The MOSDEF survey: Neon as a probe of ISM physical conditions at high redshift

Authors

• Moon-Seong Jeong, University of California, Los Angeles
• Alice E. Shapley, University of California, Los Angeles
• Ryan L. Sanders, University of California, Los Angeles
• Jordan N. Runco, University of California, Los Angeles
• Michael W. Topping, University of California, Los Angeles
• Naveen A. Reddy, University of California, Riverside
• Mariska Kriek, University of California, Berkeley
• Alison L. Coil, University of California, San Diego
• Bahram Mobasher, University of California, Riverside
• Brian Siana, University of California, Riverside
• Irene Shivaei, The University of Arizona
• William R. Freeman, University of California, Riverside
• Mojegan Azadi, Harvard-Smithsonian Center for Astrophysics
• Sedona H. Price, Max Planck Institute for Extraterrestrial Physics
• Gene C.K. Leung, Center for Astrophysics & Space Sciences
• Tara Fetherolf, University of California, Riverside
• Laura de Groot, The College of Wooster
• Tom Zick, University of California, Berkeley
• Francesca M. Fornasini, Harvard-Smithsonian Center for Astrophysics
• Guillermo Barro, University of the PacificFollow

Document Type

Article

Publication Title

Astrophysical Journal Letters

Department

Physics

ISSN

20418213

Volume

902

Issue

1

DOI

10.3847/2041-8213/abba7a

First Page

1

Last Page

7

Publication Date

10-8-2020

Abstract

We present results on the properties of neon emission in z ∼ 2 star-forming galaxies drawn from the MOSFIRE Deep Evolution Field (MOSDEF) survey. Doubly ionized neon ([Ne III]λ3869) is detected at 3σ in 61 galaxies, representing ∼25% of the MOSDEF sample with Hα, Hβ, and [O III]λ5007 detections at similar redshifts. We consider the neon emission-line properties of both individual galaxies with [Ne III]λ3869 detections and composite z ∼ 2 spectra binned by stellar mass. With no requirement of [Ne III]λ3869 detection, the latter provide a more representative picture of neon emission-line properties in the MOSDEF sample. The [Ne III]λ3869/[O II]λ3727 ratio (Ne3O2) is anticorrelated with stellar mass in z ∼ 2 galaxies, as expected based on the mass–metallicity relation. It is also positively correlated with the [O III]λ5007/[O II]λ3727 ratio (O32), but z ∼ 2 line ratios are offset toward higher Ne3O2 at fixed O32, compared with both local star-forming galaxies and individual H II regions. Despite the offset toward higher Ne3O2 at fixed O32 at z ∼ 2, biases in inferred Ne3O2-based metallicity are small. Accordingly, Ne3O2 may serve as an important metallicity indicator deep into the reionization epoch. Analyzing additional rest-optical line ratios including [Ne III]λ3869/[O III]λ5007 (Ne3O3) and [O III]λ5007/Hβ (O3Hβ), we conclude that the nebular emission-line ratios of z ∼ 2 star-forming galaxies suggest a harder ionizing spectrum (lower stellar metallicity, i.e., Fe/H) at fixed gas-phase oxygen abundance, compared to systems at z ∼ 0. These new results based on neon lend support to the physical picture painted by oxygen, nitrogen, hydrogen, and sulfur emission of an ionized interstellar medium in high-redshift star-forming galaxies irradiated by chemically young, α-enhanced massive stars.

Creative Commons License

This work is licensed under a Creative Commons Attribution 4.0 International License.

Recommended Citation

Jeong, Moon-Seong; Shapley, Alice E.; Sanders, Ryan L.; Runco, Jordan N.; Topping, Michael W.; Reddy, Naveen A.; Kriek, Mariska; Coil, Alison L.; Mobasher, Bahram; Siana, Brian; Shivaei, Irene; Freeman, William R.; Azadi, Mojegan; Price, Sedona H.; Leung, Gene C.K.; Fetherolf, Tara; de Groot, Laura; Zick, Tom; Fornasini, Francesca M.; and Barro, Guillermo, "The MOSDEF survey: Neon as a probe of ISM physical conditions at high redshift" (2020). Pacific Faculty Work. 297.
https://scholarlycommons.pacific.edu/all-faculty/297