Brian Siana


" Were Galaxies Able to Reionize the Universe  Measuring the Lyman Continuum Escape Fraction With Hubble"


For a few hundred million years after recombination, the universe was
completely neutral but, by z=6, ionizing radiation from galaxies was
able to reionize the hydrogen in the intergalactic medium. Despite the
importance of this reionization on galaxy formation, it is not well
understood how large fractions of ionizing photons are able to escape
from star-forming galaxies.  We have conducted several large surveys
with the Hubble Space Telescope to directly measure the ionizing
emissivity of high redshift galaxies.  These include new resolved
images of escaping ionizing radiation from galaxies at z=3.  I will
discuss the results of these surveys, and their implications for
models of reionization.