The z~2 mass-metallicity relation from lensed galaxies
Abstract
We propose to study the evolving relationship between stellar mass and gas metallicity at 0.7<z<2.5, from a sample of 40 lensed galaxies. Eighteen galaxies already have [N II]/H(alpha) metallicities from Keck and Magellan. Here, we propose Gemini-N/GNIRS spectroscopy of 22 lensed galaxies, to make a total sample 4× larger than what has been published at these redshifts and low stellar masses. For all 22 targets the GNIRS spectra will measure the [N II]/H(alpha) metallicity diagnostic; for 8 targets they will measure the R23 metallicity diagnostic; for 13 targets they will cover the [O II] 4363 Ametallicity diagnostic. Seven targets will have all three diagnostics covered. Lensed galaxies uniquely probe the low-mass end of the mass- metallicity relation. All 40 galaxies in the sample have Spitzer/IRAC to measure stellar mass, and 4-band HST images to measure stellar populations and properties of star-forming regions. GNIRS spectra will address three questions about the evolution of galactic metals: 1. How does metallicity evolve with redshift, as a function of stellar mass? 2. Do metallicity diagnostics evolve with redshift? 3. Do the properties of star-forming regions depend on metallicity?
- Publication:
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NOAO Proposal
- Pub Date:
- February 2014
- Bibcode:
- 2014noao.prop..311R