A study of photoionized gas in two HII regions of the N44 complex in the
  LMC using MUSE observations
  We use the optical integral field observations with Multi-Unit Spectroscopic
Explorer (MUSE) on the Very Large Telescope, together with CLOUDY
photoionization models to study ionization structure and physical conditions of
two luminous HII regions in N44 star-forming complex of the Large Magellanic
Cloud. The spectral maps of various emission lines reveal a stratified
ionization geometry in N44 D1. The spatial distribution of [O I] 6300A emission
in N44 D1 indicates a partially covered ionization front at the outer boundary
of the H II region. These observations reveal that N44 D1 is a Blister HII
region. The [O I] 6300A emission in N44 C does not provide a well-defined
ionization front at the boundary, while patches of [S II] 6717 A and [O I]
6300A emission bars are found in the interior. The results of spatially
resolved MUSE spectra are tested with the photoionization models for the first
time in these HII regions. A spherically symmetric ionization-bounded model
with a partial covering factor, which is appropriate for a Blister HII region
can well reproduce the observed geometry and most of the diagnostic line ratios
in N44 D1. Similarly, in N44 C we apply a low density and optically thin model
based on the observational signatures. Our modeling results show that the
ionization structure and physical conditions of N44 D1 are mainly determined by
the radiation from an O5 V star. However, local X-rays, possibly from
supernovae or stellar wind, play a key role. In N44 C, the main contribution is
from three ionizing stars.
