The Metallicity of 0.5 < [CLC][ITAL]z[/ITAL][/CLC] < 1 Field Galaxies

We have measured the emission line ratios in a sample of 34 CFRS star-forminggalaxies with redshifts between 0.5 < z < 1.0, and computed their metallicitiesby means of the empirically-calibrated R_23 metallicity estimator introduced byPagel et al. (1979). The current analysis concentrates on the 15 galaxies withL_Hbeta > 1.2x10^41 erg s-1. Although our results can only be regarded aspreliminary until near-IR spectroscopy of Halpha and [NII]6583 are available,the metallicities of these galaxies appear to be remarkably similar to those oflocal galaxies selected in the same way, and there appears to have been littlechange in the relationship between metallicity and line- andcontinuum-luminosity from z~1 to today. At this stage our results do notsupport the idea that these galaxies, known to be generally small and withlate-type morphologies, are dwarf galaxies brightened by large bursts ofstar-formation, as had been suggested from previous studies. Rather, ourfindings are more consistent with a picture in which these systems are theprogenitors of today's massive metal-rich galaxies.Comment: ApJ Letters, accepted for publicatio