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FUSE spectra of star-forming regions in nearby galaxies are compared tocomposite spectra of Lyman-break galaxies (LBGs), binned by strength of Lymanalpha emission and by mid-UV luminosity. Several far-UV spectral features,including lines dominated by stellar wind and by photospheric components, arevery sensitive to stellar abundances. Their measurement in Lyman-break galaxiesis compromised by the strong interstellar absorption features, allowing in somecases only upper limits. The derived C and N abundances in the LBGs are nohigher than half solar (scaled to oxygen abundance for comparison withemission-line analyses), independent of the strength of Lyman alpha emission. PV absorption indicates abundances as low as 0.1 solar, with an upper limit near0.4 solar in the reddest and weakest-emission galaxies. Unresolved interstellarabsorption components would further lower the derived abundances. Trends ofline strength, and derived abundances, are stronger with mid-UV luminosity thanwith Lyman-alpha strength. H2 absorption in the Lyman and Werner bands is veryweak in the LBGs. Template H2 absorption spectra convolved to appropriateresolution show that strict upper limits N(H2)< 10^18 cm^-2 apply in all cases,with more stringent values appropriate for the stronger-emission composites andfor mixes of H2 level populations like those on Milky Way sight lines. Sincethe UV-bright regions are likely to be widespread in these galaxies, theseresults rule out massive diffuse reservoirs of H2, and suggest that thedust/gas ratio is already fairly large at z~3.Comment: Astron J., in press (June 2006

Stellar Abundances and Molecular Hydrogen in High-Redshift Galaxies: The Far-Ultraviolet View