We present measurements of [NeIII]{\lambda}3869 emission in z~1 low-mass
galaxies taken from the Keck/DEIMOS spectroscopic surveys HALO7D and DEEPWinds.
We identify 167 individual galaxies with significant [NeIII] emission lines,
including 112 "dwarf" galaxies with log(M_{\star}/M_{\odot}) < 9.5, with 0.3 <
z < 1.4. We also measure [NeIII] emission from composite spectra derived from
all [OII]{\lambda}{\lambda}3727,3729 line emitters in this range. This provides
a unique sample of [NeIII]-emitters in the gap between well-studied emitters at
z = 0 and 2 < z < 3. To study evolution in ionization conditions in the ISM
over this time, we analyze the
log([NeIII]{\lambda}3869/[OII]{\lambda}{\lambda}3727,3729) ratio (Ne3O2) as a
function of the stellar mass and of the
log([OIII]{\lambda}{\lambda}4959,5007/[OII]{\lambda}{\lambda}3727,3729) ratio
(O32). We find that the typical star-forming dwarf galaxy at this redshift, as
measured from the composite spectra, shares the Ne3O2-M_{\star} relation with
local galaxies, but have higher O32 at given Ne3O2. This finding implies that
the ionization and metallicity characteristics of the z~1 dwarf population do
not evolve substantially from z~1 to z=0, suggesting that the known evolution
in those parameter from z~2 has largely taken place by z~1. Individual
[NeIII]-detected galaxies have emission characteristics situated between local
and z~2 galaxies, with elevated Ne3O2 and O32 emission potentially explained by
variations in stellar and nebular metallicity. We also compare our dwarf sample
to similarly low-mass z > 7 galaxies identified in JWST Early Release
Observations, finding four HALO7D dwarfs with similar size, metallicity, and
star formation properties.Comment: Accepted to ApJL, 16.01.202
