Flux sensitivity requirements for the detection of Lyman continuum
  radiation drop-ins from star-forming galaxies below redshifts of 3
  Flux estimates for ionizing radiation escaping from star-forming galaxies
with characteristic UV luminosities ($L^{*}_{1500(1+z)}$) derived from GALEX
and the VIMOS-VLT Deep Survey, are presented as a function of redshift and
assumed escape fraction. These estimates offer guidance to the design of
instrumentation and observing strategies, be they spectroscopic or photometric,
attempting to detect LyC escaping star-forming galaxies for redshifts $ z < 3$.
Examples are given that relate the absolution escape fraction ($f^{e}_{LyC}$)
of ionizing photons, integrated over the entire extreme UV (EUV) bandpass, to
the relative escape fraction ($f^{e}_{900}$) observed just shortward of the
ionization edge at 911.8 \AA\ as a function of HI, HeI, and HeII column
densities. We find that for $\log{N_{HI}(cm^{-2})} \gtrsim 17.0$ $f^{e}_{LyC}$
is significantly greater than $f^{e}_{900}$. Detection of LyC "drop-ins" in the
rest-frame EUV will provide enhanced fidelity to determinations of the
integrated fraction of ionizing photons $f^{e}_{LyC}$ that escape star-forming
galaxies and contribute to the meta-galactic ionizing background.
