Effects of density and temperature variations on the metallicity of mrk 71

Access through your institution Buy or subscribe arising from Y. Chen et al. _Nature Astronomy_ https://doi.org/10.1038/s41550-023-01953-7 (2023) Historically, two indicators of heavy

element abundances in ionized nebulae—optical collisionally excited lines (CELs) with an exponential temperature (_T_e) dependence and recombination lines (RLs) with less _T_e

sensitivity—have produced inconsistent results. By using the less _T_e-dependent infrared (IR) [O iii] CELs, Chen et al.1 argue that the temperature inhomogeneities scenario proposed by

Peimbert2 cannot explain the abundance discrepancy in the star-forming galaxy Mrk 71. We show that this conclusion depends on several assumptions, mainly the absence of biases in electron

density (_n_e) determinations, a parameter on which IR CELs depend more than optical CELs. Since multiple _n_e indicators in previous and the discussed work on Mrk 71 show important

differences, we conclude that the existence of temperature inhomogeneities cannot be ruled out. This is a preview of subscription content, access via your institution ACCESS OPTIONS Access

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Contact customer support DATA AVAILABILITY All the data discussed here were presented by ref. 1. CODE AVAILABILITY Our results use the PyNeb code, publicly available on GitHub:

https://github.com/Morisset/PyNeb_devel. REFERENCES * Chen, Y. et al. Accurate oxygen abundance of interstellar gas in Mrk 71 from optical and infrared spectra. _Nat. Astron._ 7, 771–778

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(2023). Article  ADS  Google Scholar  Download references ACKNOWLEDGEMENTS J.E.M.-D. and K.K. gratefully acknowledge funding from the German Research Foundation in the form of an Emmy

Noether Research Group (grant no. KR4598/2-1, PI Kreckel). K.K. additionally gratefully acknowledges funding from the European Research Council’s starting grant (grant no. ERC StG-101077573,

ISM-METALS). C.E. and J.G.-R. acknowledge support from the Spanish Research Agency of the Ministry of Science, Innovation and Universities (MCIU) under grant Espectroscopía de campo

integral de regiones H ii locales. Modelos para el estudio de regiones H ii extragalácticas (grant ref. 10.13039/501100011033) and support (grant no. P/308614), which is financed by the MCIU

and charged to the General State Budgets and by the General Budgets of the Autonomous Community of the Canary Islands by the MCIU. J.G.-R. acknowledges support from an advanced fellowship

under the Severo Ochoa excellence programme (ref. CEX2019-000920-S) and financial support from the Canarian Agency for Research, Innovation and Information Society of the Canary Islands

Government and from the European Regional Development Fund (grant ref. ProID2021010074). AUTHOR INFORMATION AUTHORS AND AFFILIATIONS * Astronomisches Rechen-Institut, Zentrum für Astronomie

der Universität Heidelberg, Heidelberg, Germany J. Eduardo Méndez-Delgado & Kathryn Kreckel * Instituto de Astrofísica de Canarias (IAC), Santa Cruz de Tenerife, Spain César Esteban 

& Jorge García-Rojas * Departamento de Astrofísica, Universidad de La Laguna, Santa Cruz de Tenerife, Spain César Esteban & Jorge García-Rojas * Instituto de Astronomía, Universidad

Nacional Autónoma de México, Mexico City, Mexico Manuel Peimbert Authors * J. Eduardo Méndez-Delgado View author publications You can also search for this author inPubMed Google Scholar *

César Esteban View author publications You can also search for this author inPubMed Google Scholar * Jorge García-Rojas View author publications You can also search for this author inPubMed 

Google Scholar * Kathryn Kreckel View author publications You can also search for this author inPubMed Google Scholar * Manuel Peimbert View author publications You can also search for this

author inPubMed Google Scholar CONTRIBUTIONS J.E.M.-D. led the analysis and writing of the manuscript. C.E., J.G.-R., K.K. and M.P. provided critical feedback and modified the text.

CORRESPONDING AUTHOR Correspondence to J. Eduardo Méndez-Delgado. ETHICS DECLARATIONS COMPETING INTERESTS The authors declare no competing interests. PEER REVIEW PEER REVIEW INFORMATION

_Nature Astronomy_ thanks the anonymous reviewers for their contribution to the peer review of this work. ADDITIONAL INFORMATION PUBLISHER’S NOTE Springer Nature remains neutral with regard

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C., García-Rojas, J. _et al._ Effects of density and temperature variations on the metallicity of Mrk 71. _Nat Astron_ 8, 275–277 (2024). https://doi.org/10.1038/s41550-024-02198-8 Download

citation * Received: 19 June 2023 * Accepted: 08 January 2024 * Published: 05 February 2024 * Issue Date: March 2024 * DOI: https://doi.org/10.1038/s41550-024-02198-8 SHARE THIS ARTICLE

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