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Title: Separate Ways: The Mass–Metallicity Relation Does Not Strongly Correlate with Star Formation Rate in SDSS-IV MaNGA Galaxies

Abstract

We present the integrated stellar mass–metallicity relation (MZR) for more than 1700 galaxies included in the integral field area SDSS-IV MaNGA survey. The spatially resolved data allow us to determine the metallicity at the same physical scale (effective radius, R {sub eff}) using a heterogeneous set of 10 abundance calibrators. In addition to scale factors, the shape of the MZR is similar for all calibrators, consistent with those reported previously using single-fiber and integral field spectroscopy. We compare the residuals of this relation against the star formation rate (SFR) and specific SFR (sSFR). We do not find a strong secondary relation of the MZR with either SFR or sSFR for any of the calibrators, in contrast with previous single-fiber spectroscopic studies. Our results agree with a scenario in which metal enrichment happens at local scales, with global outflows playing a secondary role in shaping the chemistry of galaxies and cold-gas inflows regulating the stellar formation.

Authors:
;  [1];  [2];  [3];
  1. Department of Physics and Astronomy, Johns Hopkins University, Bloomberg Center, 3400 N. Charles St., Baltimore, MD 21218 (United States)
  2. Instituto de Astronomía, Universidad Nacional Autónoma de México, A.P. 70-264, 04510 México, D.F., México (Mexico)
  3. Observatories of the Carnegie Institution for Science, 813 Santa Barbara St, Pasadena, CA 91101 (United States)
Publication Date:
OSTI Identifier:
22663346
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 844; Journal Issue: 1; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABUNDANCE; COMPARATIVE EVALUATIONS; GALAXIES; MASS; METALLICITY; METALS; SPECTROSCOPY; STARS

Citation Formats

Barrera-Ballesteros, J. K., Heckman, T., Sánchez, S. F., Blanc, G. A., E-mail: jbarrer3@jhu.edu, and Collaboration: MaNGA Team. Separate Ways: The Mass–Metallicity Relation Does Not Strongly Correlate with Star Formation Rate in SDSS-IV MaNGA Galaxies. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA7AA9.
Barrera-Ballesteros, J. K., Heckman, T., Sánchez, S. F., Blanc, G. A., E-mail: jbarrer3@jhu.edu, & Collaboration: MaNGA Team. Separate Ways: The Mass–Metallicity Relation Does Not Strongly Correlate with Star Formation Rate in SDSS-IV MaNGA Galaxies. United States. doi:10.3847/1538-4357/AA7AA9.
Barrera-Ballesteros, J. K., Heckman, T., Sánchez, S. F., Blanc, G. A., E-mail: jbarrer3@jhu.edu, and Collaboration: MaNGA Team. Thu . "Separate Ways: The Mass–Metallicity Relation Does Not Strongly Correlate with Star Formation Rate in SDSS-IV MaNGA Galaxies". United States. doi:10.3847/1538-4357/AA7AA9.
@article{osti_22663346,
title = {Separate Ways: The Mass–Metallicity Relation Does Not Strongly Correlate with Star Formation Rate in SDSS-IV MaNGA Galaxies},
author = {Barrera-Ballesteros, J. K. and Heckman, T. and Sánchez, S. F. and Blanc, G. A., E-mail: jbarrer3@jhu.edu and Collaboration: MaNGA Team},
abstractNote = {We present the integrated stellar mass–metallicity relation (MZR) for more than 1700 galaxies included in the integral field area SDSS-IV MaNGA survey. The spatially resolved data allow us to determine the metallicity at the same physical scale (effective radius, R {sub eff}) using a heterogeneous set of 10 abundance calibrators. In addition to scale factors, the shape of the MZR is similar for all calibrators, consistent with those reported previously using single-fiber and integral field spectroscopy. We compare the residuals of this relation against the star formation rate (SFR) and specific SFR (sSFR). We do not find a strong secondary relation of the MZR with either SFR or sSFR for any of the calibrators, in contrast with previous single-fiber spectroscopic studies. Our results agree with a scenario in which metal enrichment happens at local scales, with global outflows playing a secondary role in shaping the chemistry of galaxies and cold-gas inflows regulating the stellar formation.},
doi = {10.3847/1538-4357/AA7AA9},
journal = {Astrophysical Journal},
number = 1,
volume = 844,
place = {United States},
year = {Thu Jul 20 00:00:00 EDT 2017},
month = {Thu Jul 20 00:00:00 EDT 2017}
}
  • A very simple physical model of galaxies is one in which the formation of stars is instantaneously regulated by the mass of gas in a reservoir with mass loss scaling with the star-formation rate (SFR). This model links together three different aspects of the evolving galaxy population: (1) the cosmic time evolution of the specific star-formation rate (sSFR) relative to the growth of halos, (2) the gas-phase metallicities across the galaxy population and over cosmic time, and (3) the ratio of the stellar to dark matter mass of halos. The gas regulator is defined by the gas consumption timescale ({epsilon}{supmore » -1}) and the mass loading {lambda} of the wind outflow {lambda}{center_dot}SFR. The simplest regulator, in which {epsilon} and {lambda} are constant, sets the sSFR equal to exactly the specific accretion rate of the galaxy; more realistic situations lead to an sSFR that is perturbed from this precise relation. Because the gas consumption timescale is shorter than the timescale on which the system evolves, the metallicity Z is set primarily by the instantaneous operation of the regulator system rather than by the past history of the system. The metallicity of the gas reservoir depends on {epsilon}, {lambda}, and sSFR, and the regulator system therefore naturally produces a Z(m{sub star}, SFR) relation if {epsilon} and {lambda} depend on the stellar mass m{sub star}. Furthermore, this relation will be the same at all epochs unless the parameters {epsilon} and {lambda} themselves change with time. A so-called fundamental metallicity relation is naturally produced by these conditions. The overall mass-metallicity relation Z(m{sub star}) directly provides the fraction f{sub star}(m{sub star}) of incoming baryons that are being transformed into stars. The observed Z(m{sub star}) relation of Sloan Digital Sky Survey (SDSS) galaxies implies a strong dependence of stellar mass on halo mass that reconciles the different faint-end slopes of the stellar and halo mass functions in standard {Lambda}CDM models. The observed relation also boosts the sSFR relative to the specific accretion rate and produces a different dependence on mass, both of which are observed. The derived Z(m{sub star}, SFR) relation for the regulator system is fit to published Z(m{sub star}, SFR) data for the SDSS galaxy population, yielding {epsilon} and {lambda} as functions of m{sub star}. The fitted {epsilon} is consistent with observed molecular gas-depletion timescales in galaxies (allowing for the extra atomic gas), while the fitted {lambda} is also reasonable. The gas-regulator model also successfully reproduces the Z(m{sub star}) metallicities of star-forming galaxies at z {approx} 2. One consequence of this analysis is that it suggests that the m{sub star}-m{sub halo} relation is established by baryonic processes operating within galaxies, and that a significant fraction (40%) of baryons coming into the halos are being processed through the galaxies. This fraction may be more or less constant. The success of the gas-regulator model in simultaneously explaining many diverse observed relations over the 0 < z < 2 interval suggests that the evolution of galaxies is governed by simple physics that form the basis for this model.« less
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