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Using deep narrow-band (NB) imaging and optical spectroscopy from the Kecktelescope and MMT, we identify a sample of 20 emission-line galaxies (ELGs) atz=0.065-0.90 where the weak auroral emission line, [OIII]4363, is detected at>3\sigma. These detections allow us to determine the gas-phase metallicityusing the "direct'' method. With electron temperature measurements and dustattenuation corrections from Balmer decrements, we find that 4 of theselow-mass galaxies are extremely metal-poor with 12+log(O/H) <= 7.65 orone-tenth solar. Our most metal-deficient galaxy has 12+log(O/H) =7.24^{+0.45}_{-0.30} (95% confidence), similar to some of the lowestmetallicity galaxies identified in the local universe. We find that ourgalaxies are all undergoing significant star formation with average specificstar formation rate (SFR) of (100 Myr)^{-1}, and that they have high centralSFR surface densities (average of 0.5 Msun/yr/kpc^2. In addition, more thantwo-thirds of our galaxies have between one and four nearby companions within aprojected radius of 100 kpc, which we find is an excess among star-forminggalaxies at z=0.4-0.85. We also find that the gas-phase metallicities for agiven stellar mass and SFR lie systematically below the local M-Z-(SFR)relation by \approx0.2 dex (2\sigma\ significance). These results are partlydue to selection effects, since galaxies with strong star formation and lowmetallicity are more likely to yield [OIII]4363 detections. Finally, theobserved higher ionization parameter and electron density suggest that they arelower redshift analogs to typical z>1 galaxies.

"Direct" Gas-phase Metallicities, Stellar Properties, and Local Environments of Emission-line Galaxies at Redshift below 0.90