Joint Optical and Infrared Observations of Nitrogen and Oxygen Reveal the Dust-obscured Gas in Haro 3

Authors

• Yuguang Chen, Chinese University of Hong KongFollow
• Tucker Jones, University of California Davis
• Ryan L. Sanders, University of KentuckyFollow
• Dario Fadda, Space Telescope Science Institute
• Jessica Sutter, Whitman College
• Robert Minchin, California Institute of Technology
• Nikolaus Z. Prusinski, Carnegie Institution of Washington
• Sunny Rhoades, University of California Davis
• G. C. Keerthi Vasan, University of California Davis
• Charles C. Steidel, Carnegie Institution of Washington
• Erin Huntzinger, University of California Davis
• Paige Kelly, University of California Davis
• Danielle A. Berg, Universidad de Concepción
• Fabio Bresolin, Millennium Nucleus for Galaxies (MINGAL)
• Rodrigo Herrera-Camus, University College London
• Ryan J. Rickards Vaught, Space Telescope Science Institute
• Guido Roberts-Borsani, University of California Berkeley
• Peter Senchyna, University of Arizona
• Justin S. Spilker, W. M. Keck Observatory
• Daniel P. Stark
• Benjamin Weiner
• D. Christopher Martin, Carnegie Institution of Washington
• Mateusz Matuszewski, Carnegie Institution of Washington
• Rosalie C. McGurk
• James D. Neill, Carnegie Institution of Washington

Abstract

Accurate chemical compositions of star-forming regions provide a critical diagnostic tool for characterizing the star formation history and gas flows that regulate galaxy formation. However, the abundance discrepancy factor (ADF) between measurements derived from the “direct” optical electron temperature (T_e ) method and those from recombination lines (RLs) introduces a ∼0.2 dex systematic uncertainty in the oxygen abundance. The degree of uncertainty for other elements is unknown. We conduct a comprehensive analysis of O⁺⁺ and N⁺ ion abundances using optical and far-infrared (far-IR) spectra of a star-forming region within the nearby dwarf galaxy Haro 3, which exhibits a typical ADF. Assuming homogeneous conditions, the far-IR emission indicates an oxygen abundance higher than that derived using the T_e method and consistent with the RL value, as expected from temperature fluctuations, whereas the far-IR nitrogen abundance is too large to be explained by temperature fluctuations. A two-phase analytical model reveals that differential dust obscuration associated with temperature inhomogeneity is likely required to explain all the emission-line ratios, and that the total oxygen metallicity of two phases is consistent with the RL metallicity. Our findings underscore the critical importance of resolving the cause of abundance discrepancies and understanding the biases between different metallicity methods. This work presents a promising methodology, and we identify further approaches to address the dominant sources of uncertainty.

Document Type

Article

Publication Date

3-20-2026

Notes/Citation Information

Publisher Copyright: © 2026. The Author(s). Published by the American Astronomical Society.

Digital Object Identifier (DOI)

10.3847/1538-4357/ae473e

Archival?

Archival

Repository Citation

Chen, Yuguang; Jones, Tucker; Sanders, Ryan L.; Fadda, Dario; Sutter, Jessica; Minchin, Robert; Prusinski, Nikolaus Z.; Rhoades, Sunny; Keerthi Vasan, G. C.; Steidel, Charles C.; Huntzinger, Erin; Kelly, Paige; Berg, Danielle A.; Bresolin, Fabio; Herrera-Camus, Rodrigo; Rickards Vaught, Ryan J.; Roberts-Borsani, Guido; Senchyna, Peter; Spilker, Justin S.; Stark, Daniel P.; Weiner, Benjamin; Martin, D. Christopher; Matuszewski, Mateusz; McGurk, Rosalie C.; and Neill, James D., "Joint Optical and Infrared Observations of Nitrogen and Oxygen Reveal the Dust-obscured Gas in Haro 3" (2026). Physics and Astronomy Faculty Publications. 785.
https://uknowledge.uky.edu/physastron_facpub/785