Environmental dependence of protocluster-galaxy metallicity

Determine whether protocluster galaxies exhibit higher gas-phase metal content than photometrically selected galaxies from the general population during the epoch of reionization, when enhanced gas accretion and feedback may modify environmental effects.

Background

The paper motivates gas-phase metallicity as a tracer of galaxy evolution and uses the mass–metallicity relation to investigate how accretion, star formation, and feedback regulate chemical enrichment. Previous observations at high redshift have reported conflicting environmental trends, including no significant dependence, metal enrichment, and metallicity dilution in overdense regions.

The authors emphasize that the uncertainty is especially important during the epoch of reionization, when protocluster environments may contain enhanced gas accretion and feedback. Their JWST/NIRSpec measurements of Lyman-alpha emitters in the LAGER-z7OD1 protocluster provide evidence relevant to this issue, but the small sample and selection of actively star-forming emitters do not fully resolve whether protocluster galaxies are systematically more metal-rich than comparable galaxies in the general population.

References

It remains unclear whether protocluster galaxies exhibit higher metal content than photometrically selected galaxies from the general population, particularly during the epoch of reionization where environmental effects may be modulated by enhanced gas accretion or feedback.

— Galaxy Protoclusters as Drivers of Cosmic Reionization: II. Te-Based Metallicities of Lyman-α Emitters  (2610.01811 - Moya-Sierralta et al., 1 Oct 2026) in Introduction, paragraph discussing the environmental impact on galaxy chemical evolution