z ~ 2.5 - 3 Ionizers in the GOODS-N Field
  We use deep F275W imaging from the $Hubble$ Deep UV Legacy Survey (HDUV) and
G280 grism spectroscopy from $HST$/WFC3, along with new and archival optical
spectra from Keck/DEIMOS, to search for candidate ionizing sources in the
GOODS-N field at z ~ 2.5 - 3. Spectroscopic identification of our UV-selected
sources are 99% complete to F275W = 25.5 in the region of the UV imaging, and
we identify 6 potential ionizing galaxies or AGNs at z ~ 3. By far the
brightest of these is a z = 2.583 AGN that totally dominates the ionizing flux
in the region, with a specific ionizing volume emissivity at $912~ \AA$ of
$\epsilon_{912}$ = $8.3^{27}_{1.4} \times 10^{24}$ erg s$^{-1}$ Hz$^{-1}$
Mpc$^{-3}$. Based on our spectroscopic data, we find four candidates are
contaminated by foreground galaxies at z ~ 0.5 - 0.7. At $\epsilon_{912}$ =
$2.2^{7.2}_{0.4} \times 10^{23}$ erg s$^{-1}$ Hz$^{-1}$ Mpc$^{-3}$, the
remaining candidate galaxy's contribution to the ionizing background lies well
below the flux required to ionize the intergalactic medium at z ~ 2.5 - 3,
consistent with previous observations that show AGNs provide the bulk of the
ionizing background at these redshifts.
