Program: GN-2016B-FT-11

We propose Gemini GNIRS H-band spectra of to obtain [N II]/Halpha and [S II]/[S II] ratios in two extremely bright lensed galaxies at z=1.4 This program directly supports an approved Cycle 23 HST WFC3 grism, which will obtain the full suite of rest-frame optical diagnostics. The low spectral resolution of the WFC3 grism means that HST cannot measure these line ratios, which creates degeneracies that will impact the precise measurements of metallicity, ionization parameter, excitation, star formation rate, and extiction. Fortunately, GNIRS on Gemini can quickly measure these line ratios, and thus substantially improve the total science return from the HST program.