The MOSDEF Survey: A Stellar Mass-SFR-Metallicity Relation Exists at z ∼ 2.3
Abstract
We investigate the nature of the relation among stellar mass, star formation rate, and gas-phase metallicity (the {M}* -SFR-Z relation) at high redshifts using a sample of 260 star-forming galaxies at z ∼ 2.3 from the MOSDEF survey. We present an analysis of the high-redshift {M}* -SFR-Z relation based on several emission-line ratios for the first time. We show that a {M}* -SFR-Z relation clearly exists at z ∼ 2.3. The strength of this relation is similar to predictions from cosmological hydrodynamical simulations. By performing a direct comparison of stacks of z ∼ 0 and z ∼ 2.3 galaxies, we find that z ∼ 2.3 galaxies have ∼0.1 dex lower metallicity at fixed {M}* and SFR. In the context of chemical evolution models, this evolution of the {M}* -SFR-Z relation suggests an increase with redshift of the mass-loading factor at fixed {M}* , as well as a decrease in the metallicity of infalling gas that is likely due to a lower importance of gas recycling relative to accretion from the intergalactic medium at high redshifts. Performing this analysis simultaneously with multiple metallicity-sensitive line ratios allows us to rule out the evolution in physical conditions (e.g., N/O ratio, ionization parameter, and hardness of the ionizing spectrum) at fixed metallicity as the source of the observed trends with redshift and with SFR at fixed {M}* at z ∼ 2.3. While this study highlights the promise of performing high-order tests of chemical evolution models at high redshifts, detailed quantitative comparisons ultimately await a full understanding of the evolution of metallicity calibrations with redshift.
Based on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and NASA, and was made possible by the generous financial support of the W. M. Keck Foundation.- Publication:
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The Astrophysical Journal
- Pub Date:
- May 2018
- DOI:
- 10.3847/1538-4357/aabcbd
- arXiv:
- arXiv:1711.00224
- Bibcode:
- 2018ApJ...858...99S
- Keywords:
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- galaxies: abundances;
- galaxies: high-redshift;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- 19 pages, 8 figures, accepted to ApJ