| Name: | SUSMITA BARMAN |
| Affiliation: | University Of Hyderabad |
| Conference ID : | ASI2023_189 |
| Title : | A Study of Photoionized Gas in Two HII Regions of the N44 Complex in the LMC Using MUSE Observations |
| Authors : | Susmita Barman, Naslim Neelamkodan, Suzanne C. Madden, Marta Sewilo, Francisca Kemper,
Kazuki Tokuda, Soma Sanyal, and Toshikazu Onishi |
| Mode of Presentation: | Oral |
| Abstract Category : | Stars, ISM and Galaxy |
| Abstract : | We present the ionisation structure and physical conditions of two luminous H II
regions in the N44 star-forming complex of the Large Magellanic Cloud using the CLOUDY
spectral synthesis code and the observations with the Multi-Unit Spectroscopic Explorer
(MUSE) of the Very Large Telescope. The spatial distributions of various spectral lines in
N44D1 show a stratified ionisation geometry, whereas N44C does not. The [SII]/Hα and
[NII]/Hβ line ratio maps show an evident shell structure in both N44D1 and N44C. We use
our spatially resolved MUSE spectra results to explore the photoionisation models with
CLOUDY that can describe the observed geometry and emission line ratios. We find that the
constant-density model gives better geometry and line ratios than the constant-pressure
model in N44D1. A spherically symmetric ionisation-bounded model with a partial covering
factor, which is appropriate for a blister H II region, produces the observed geometry and
most of the diagnostic line ratios in N44D1. An optically thin and open geometry model has
been applied to produce the observed geometry and line ratios in N44C. Our modelling
results exhibit that the radiation from the O5V star determines the ionisation structure and
physical conditions of N44D1. In addition, a significant amount of X-rays, possibly from
supernovae or stellar wind, play a crucial role in the N44D1. In N44C, the main contribution
is from three ionising hot stars. Our study indicates that the stellar radiation and thermal gas
pressure regulate the ionisation structure and the physical conditions in N44D1 and N44C. |
