Electron Densities of Typical Low-Mass Galaxies at z~2-7 from Stacked JWST/NIRSpec Spectra

Shihong Liu; Yu Rong

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arXiv · 2606.31549

Electron Densities of Typical Low-Mass Galaxies at z~2-7 from Stacked JWST/NIRSpec Spectra

Shihong Liu·Yu Rong

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Abstract

Direct electron-density measurements at high redshift are usually limited to galaxies with individually strong density-sensitive doublets, and therefore may not trace the average interstellar medium of ordinary low-mass galaxies. We stack public JWST/NIRSpec medium-resolution spectra from the DAWN JWST Archive to measure [SII]-based electron densities $n_e$ for low-mass galaxies at $2 5$ have a higher normalization, $n_{e,0}=211^{+36}_{-31}\ {\rm cm^{-3}}$, showing that individual-doublet samples select a denser subset. Stacking archival JWST spectra therefore provides a direct route to measuring the average gas density of low-mass galaxies below the individual-doublet detection threshold.

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Shihong Liu, Yu Rong. 2026-06-30. Electron Densities of Typical Low-Mass Galaxies at z~2-7 from Stacked JWST/NIRSpec Spectra. https://arxiv.org/abs/2606.31549

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