Determine the mechanisms governing PAH destruction, survival, and migration

Determine the physical mechanisms governing polycyclic aromatic hydrocarbon destruction, survival, and migration in and around extragalactic H II regions, particularly across different evolutionary stages and interstellar-medium conditions.

Background

The paper finds that regions with lower filling factors tend to exhibit higher PAH-to-dust ratios, consistent with less efficient PAH processing in more porous ionized-gas structures. The authors interpret this behavior within a tentative evolutionary scenario in which intense radiation fields initially destroy PAHs, while later gas dispersal weakens PAH destruction.

That interpretation is not expected to be uniform because PAH behavior may also depend on local density structure, radiation fields, shocks, grain processing, and transport. The authors therefore identify the underlying mechanisms of PAH destruction, survival, and migration as unresolved.