Oxygen abundances, SFRs and dust of CFRS galaxies at intermediate redshift

Measurements of the metallicity of galaxies at substantial look-back times is important for tracing the chemical evolution of galaxies and for modeling galaxy properties. Using near-infrared spectroscopy with ISAAC at the VLT and NIRSPEC at Keck, we measured the Hα and [N II]λ 6584 lines of 27 CFRS galaxies at 0.47<z<0.92, an approximately rest-frame-B selected sample of galaxies extending down to about 0.1 L^*. The [O II]λ 3727, Hβ and [O III]λ 5007 lines of these 27 galaxies have been measured from CFHT optical spectra. We have developed a code to simultaneously fit [O II], Hβ, [O III], Hα, and [N II] in terms of the extinction parameter, A_V, ionization parameter, q, and oxygen abundance, [O/H], based on a set of ionization parameter and oxygen abundance diagnostics developed by Kewley & Dopita (2002). Thus, we can determine, for each individual galaxy: a) the extinction, A_V, b) the SFR from the extinction-corrected Hα flux, and c) [O/H], with a precision of, typically, around 0.1 dex. We compare the SFRs, [O/H] and A_V's of these intermediate-redshift galaxies with the properties of local galaxies (e.g., the NFGS sample). Moreover, the metallicity-luminosity relation at intermediate redshift is studied by comparing the oxygen abundances of CFRS galaxies and of other galaxies at intermediate redshift (e.g., emission-line galaxies with faint absolute luminosities found by the Calar Alto Deep Imaging Survey (CADIS)).