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Stellar Mass--Gas-phase Metallicity Relation at 0.5 ≤ z ≤ 0.7: A Power Law with Increasing Scatter toward the Low-mass Regime

Guo, Yicheng and Koo, David C. and Lu, Yu and Forbes, John C. and Rafelski, Marc and Trump, Jonathan R. and Amorín, Ricardo and Barro, Guillermo and Davé, Romeel and Faber, S. M. and Hathi, Nimish P. and Yesuf, Hassen and Cooper, Michael C. and Dekel, Avishai and Guhathakurta, Puragra and Kirby, Evan N. and Koekemoer, Anton M. and Pérez-González, Pablo G. and Lin, Lihwai and Newman, Jeffery A. and Primack, Joel R. and Rosario, David J. and Willmer, Christopher N. A. and Yan, Renbin (2016) Stellar Mass--Gas-phase Metallicity Relation at 0.5 ≤ z ≤ 0.7: A Power Law with Increasing Scatter toward the Low-mass Regime. Astrophysical Journal, 822 (2). Art. No. 103. ISSN 0004-637X.

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We present the stellar mass (M_*)–gas-phase metallicity relation (MZR) and its scatter at intermediate redshifts (0.5 ⩽ z ⩽ 0.7) for 1381 field galaxies collected from deep spectroscopic surveys. The star formation rate (SFR) and color at a given M_* of this magnitude-limited (R ≾ 24 AB) sample are representative of normal star-forming galaxies. For masses below 10^9 M_☉, our sample of 237 galaxies is ~10 times larger than those in previous studies beyond the local universe. This huge gain in sample size enables superior constraints on the MZR and its scatter in the low-mass regime. We find a power-law MZR at 10^8 M_☉ < M_* < 10^(11)M_☉: 12 + log(O/H)=(5.83 ± 0.19)+(0.30 ± 0.02)log(M_*/M_☉). At 10^9 M_☉ < M_* < 10^(10.5) M_☉, our MZR shows agreement with others measured at similar redshifts in the literature. Our power-law slope is, however, shallower than the extrapolation of the MZRs of others to masses below 10^9 M_☉. The SFR dependence of the MZR in our sample is weaker than that found for local galaxies (known as the fundamental metallicity relation). Compared to a variety of theoretical models, the slope of our MZR for low-mass galaxies agrees well with predictions incorporating supernova energy-driven winds. Being robust against currently uncertain metallicity calibrations, the scatter of the MZR serves as a powerful diagnostic of the stochastic history of gas accretion, gas recycling, and star formation of low-mass galaxies. Our major result is that the scatter of our MZR increases as M_* decreases. Our result implies that either the scatter of the baryonic accretion rate (σ_Ṁ) or the scatter of the M_* M_(halo) relation (σ_(SHMR)) increases as M_* decreases. Moreover, our measure of scatter at z = 0.7 appears consistent with that found for local galaxies. This lack of redshift evolution constrains models of galaxy evolution to have both σ_Ṁ and σ_(SHMR) remain unchanged from z = 0.7 to z = 0.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Guo, Yicheng0000-0003-2775-2002
Koo, David C.0000-0003-3385-6799
Lu, Yu0000-0003-2691-1622
Rafelski, Marc0000-0002-9946-4731
Barro, Guillermo0000-0001-6813-875X
Faber, S. M.0000-0003-4996-214X
Hathi, Nimish P.0000-0001-6145-5090
Cooper, Michael C.0000-0003-1371-6019
Dekel, Avishai0000-0003-4174-0374
Guhathakurta, Puragra0000-0001-8867-4234
Kirby, Evan N.0000-0001-6196-5162
Koekemoer, Anton M.0000-0002-6610-2048
Pérez-González, Pablo G.0000-0003-4528-5639
Lin, Lihwai0000-0001-7218-7407
Newman, Jeffery A.0000-0001-8684-2222
Primack, Joel R.0000-0001-5091-5098
Additional Information:© 2016 The American Astronomical Society. Received 2015 June 26; accepted 2016 March 14; published 2016 May 11. We thank the anonymous referee for constructive comments that improve this article. We thank Aldo Rodriguez-Puebla for useful discussions. Several authors from UCSC acknowledge support from NSF grant AST-0808133. Support for Program HST-GO-12060 and HST-AR-13891 was provided by NASA through a grant from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Incorporated, under NASA contract NAS 5-26555. M.R. also acknowledges support from an appointment to the NASA Postdoctoral Program at Goddard Space Flight Center. J.F. is supported by HST-AR-13909. J.R.T. acknowledges support from NASA through Hubble Fellowship grant #51330 awarded by the Space Telescope Science Institute. A.D. is supported by ISF grant 24/12, by the I-CORE Program of the PBC ISF grant 1829/12, and by NSF grant AST-1405962. P.G.P.G. acknowledges support from Spanish MINECO grant AYA2012-31277. Facility: Keck (DEIMOS).
Funding AgencyGrant Number
NASANAS 5-26555
NASA Postdoctoral ProgramUNSPECIFIED
NASA Hubble Fellowship51330
Israel Science Foundation24/12
Israel Science Foundation1829/12
Ministerio de Economía y Competitividad (MINECO)AYA2012-31277
Subject Keywords:galaxies: abundances; galaxies: dwarf; galaxies: evolution; galaxies: formation; galaxies: fundamental parameters; galaxies: ISM
Issue or Number:2
Record Number:CaltechAUTHORS:20160701-104542973
Persistent URL:
Official Citation:Yicheng Guo et al 2016 ApJ 822 103
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:68809
Deposited By: Ruth Sustaita
Deposited On:01 Jul 2016 19:29
Last Modified:09 Mar 2020 13:19

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