Oxygen-bearing Chemistry of PDRs under varying C/N/O Abundance Ratios

Different types of galaxies show different relative C/N/O abundance ratios. The chemistry in these systems is closely associated to Photon-dissociateion regions (PDRs), where variations in C/N/O abundances may play an important role.

A wide range of relative carbon, nitrogen, and oxygen abundances has been observed across different types of galaxies. However, most current astrochemical studies of extragalactic systems assume abundances of different elements scale uniformly with metallicity, which keeps the C/N/O ratios constant. This assumption is inconsistent with observational results.

We use 3D-PDR to model PDR chemistry with more realistic C/N/O abundance ratios. These models help us assess how variations in C/N/O ratios may affect current astrochemical conclusions of galaxy-scale systems. We also use UCLCHEM to explore additional chemical signatures in environments where dust-grain processes or shock chemistry become important.

Previous work has shown that changes in the C/O ratio can strongly affect carbon-bearing chemistry (Bisbas et al. 2024). We are now extending this investigation to oxygen-bearing species.