higher
than the canonical value when reported to their observed UV luminosity. After
correction for extinction this value is close to the canonical value. The
properties of our five Lyman continuum leakers are found to be very similar to
those of the confirmed z=3.218 leaker Ion2 from de Barros et al. (2016) and
very similar to those of typical star-forming galaxies at z>~6. Our results
suggest that UV bright galaxies at high-z such as Lyman break galaxies can be
Lyman continuum leakers and that their contribution to cosmic reionization may
be underestimated.
