ISM excitation and metallicity of star-forming galaxies at z~3.3 from near-IR spectroscopy

Understand

We study the relationship between stellar mass, star formation rate (SFR),ionization state, and gas-phase metallicity for a sample of 41 normal star-forming galaxies at $3 \lesssim z \lesssim 3.7$.

• The gas-phase oxygen abundance, ionization parameter, and electron density of ionized gas are derived from rest-frame optical strong emission lines measured on near-infrared spectra obtained with Keck/MOSFIRE.
• We remove the effect of these strong emission lines in the broad-band fluxes to compute stellar masses via spectral energy distribution fitting, while the SFR is derived from the dust-corrected ultraviolet luminosity.
• The ionization parameter is weakly correlated with the specific SFR, but otherwise the ionization parameter and electron density do not correlate with other global galaxy properties such as stellar mass, SFR, and metallicity.