{
  "id": "1408.2521",
  "version": "v2",
  "published": "2014-08-11T20:00:05.000Z",
  "updated": "2014-11-24T19:08:15.000Z",
  "title": "The MOSDEF Survey: Mass, Metallicity, and Star-formation Rate at z~2.3",
  "authors": [
    "Ryan L. Sanders",
    "Alice E. Shapley",
    "Mariska Kriek",
    "Naveen A. Reddy",
    "William R. Freeman",
    "Alison L. Coil",
    "Brian Siana",
    "Bahram Mobasher",
    "Irene Shivaei",
    "Sedona H. Price",
    "Laura de Groot"
  ],
  "comment": "12 pages, 6 figures, accepted for publication in the Astrophysical Journal (ApJ)",
  "categories": [
    "astro-ph.GA"
  ],
  "abstract": "We present results on the z~2.3 mass-metallicity relation (MZR) using early observations from the MOSFIRE Deep Evolution Field (MOSDEF) survey. We use an initial sample of 87 star-forming galaxies with spectroscopic coverage of H\\beta, [OIII]\\lambda 5007, H\\alpha, and [NII]\\lambda 6584 rest-frame optical emission lines, and estimate the gas-phase oxygen abundance based on the N2 and O3N2 strong-line indicators. We find a positive correlation between stellar mass and metallicity among individual z~2.3 galaxies using both the N2 and O3N2 indicators. We also measure the emission-line ratios and corresponding oxygen abundances for composite spectra in bins of stellar mass. Among composite spectra, we find a monotonic increase in metallicity with increasing stellar mass, offset ~0.15-0.3 dex below the local MZR. When the sample is divided at the median star-formation rate (SFR), we do not observe significant SFR dependence of the z~2.3 MZR among either individual galaxies or composite spectra. We furthermore find that z~2.3 galaxies have metallicities ~0.1 dex lower at a given stellar mass and SFR than is observed locally. This offset suggests that high-redshift galaxies do not fall on the local \"fundamental metallicity relation\" among stellar mass, metallicity, and SFR, and may provide evidence of a phase of galaxy growth in which the gas reservoir is built up due to inflow rates that are higher than star-formation and outflow rates. However, robust conclusions regarding the gas-phase oxygen abundances of high-redshift galaxies await a systematic reappraisal of the application of locally calibrated metallicity indicators at high redshift.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2014-08-11T20:00:05.000Z",
      "comment": "10 pages, 6 figures, submitted to ApJ",
      "journal": null,
      "doi": null
    },
    {
      "version": "v2",
      "updated": "2014-11-24T19:08:15.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "metallicity",
      "star-formation rate",
      "stellar mass",
      "mosdef survey",
      "gas-phase oxygen abundance"
    ],
    "tags": [
      "journal article"
    ],
    "publication": {
      "doi": "10.1088/0004-637X/799/2/138",
      "journal": "The Astrophysical Journal",
      "year": 2015,
      "month": "Feb",
      "volume": 799,
      "number": 2,
      "pages": 138
    },
    "note": {
      "typesetting": "TeX",
      "pages": 12,
      "language": "en",
      "license": "arXiv",
      "status": "editable",
      "adsabs": "2015ApJ...799..138S"
    }
  }
}