Oxygen abundances of zCOSMOS galaxies at z~1.4 based on five lines and
  implications for the fundamental metallicity relation
  A relation between the stellar mass M and the gas-phase metallicity Z of
galaxies, the MZR, is observed up to higher redshifts. It is a matter of
debate, however, if the SFR is a second parameter in the MZR. To explore this
issue at z > 1, we used VLT-SINFONI near-infrared (NIR) spectroscopy of eight
zCOSMOS galaxies at 1.3 < z < 1.4 to measure the strengths of four emission
lines: Hbeta, [OIII]lambda5007, Halpha, and [NII]lambda6584, additional to
[OII]lambda3727 measured from VIMOS. We derive reliable O/H metallicities based
on five lines, and also SFRs from extinction corrected Halpha measurements. We
find that the MZR of these star-forming galaxies at z~1.4 is lower than the
local SDSS MZR by a factor of three to five, a larger change than reported in
the literature using [NII]/Halpha-based metallicities from individual and
stacked spectra. Correcting N2-based O/Hs using recent results by Newman et al.
(2014), also the larger FMOS sample at z~1.4 of Zahid et al. (2014) shows a
similar evolution of the MZR like the zCOSMOS objects. These observations seem
also in agreement with a non-evolving FMR using the physically motivated
formulation of the FMR from Lilly et al. (2013).
