The Neon Gap: Probing Ionization with Dwarf Galaxies at z ∼ 1

Abstract We present measurements of [Ne iii ] λ 3869 emission in z ∼ 1 low-mass galaxies taken from the Keck/DEIMOS spectroscopic surveys HALO7D and DEEPwinds. identify 167 individual with significant lines, including 112 “dwarf” log ( M ⋆ stretchy="true">/ ⊙ stretchy="false">) < 9.5 , 0.3 < 1.4. also measure composite spectra derived all [O ii λλ 3727,3729 line emitters this range. This provides a unique sample between well-studied at = 0 2 3. To study evolution ionization conditions interstellar medium (ISM) over time, we analyze log([Ne 3869/[O 3727,3729) ratio (Ne3O2) as function stellar mass log([O 4959,5007/[O (O32). find that typical star-forming dwarf galaxy redshift, measured spectra, shares Ne3O2– M ⋆ relation local but has higher O32 given Ne3O2. finding implies metallicity characteristics population do not evolve substantially to 0, suggesting known those parameters largely place by 1. Individual ]-detected have situated galaxies, elevated Ne3O2 potentially explained variations nebular metallicity. compare our similarly > 7 identified JWST Early Release Observations, four dwarfs similar size, metallicity, star formation properties.