HII region Metallicities in Nearby Galaxies withMUSE and SITELLE

We present wide-field observations of the [OII]λλ3726, 3728 doublet across the disks of five nearby

galaxies using Spectrom`etre Imageur `a Transform´ee de Fourier pour l’Etude en Long et en Large de

raies d’Emission (SITELLE). We analyze the [OII]λλ3726, 3728 flux along with a full suite of opti-

cal emission lines in order to directly derive the electrion density, electron temperature and chemical

abundances of HII regions using auroral and nebular emission lines. We find that measurements that

make use of the nebular-to-nebular line ne,[S II] cause an overestimate in Te,[O II] by ∼ 3, 000 K and

underestimate oxygen abundances by ∼ 0.1 dex. The [OII] auroral-to-nebular diagnostic in combina-

tion with Te,[N II] is used to derive ne,[O II]7325+/3727+, which is found to minimize the effects of density

inhomogeneities. Our findings also suggest that temperature inhomogeneities may be present in the

intermediate ionization volumne, which may be biasing Te,[S III] derived abundances to be underesti-

mated by a factor of ∼ 5. These results ultimately conclude that the abundance discrepancy factor

is more prevalent in chemically enriched HII regions and that when our directly calculated oxygen

abundances are compared to a number of strong line calibrations, the Dopita et al. (2016) relation

yields the best oxygen abundance estimations.