SDSS-IV MaNGA: The impact of diffuse ionized gas on emission-line ratios, interpretation of diagnostic diagrams and gas metallicity measurements

Kai Zhang; Renbin Yan; Kevin Bundy; Matthew Bershady; L. Matthew Haffner; René Walterbos; Roberto Maiolino; Christy Tremonti; Daniel Thomas; Niv Drory; Amy Jones; Francesco Belfiore; Sebastian F. Sánchez; Aleksandar M. Diamond-Stanic; Dmitry Bizyaev; Christian Nitschelm; Brett Andrews; Jon Brinkmann; Joel R. Brownstein; Edmond Cheung; Cheng Li; David R. Law; Alexandre Roman-Lopes; Daniel Oravetz; Kaike Pan; Thaisa Storchi Bergmann; Audrey Simmons

doi:10.1093/mnras/stw3308

SDSS-IV MaNGA: The impact of diffuse ionized gas on emission-line ratios, interpretation of diagnostic diagrams and gas metallicity measurements

Kai Zhang, Renbin Yan, Kevin Bundy, Matthew Bershady, L. Matthew Haffner, René Walterbos, Roberto Maiolino, Christy Tremonti, Daniel Thomas, Niv Drory, Amy Jones, Francesco Belfiore, Sebastian F. Sánchez, Aleksandar M. Diamond-Stanic, Dmitry Bizyaev, Christian Nitschelm, Brett Andrews, Jon Brinkmann, Joel R. Brownstein, Edmond CheungCheng Li, David R. Law, Alexandre Roman-Lopes, Daniel Oravetz, Kaike Pan, Thaisa Storchi Bergmann, Audrey Simmons

Physics And Astronomy

Research output: Contribution to journal › Article › peer-review

139 Scopus citations

Abstract

Diffuse ionized gas (DIG) is prevalent in star-forming galaxies. Using a sample of 365 nearly face-on star-forming galaxies observed byMapping Nearby Galaxies at APO, we demonstrate how DIG in star-forming galaxies impacts the measurements of emission-line ratios, hence the interpretation of diagnostic diagrams and gas-phase metallicity measurements. At fixed metallicity, DIG-dominated low Σ_Hα regions display enhanced [S II]/Hα, [NII]/Hα, [OII]/Hβ and [O I]/Hα. The gradients in these line ratios are determined by metallicity gradients and Σ_Hα. In line ratio diagnostic diagrams, contamination by DIG moves HII regions towards composite or low-ionization nuclear emission-line region (LI(N)ER)-like regions. A harder ionizing spectrum is needed to explain DIG line ratios. Leaky HII region models can only shift line ratios slightly relative toHII region models, and thus fail to explain the composite/LI(N)ER line ratios displayed by DIG. Our result favours ionization by evolved stars as a major ionization source forDIG with LI(N)ER-like emission. DIG can significantly bias themeasurement of gas metallicity and metallicity gradients derived using strong-line methods. Metallicities derived using N2O2 are optimal because they exhibit the smallest bias and error. Using O3N2, R₂₃, N2 = [N II]/Hα and N2S2Hα to derive metallicities introduces bias in the derived metallicity gradients as large as the gradient itself. The strong-line method of Blanc et al. (IZI hereafter) cannot be applied to DIG to get an accurate metallicity because it currently contains only HII region models that fail to describe the DIG.

Original language	English
Pages (from-to)	3217-3243
Number of pages	27
Journal	Monthly Notices of the Royal Astronomical Society
Volume	466
Issue number	3
DOIs	https://doi.org/10.1093/mnras/stw3308
State	Published - Apr 21 2017

Bibliographical note

Funding Information:
KB is supported by World Premier International Research Center Initiative (WPI Initiative), MEXT, Japan and by JSPS KAKENHI Grant Number 15K17603. MAB acknowledges support from NSF AST-1517006. RM acknowledge support by the Science and Technology Facilities Council (STFC) and the ERC Advanced Grant 695671 'QUENCH'. C.A.T. acknowledges support from National Science Foundation of the United States grant no. 1412287. DB was supported by grant RSF 14-50-00043. AD acknowledges support from The Grainger Foundation. Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the US Department of Energy Office of Science and the Participating Institutions. SDSS-IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS web site is www.sdss.org. SDSS-IV is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration including the Brazilian Participation Group, the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, the French Participation Group, Harvard-Smithsonian Center for Astrophysics, Instituto de Astrofísica de Canarias, The Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/ University of Tokyo, Lawrence Berkeley National Laboratory, Leibniz Institut für Astrophysik Potsdam (AIP), Max-Planck-Institut für Astronomie (MPIA Heidelberg),Max-Planck-Institut für Astrophysik (MPA Garching),Max-Planck-Institut für Extraterrestrische Physik (MPE), National Astronomical Observatory of China, New Mexico State University, New York University, University of Notre Dame, Observatrio Nacional/ MCTI, The Ohio State University, Pennsylvania State University, Shanghai Astronomical Observatory, United Kingdom Participation Group, Universidad Nacional Autónoma de México, University of Arizona, University of Colorado Boulder, University of Oxford, University of Portsmouth, University of Utah, University of Virginia, University of Washington, University of Wisconsin, Vanderbilt University and Yale University.

Publisher Copyright:
© 2016 The Authors.

Keywords

Galaxies: ISM
Galaxies: abundances
Galaxies: active
Galaxies: evolution
Galaxies: fundamental parameters

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

Access to Document

10.1093/mnras/stw3308

Cite this

Zhang, K., Yan, R., Bundy, K., Bershady, M., Matthew Haffner, L., Walterbos, R., Maiolino, R., Tremonti, C., Thomas, D., Drory, N., Jones, A., Belfiore, F., Sánchez, S. F., Diamond-Stanic, A. M., Bizyaev, D., Nitschelm, C., Andrews, B., Brinkmann, J., Brownstein, J. R., ... Simmons, A. (2017). SDSS-IV MaNGA: The impact of diffuse ionized gas on emission-line ratios, interpretation of diagnostic diagrams and gas metallicity measurements. Monthly Notices of the Royal Astronomical Society, 466(3), 3217-3243. https://doi.org/10.1093/mnras/stw3308

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title = "SDSS-IV MaNGA: The impact of diffuse ionized gas on emission-line ratios, interpretation of diagnostic diagrams and gas metallicity measurements",

abstract = "Diffuse ionized gas (DIG) is prevalent in star-forming galaxies. Using a sample of 365 nearly face-on star-forming galaxies observed byMapping Nearby Galaxies at APO, we demonstrate how DIG in star-forming galaxies impacts the measurements of emission-line ratios, hence the interpretation of diagnostic diagrams and gas-phase metallicity measurements. At fixed metallicity, DIG-dominated low ΣHα regions display enhanced [S II]/Hα, [NII]/Hα, [OII]/Hβ and [O I]/Hα. The gradients in these line ratios are determined by metallicity gradients and ΣHα. In line ratio diagnostic diagrams, contamination by DIG moves HII regions towards composite or low-ionization nuclear emission-line region (LI(N)ER)-like regions. A harder ionizing spectrum is needed to explain DIG line ratios. Leaky HII region models can only shift line ratios slightly relative toHII region models, and thus fail to explain the composite/LI(N)ER line ratios displayed by DIG. Our result favours ionization by evolved stars as a major ionization source forDIG with LI(N)ER-like emission. DIG can significantly bias themeasurement of gas metallicity and metallicity gradients derived using strong-line methods. Metallicities derived using N2O2 are optimal because they exhibit the smallest bias and error. Using O3N2, R23, N2 = [N II]/Hα and N2S2Hα to derive metallicities introduces bias in the derived metallicity gradients as large as the gradient itself. The strong-line method of Blanc et al. (IZI hereafter) cannot be applied to DIG to get an accurate metallicity because it currently contains only HII region models that fail to describe the DIG.",

keywords = "Galaxies: ISM, Galaxies: abundances, Galaxies: active, Galaxies: evolution, Galaxies: fundamental parameters",

author = "Kai Zhang and Renbin Yan and Kevin Bundy and Matthew Bershady and {Matthew Haffner}, L. and Ren{\'e} Walterbos and Roberto Maiolino and Christy Tremonti and Daniel Thomas and Niv Drory and Amy Jones and Francesco Belfiore and S{\'a}nchez, {Sebastian F.} and Diamond-Stanic, {Aleksandar M.} and Dmitry Bizyaev and Christian Nitschelm and Brett Andrews and Jon Brinkmann and Brownstein, {Joel R.} and Edmond Cheung and Cheng Li and Law, {David R.} and Alexandre Roman-Lopes and Daniel Oravetz and Kaike Pan and Bergmann, {Thaisa Storchi} and Audrey Simmons",

note = "Funding Information: KB is supported by World Premier International Research Center Initiative (WPI Initiative), MEXT, Japan and by JSPS KAKENHI Grant Number 15K17603. MAB acknowledges support from NSF AST-1517006. RM acknowledge support by the Science and Technology Facilities Council (STFC) and the ERC Advanced Grant 695671 'QUENCH'. C.A.T. acknowledges support from National Science Foundation of the United States grant no. 1412287. DB was supported by grant RSF 14-50-00043. AD acknowledges support from The Grainger Foundation. Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the US Department of Energy Office of Science and the Participating Institutions. SDSS-IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS web site is www.sdss.org. SDSS-IV is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration including the Brazilian Participation Group, the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, the French Participation Group, Harvard-Smithsonian Center for Astrophysics, Instituto de Astrof{\'i}sica de Canarias, The Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/ University of Tokyo, Lawrence Berkeley National Laboratory, Leibniz Institut f{\"u}r Astrophysik Potsdam (AIP), Max-Planck-Institut f{\"u}r Astronomie (MPIA Heidelberg),Max-Planck-Institut f{\"u}r Astrophysik (MPA Garching),Max-Planck-Institut f{\"u}r Extraterrestrische Physik (MPE), National Astronomical Observatory of China, New Mexico State University, New York University, University of Notre Dame, Observatrio Nacional/ MCTI, The Ohio State University, Pennsylvania State University, Shanghai Astronomical Observatory, United Kingdom Participation Group, Universidad Nacional Aut{\'o}noma de M{\'e}xico, University of Arizona, University of Colorado Boulder, University of Oxford, University of Portsmouth, University of Utah, University of Virginia, University of Washington, University of Wisconsin, Vanderbilt University and Yale University. Publisher Copyright: {\textcopyright} 2016 The Authors.",

year = "2017",

month = apr,

day = "21",

doi = "10.1093/mnras/stw3308",

language = "English",

volume = "466",

pages = "3217--3243",

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Zhang, K, Yan, R, Bundy, K, Bershady, M, Matthew Haffner, L, Walterbos, R, Maiolino, R, Tremonti, C, Thomas, D, Drory, N, Jones, A, Belfiore, F, Sánchez, SF, Diamond-Stanic, AM, Bizyaev, D, Nitschelm, C, Andrews, B, Brinkmann, J, Brownstein, JR, Cheung, E, Li, C, Law, DR, Roman-Lopes, A, Oravetz, D, Pan, K, Bergmann, TS & Simmons, A 2017, 'SDSS-IV MaNGA: The impact of diffuse ionized gas on emission-line ratios, interpretation of diagnostic diagrams and gas metallicity measurements', Monthly Notices of the Royal Astronomical Society, vol. 466, no. 3, pp. 3217-3243. https://doi.org/10.1093/mnras/stw3308

TY - JOUR

T1 - SDSS-IV MaNGA

T2 - The impact of diffuse ionized gas on emission-line ratios, interpretation of diagnostic diagrams and gas metallicity measurements

AU - Zhang, Kai

AU - Yan, Renbin

AU - Bundy, Kevin

AU - Bershady, Matthew

AU - Matthew Haffner, L.

AU - Walterbos, René

AU - Maiolino, Roberto

AU - Tremonti, Christy

AU - Thomas, Daniel

AU - Drory, Niv

AU - Jones, Amy

AU - Belfiore, Francesco

AU - Sánchez, Sebastian F.

AU - Diamond-Stanic, Aleksandar M.

AU - Bizyaev, Dmitry

AU - Nitschelm, Christian

AU - Andrews, Brett

AU - Brinkmann, Jon

AU - Brownstein, Joel R.

AU - Cheung, Edmond

AU - Li, Cheng

AU - Law, David R.

AU - Roman-Lopes, Alexandre

AU - Oravetz, Daniel

AU - Pan, Kaike

AU - Bergmann, Thaisa Storchi

AU - Simmons, Audrey

N1 - Funding Information: KB is supported by World Premier International Research Center Initiative (WPI Initiative), MEXT, Japan and by JSPS KAKENHI Grant Number 15K17603. MAB acknowledges support from NSF AST-1517006. RM acknowledge support by the Science and Technology Facilities Council (STFC) and the ERC Advanced Grant 695671 'QUENCH'. C.A.T. acknowledges support from National Science Foundation of the United States grant no. 1412287. DB was supported by grant RSF 14-50-00043. AD acknowledges support from The Grainger Foundation. Funding for the Sloan Digital Sky Survey IV has been provided by the Alfred P. Sloan Foundation, the US Department of Energy Office of Science and the Participating Institutions. SDSS-IV acknowledges support and resources from the Center for High-Performance Computing at the University of Utah. The SDSS web site is www.sdss.org. SDSS-IV is managed by the Astrophysical Research Consortium for the Participating Institutions of the SDSS Collaboration including the Brazilian Participation Group, the Carnegie Institution for Science, Carnegie Mellon University, the Chilean Participation Group, the French Participation Group, Harvard-Smithsonian Center for Astrophysics, Instituto de Astrofísica de Canarias, The Johns Hopkins University, Kavli Institute for the Physics and Mathematics of the Universe (IPMU)/ University of Tokyo, Lawrence Berkeley National Laboratory, Leibniz Institut für Astrophysik Potsdam (AIP), Max-Planck-Institut für Astronomie (MPIA Heidelberg),Max-Planck-Institut für Astrophysik (MPA Garching),Max-Planck-Institut für Extraterrestrische Physik (MPE), National Astronomical Observatory of China, New Mexico State University, New York University, University of Notre Dame, Observatrio Nacional/ MCTI, The Ohio State University, Pennsylvania State University, Shanghai Astronomical Observatory, United Kingdom Participation Group, Universidad Nacional Autónoma de México, University of Arizona, University of Colorado Boulder, University of Oxford, University of Portsmouth, University of Utah, University of Virginia, University of Washington, University of Wisconsin, Vanderbilt University and Yale University. Publisher Copyright: © 2016 The Authors.

PY - 2017/4/21

Y1 - 2017/4/21

N2 - Diffuse ionized gas (DIG) is prevalent in star-forming galaxies. Using a sample of 365 nearly face-on star-forming galaxies observed byMapping Nearby Galaxies at APO, we demonstrate how DIG in star-forming galaxies impacts the measurements of emission-line ratios, hence the interpretation of diagnostic diagrams and gas-phase metallicity measurements. At fixed metallicity, DIG-dominated low ΣHα regions display enhanced [S II]/Hα, [NII]/Hα, [OII]/Hβ and [O I]/Hα. The gradients in these line ratios are determined by metallicity gradients and ΣHα. In line ratio diagnostic diagrams, contamination by DIG moves HII regions towards composite or low-ionization nuclear emission-line region (LI(N)ER)-like regions. A harder ionizing spectrum is needed to explain DIG line ratios. Leaky HII region models can only shift line ratios slightly relative toHII region models, and thus fail to explain the composite/LI(N)ER line ratios displayed by DIG. Our result favours ionization by evolved stars as a major ionization source forDIG with LI(N)ER-like emission. DIG can significantly bias themeasurement of gas metallicity and metallicity gradients derived using strong-line methods. Metallicities derived using N2O2 are optimal because they exhibit the smallest bias and error. Using O3N2, R23, N2 = [N II]/Hα and N2S2Hα to derive metallicities introduces bias in the derived metallicity gradients as large as the gradient itself. The strong-line method of Blanc et al. (IZI hereafter) cannot be applied to DIG to get an accurate metallicity because it currently contains only HII region models that fail to describe the DIG.

AB - Diffuse ionized gas (DIG) is prevalent in star-forming galaxies. Using a sample of 365 nearly face-on star-forming galaxies observed byMapping Nearby Galaxies at APO, we demonstrate how DIG in star-forming galaxies impacts the measurements of emission-line ratios, hence the interpretation of diagnostic diagrams and gas-phase metallicity measurements. At fixed metallicity, DIG-dominated low ΣHα regions display enhanced [S II]/Hα, [NII]/Hα, [OII]/Hβ and [O I]/Hα. The gradients in these line ratios are determined by metallicity gradients and ΣHα. In line ratio diagnostic diagrams, contamination by DIG moves HII regions towards composite or low-ionization nuclear emission-line region (LI(N)ER)-like regions. A harder ionizing spectrum is needed to explain DIG line ratios. Leaky HII region models can only shift line ratios slightly relative toHII region models, and thus fail to explain the composite/LI(N)ER line ratios displayed by DIG. Our result favours ionization by evolved stars as a major ionization source forDIG with LI(N)ER-like emission. DIG can significantly bias themeasurement of gas metallicity and metallicity gradients derived using strong-line methods. Metallicities derived using N2O2 are optimal because they exhibit the smallest bias and error. Using O3N2, R23, N2 = [N II]/Hα and N2S2Hα to derive metallicities introduces bias in the derived metallicity gradients as large as the gradient itself. The strong-line method of Blanc et al. (IZI hereafter) cannot be applied to DIG to get an accurate metallicity because it currently contains only HII region models that fail to describe the DIG.

KW - Galaxies: ISM

KW - Galaxies: abundances

KW - Galaxies: active

KW - Galaxies: evolution

KW - Galaxies: fundamental parameters

UR - http://www.scopus.com/inward/record.url?scp=85018285808&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=85018285808&partnerID=8YFLogxK

U2 - 10.1093/mnras/stw3308

DO - 10.1093/mnras/stw3308

M3 - Article

AN - SCOPUS:85018285808

SN - 0035-8711

VL - 466

SP - 3217

EP - 3243

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 3

ER -

SDSS-IV MaNGA: The impact of diffuse ionized gas on emission-line ratios, interpretation of diagnostic diagrams and gas metallicity measurements

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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