The SAMI Galaxy Survey: Reconciling strong emission line metallicity diagnostics using metallicity gradients

Henry Poetrodjojo; Brent Groves; Lisa J. Kewley; Sarah M. Sweet; Sebastian F. Sanchez; Anne M. Medling; Ángel R. López-Sánchez; Sarah Brough; Luca Cortese; Jesse Van De Sande; Sam Vaughan; Samuel N. Richards; Julia J. Bryant; Scott M. Croom; Joss Bland-Hawthorn; Michael Goodwin; Jon S. Lawrence; Matt S. Owers; Nicholas Scott

doi:10.1093/mnras/stab205

The SAMI Galaxy Survey: Reconciling strong emission line metallicity diagnostics using metallicity gradients

Henry Poetrodjojo^*, Brent Groves, Lisa J. Kewley, Sarah M. Sweet, Sebastian F. Sanchez, Anne M. Medling, Ángel R. López-Sánchez, Sarah Brough, Luca Cortese, Jesse Van De Sande, Sam Vaughan, Samuel N. Richards, Julia J. Bryant, Scott M. Croom, Joss Bland-Hawthorn, Michael Goodwin, Jon S. Lawrence, Matt S. Owers, Nicholas Scott

^*Corresponding author for this work

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

19 Citations (Scopus)

Abstract

We measure the gas-phase metallicity gradients of 248 galaxies selected from Data Release 2 of the SAMI Galaxy Survey. We demonstrate that there are large systematic discrepancies between the metallicity gradients derived using common strong emission line metallicity diagnostics. We determine which pairs of diagnostics have Spearman's rank coefficients greater than 0.6 and provide linear conversions to allow the accurate comparison of metallicity gradients derived using different strong emission line diagnostics. For galaxies within the mass range 8.5 < log (M/M·) < 11.0, we find discrepancies of up to 0.11 dex/Re between seven popular diagnostics in the metallicity gradient-mass relation. We find a suggestion of a break in the metallicity gradient-mass relation, where the slope shifts from negative to positive, occurs between 9.5 < log (M/Mmiddot;) < 10.5 for the seven chosen diagnostics. Applying our conversions to the metallicity gradient-mass relation, we reduce the maximum dispersion from 0.11 dex/Re to 0.02 dex/Re. These conversions provide the most accurate method of converting metallicity gradients when key emission lines are unavailable. We find that diagnostics that share common sets of emission line ratios agree best, and that diagnostics calibrated through the electron temperature provide more consistent results compared to those calibrated through photoionization models.

Original language	English
Pages (from-to)	3357-3373
Number of pages	17
Journal	Monthly Notices of the Royal Astronomical Society
Volume	502
Issue number	3
DOIs	https://doi.org/10.1093/mnras/stab205
Publication status	Published - 1 Apr 2021

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Poetrodjojo, H., Groves, B., Kewley, L. J., Sweet, S. M., Sanchez, S. F., Medling, A. M., López-Sánchez, Á. R., Brough, S., Cortese, L., Van De Sande, J., Vaughan, S., Richards, S. N., Bryant, J. J., Croom, S. M., Bland-Hawthorn, J., Goodwin, M., Lawrence, J. S., Owers, M. S., & Scott, N. (2021). The SAMI Galaxy Survey: Reconciling strong emission line metallicity diagnostics using metallicity gradients. Monthly Notices of the Royal Astronomical Society, 502(3), 3357-3373. https://doi.org/10.1093/mnras/stab205

@article{35e987c5dc1a43ee96ef55b6c0114024,

title = "The SAMI Galaxy Survey: Reconciling strong emission line metallicity diagnostics using metallicity gradients",

abstract = "We measure the gas-phase metallicity gradients of 248 galaxies selected from Data Release 2 of the SAMI Galaxy Survey. We demonstrate that there are large systematic discrepancies between the metallicity gradients derived using common strong emission line metallicity diagnostics. We determine which pairs of diagnostics have Spearman's rank coefficients greater than 0.6 and provide linear conversions to allow the accurate comparison of metallicity gradients derived using different strong emission line diagnostics. For galaxies within the mass range 8.5 < log (M/M·) < 11.0, we find discrepancies of up to 0.11 dex/Re between seven popular diagnostics in the metallicity gradient-mass relation. We find a suggestion of a break in the metallicity gradient-mass relation, where the slope shifts from negative to positive, occurs between 9.5 < log (M/Mmiddot;) < 10.5 for the seven chosen diagnostics. Applying our conversions to the metallicity gradient-mass relation, we reduce the maximum dispersion from 0.11 dex/Re to 0.02 dex/Re. These conversions provide the most accurate method of converting metallicity gradients when key emission lines are unavailable. We find that diagnostics that share common sets of emission line ratios agree best, and that diagnostics calibrated through the electron temperature provide more consistent results compared to those calibrated through photoionization models.",

keywords = "galaxies: ISM, galaxies: abundances, galaxies: fundamental parameters",

author = "Henry Poetrodjojo and Brent Groves and Kewley, {Lisa J.} and Sweet, {Sarah M.} and Sanchez, {Sebastian F.} and Medling, {Anne M.} and L{\'o}pez-S{\'a}nchez, {{\'A}ngel R.} and Sarah Brough and Luca Cortese and {Van De Sande}, Jesse and Sam Vaughan and Richards, {Samuel N.} and Bryant, {Julia J.} and Croom, {Scott M.} and Joss Bland-Hawthorn and Michael Goodwin and Lawrence, {Jon S.} and Owers, {Matt S.} and Nicholas Scott",

note = "Publisher Copyright: {\textcopyright} 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.",

year = "2021",

month = apr,

day = "1",

doi = "10.1093/mnras/stab205",

language = "English",

volume = "502",

pages = "3357--3373",

journal = "Monthly Notices of the Royal Astronomical Society",

issn = "0035-8711",

publisher = "Oxford University Press ",

number = "3",

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Poetrodjojo, H, Groves, B, Kewley, LJ, Sweet, SM, Sanchez, SF, Medling, AM, López-Sánchez, ÁR, Brough, S, Cortese, L, Van De Sande, J, Vaughan, S, Richards, SN, Bryant, JJ, Croom, SM, Bland-Hawthorn, J, Goodwin, M, Lawrence, JS, Owers, MS & Scott, N 2021, 'The SAMI Galaxy Survey: Reconciling strong emission line metallicity diagnostics using metallicity gradients', Monthly Notices of the Royal Astronomical Society, vol. 502, no. 3, pp. 3357-3373. https://doi.org/10.1093/mnras/stab205

TY - JOUR

T1 - The SAMI Galaxy Survey

T2 - Reconciling strong emission line metallicity diagnostics using metallicity gradients

AU - Poetrodjojo, Henry

AU - Groves, Brent

AU - Kewley, Lisa J.

AU - Sweet, Sarah M.

AU - Sanchez, Sebastian F.

AU - Medling, Anne M.

AU - López-Sánchez, Ángel R.

AU - Brough, Sarah

AU - Cortese, Luca

AU - Van De Sande, Jesse

AU - Vaughan, Sam

AU - Richards, Samuel N.

AU - Bryant, Julia J.

AU - Croom, Scott M.

AU - Bland-Hawthorn, Joss

AU - Goodwin, Michael

AU - Lawrence, Jon S.

AU - Owers, Matt S.

AU - Scott, Nicholas

PY - 2021/4/1

Y1 - 2021/4/1

N2 - We measure the gas-phase metallicity gradients of 248 galaxies selected from Data Release 2 of the SAMI Galaxy Survey. We demonstrate that there are large systematic discrepancies between the metallicity gradients derived using common strong emission line metallicity diagnostics. We determine which pairs of diagnostics have Spearman's rank coefficients greater than 0.6 and provide linear conversions to allow the accurate comparison of metallicity gradients derived using different strong emission line diagnostics. For galaxies within the mass range 8.5 < log (M/M·) < 11.0, we find discrepancies of up to 0.11 dex/Re between seven popular diagnostics in the metallicity gradient-mass relation. We find a suggestion of a break in the metallicity gradient-mass relation, where the slope shifts from negative to positive, occurs between 9.5 < log (M/Mmiddot;) < 10.5 for the seven chosen diagnostics. Applying our conversions to the metallicity gradient-mass relation, we reduce the maximum dispersion from 0.11 dex/Re to 0.02 dex/Re. These conversions provide the most accurate method of converting metallicity gradients when key emission lines are unavailable. We find that diagnostics that share common sets of emission line ratios agree best, and that diagnostics calibrated through the electron temperature provide more consistent results compared to those calibrated through photoionization models.

AB - We measure the gas-phase metallicity gradients of 248 galaxies selected from Data Release 2 of the SAMI Galaxy Survey. We demonstrate that there are large systematic discrepancies between the metallicity gradients derived using common strong emission line metallicity diagnostics. We determine which pairs of diagnostics have Spearman's rank coefficients greater than 0.6 and provide linear conversions to allow the accurate comparison of metallicity gradients derived using different strong emission line diagnostics. For galaxies within the mass range 8.5 < log (M/M·) < 11.0, we find discrepancies of up to 0.11 dex/Re between seven popular diagnostics in the metallicity gradient-mass relation. We find a suggestion of a break in the metallicity gradient-mass relation, where the slope shifts from negative to positive, occurs between 9.5 < log (M/Mmiddot;) < 10.5 for the seven chosen diagnostics. Applying our conversions to the metallicity gradient-mass relation, we reduce the maximum dispersion from 0.11 dex/Re to 0.02 dex/Re. These conversions provide the most accurate method of converting metallicity gradients when key emission lines are unavailable. We find that diagnostics that share common sets of emission line ratios agree best, and that diagnostics calibrated through the electron temperature provide more consistent results compared to those calibrated through photoionization models.

KW - galaxies: ISM

KW - galaxies: abundances

KW - galaxies: fundamental parameters

UR - http://www.scopus.com/inward/record.url?scp=85105040693&partnerID=8YFLogxK

U2 - 10.1093/mnras/stab205

DO - 10.1093/mnras/stab205

M3 - Article

SN - 0035-8711

VL - 502

SP - 3357

EP - 3373

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 3

ER -

The SAMI Galaxy Survey: Reconciling strong emission line metallicity diagnostics using metallicity gradients

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