# JWST's TEMPLATES for Star Formation: The First Resolved Gas-Phase Metallicity Maps of Dust-Obscured Star-Forming Galaxies at $z$ $\sim$ 4

**Authors:** Jack E. Birkin, Taylor A. Hutchison, Brian Welch, Justin S. Spilker, Manuel Aravena, Matthew B. Bayliss, Jared Cathey, Scott C. Chapman, Anthony H. Gonzalez, Gayathri Gururajan, Christopher C. Hayward, Gourav Khullar, Keunho J. Kim, Guillaume Mahler, Matthew A. Malkan, Desika Narayanan, Grace M. Olivier, Kedar A. Phadke, Cassie Reuter, Jane R. Rigby  
**arXiv:** [2307.10412](https://arxiv.org/abs/2307.10412)  
**Date:** 2023-07-19  
**Summary page:** https://www.summarizepaper.com/en/paper/2307.10412v1/

## Key points

- Authors present first spatially resolved maps of gas-phase metallicity for dust-obscured star-forming galaxies (DSFGs) at redshift 4
- Maps obtained from JWST TEMPLATES Early Release Science program using NIRSpec integral field unit spectroscopy
- DSFGs found to be highly metal-rich based on empirically derived literature optical line calibrations
- Regions of supersolar metallicity observed in both galaxies, with SPT2147-50 showing particularly high levels of enrichment
- Presence of shocks or active galactic nuclei (AGN) cannot be ruled out, but authors suggest high star formation rates as the main cause of enrichment
- ALMA rest-frame 380μm continuum and [CI](3P2–3P1) line maps used to compare variations in metallicity and gas-to-dust ratio
- Anticorrelation found between metallicity and gas-to-dust ratio on small spatial scales, consistent with previous studies at lower redshifts
- Stellar feedback likely responsible for enriching interstellar medium during this epoch
- Findings demonstrate potential of JWST to probe galaxy evolution on small scales and provide constraints for theoretical models

## Summary

In this study, the authors present the first spatially resolved maps of gas-phase metallicity for dust-obscured star-forming galaxies (DSFGs) at a redshift of approximately 4. These maps were obtained from the JWST TEMPLATES Early Release Science program using NIRSpec integral field unit spectroscopy of the Hα and [NII] emission lines. By utilizing empirically derived literature optical line calibrations, the authors determine that these DSFGs are highly metal-rich. They observe regions of supersolar metallicity in both galaxies, with SPT2147-50 displaying particularly high levels of metal enrichment. While the presence of shocks or active galactic nuclei (AGN) cannot be ruled out in these regions, the authors suggest that these two systems have already undergone significant enrichment due to their extremely high star formation rates. To further investigate the properties of these galaxies, the authors compare variations in metallicity and gas-to-dust ratio using ALMA rest-frame 380μm continuum and [CI](3P2–3P1) line maps. They find an anticorrelation between metallicity and gas-to-dust ratio on highly resolved spatial scales, consistent with previous studies of galaxies at a redshift around 0. This suggests that processes such as stellar feedback are responsible for enriching interstellar medium with heavy elements during this epoch. Overall, these findings demonstrate the enormous potential of JWST to probe galaxy evolution on scales as small as kiloparsecs in extremely dust obscured systems at a redshift around 4 and beyond. The results contribute to our understanding of galaxy formation and provide important constraints for theoretical models. The paper is currently submitted to ApJ and consists of 12 pages along with 5 figures. In this study, the authors present spatially resolved maps of gas phase metallicity for dust obscured star forming galaxies (DSFGs) at a redshift around 4 obtained from JWST TEMPLATES Early Release Science program using NIRSpec integral field unit spectroscopy. Utilizing empirically derived literature optical line calibrations they determine that DSFGs are highly metal rich with regions displaying supersolar metallicity likely due to their high star formation rates rather than shocks or active galactic nuclei (AGN). To further investigate properties they compare variations in metallicity and gas to dust ratio using ALMA rest frame 380μm continuum and [CI](3P2–3P1) line maps finding an anticorrelation consistent with previous studies at lower redshifts suggesting stellar feedback is responsible for enriching interstellar medium during this epoch. These findings demonstrate potential for JWST to probe galaxy evolution on small scales providing valuable insights into early stages of galaxy formation while shedding light on processes responsible for enriching galaxies with heavy elements during this epoch offering important constraints for theoretical models.