The First Measurement of Star Formation Rates in Damped Lyman alpha
Systems

Abstract:  Damped Lyman alpha Absorption systems (DLAs) contain most of
the neutral hydrogen in the high-redshift universe and are the likely
progenitors of typical galaxies like the Milky Way.  However, it is not
yet clear whether DLAs are coincident with the Lyman break galaxies
(LBGs) detected in emission or represent a separate population of low-mass
protogalaxies.  The metallicity of the universe as probed by DLAs does
not evolve from z=4 to z=2, and dust extinction does not appear to bias
these measurements significantly.  I will present the first measurement
of DLA star formation rates (SFR):  although the inferred SFR/area of DLAs
is much lower than that of LBGs, they contribute a comparable amount to
the cosmic star formation history (Madau plot).  Constraints from the
integrated background radiation are used to show that DLA interstellar
media cannot be comprised of pure Warm Neutral Medium.  The measured star
formation rates predict metallicities for DLAs at z>2 far in excess of
those observed, and I will discuss possible resolutions of this conflict.