| Measuring oxygen-to-hydrogen abundance ratio as a metallicity tracer in galaxies has been widely used for local HII regions and star forming galaxies. Towards high redshift, these efforts face difficulties since the emission lines used, mainly the auroral [OIII]4363 for electron temperature with the direct method, are shifted to the IR and they lack good signal-to-noise. We measure, with high precision, the oxygen abundance of about ~15 local analogs of galaxies at redshift ~2.3 and study the relations with the strong emission line ratios. We used optical spectra of the analogs gathered with the Magellan/Echelle spectrograph at the 6.5m Blade Telescope in Las Campanas Observatory. In addition to the optical, we count with IR spectra for some of these analogs taken with the FIRE spectrograph at the same observatory. Using optical and infrared emission lines we can certainly diagnose the nature of the ionization of the gas present in these galaxies, exploring the differences between metallicity calibrations and infer their behavior in the high redshift universe. |
