Detection of Lyman Continuum from 3.0 < z < 3.5 Galaxies in the HETDEX
  Survey
  Questions as to what drove the bulk reionization of the Universe, how that
reionization proceeded, and how the hard ionizing radiation reached the
intergalactic medium remain open and debated. Observations probing that epoch
are severely hampered by the increasing amounts of neutral gas with increasing
redshift, so a small, but growing number of experiments are targeting star
forming galaxies ($z\sim3$) as proxies. However, these studies, while providing
fantastic detail, are time intensive, contain relatively few targets, and can
suffer from selection biases. As a complementary alternative, we investigate
whether stacking the already vast (and growing) numbers of low-resolution
($\Delta \lambda / \lambda = 800$) Lyman-$\alpha$ Emitting (LAE) galaxy spectra
from the Hobby-Eberly Telescope Dark Energy Experiment (HETDEX) can be used to
measure ionizing photons (restframe 880-910\AA) escaping their galaxy hosts. As
a blind survey, HETDEX avoids the biases from continuum selected galaxies and
its planned 540 square degree coverage promotes the statistical power of large
numbers. In this paper, we confirm the feasibility of Lyman continuum detection
by carefully selecting a sample of \lyccount\ high redshift ($z\sim$3) LAEs
from a subset of HETDEX observations, stacking their spectra and measuring a
$\gtrsim$3$\sigma$ detection of $0.10 \mu$Jy restframe Lyman continuum
emission, uncorrected for attenuation in the intergalactic medium, over the
full sample stack ($3.0 < z < 3.5$ and $-22.0 \lesssim M_{\text{UV}} \lesssim
-19.0$).
