Intensity mapping of molecular gas during cosmic reionization
  I present a simple calculation of the expected mean CO brightness temperature
from the large scale distribution of galaxies during cosmic reionization. The
calculation is based on the cosmic star formation rate density required to
reionize, and keep ionized, the intergalactic medium, and uses standard
relationships between star formation rate, IR luminosity, and CO luminosity
derived for star forming galaxies over a wide range in redshift. I find that
the mean CO brightness temperature resulting from the galaxies that could
reionize the Universe at $z = 8$ is $T_B \sim 1.1 (C/5) (f_{esc}/0.1)^{-1}
\mu$K, where $f_{esc}$ is the escape fraction of ionizing photons from the
first galaxies, and $C$ is the IGM clumping factor. Intensity mapping of the CO
emission from the large scale structure of the star forming galaxies during
cosmic reionization on scales of order $10^2$ to 10$^3$ deg$^2$, in combination
with HI 21cm imaging of the neutral IGM, will provide a comprehensive study of
the earliest epoch of galaxy formation.
