| Tracing Gas Ionization in Galaxies |
| Xihan Ji, University of Kentucky |
| Event Type: Informal Astro Talk |
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| Time: 11:00 AM - 11:30 AM |
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| Location: 726 Broadway, 940, CCPP Seminar |
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| Abstract: Young massive stars create HII regions and drive them to expand over time through the energetic feedback. Due to the small physical sizes and low expanding velocities of most HII regions, it is difficult to study their dynamical evolution directly. Interestingly, early dynamical models predict that stellar feedback results in a correlation between the metallicity and ionization parameter in HII regions. This correlation provides a unique way to investigate the impact of stellar feedback on small scales using nebular diagnostics. However, previous works derived discrepant correlations from observations. In this talk, I will introduce our solution with a refined calibration method using photoionization models. We applied our method to the HII regions in SDSS-IV MaNGA, and found that the stellar-wind feedback model alone is insufficient to explain the derived correlation. To further understand this issue, I plan to investigate the detailed ionization structures of HII regions using the upcoming surveys on the local ISM. |