First Light II: Emission Line Extinction, Population III Stars, and
  X-ray Binaries
  We produce synthetic spectra and observations for metal-free stellar
populations and high mass X-ray binaries in the Renaissance Simulations at a
redshift of 15. We extend our methodology from the first paper in the series by
modelling the production and extinction of emission lines throughout a dusty
and metal-enriched interstellar and circum-galactic media extracted from the
simulation, using a Monte Carlo calculation. To capture the impact of
high-energy photons, we include all frequencies from hard X-ray to far infrared
with enough frequency resolution to discern line emission and absorption
profiles. The most common lines in our sample in order of their rate of
occurrence are Ly$\alpha$, the C IV $\lambda\lambda1548,1551$ doublet,
H-$\alpha$, and the Ca II $\lambda\lambda\lambda8498,8542,8662$ triplet. The
best scenario for a direct observation of a metal-free stellar population is a
merger between two Population III galaxies. In mergers between metal-enriched
and metal-free stellar populations, some characteristics may be inferred
indirectly. Single Population III galaxies are too dim to be observed
photometrically at $z = 15$. Ly$\alpha$ emission is discernible by $JWST$ as an
increase in $\rm{J_{200w} - J_{277w}}$ colour off the intrinsic stellar tracks.
Observations of metal-free stars will be difficult, though not impossible, with
the next generation of space telescopes.
