Metallicity Calibrations in AGNs: N₂O₂ and N₂S₂ Diagnostics

Apr 20, 2026 · 1 min read
projects

Standard strong-line diagnostics are often heavily biased by the intense radiation fields of AGNs. This ongoing project focuses on deriving new metallicity calibrations—specifically utilizing the N₂O₂ and N₂S₂ emission line ratios—that remain unaffected by structural nebular variations. By parameterizing models explicitly by intrinsic 2-10 keV X-ray luminosity, these tools lay the groundwork for analyzing high-resolution spectra from next-generation observatories.

Interactive Calibrations

N₂O₂ Simulator Demonstrating the robustness of the [N ii]/[O ii] ratio against X-ray luminosity variations compared to traditional diagnostics.

N₂S₂ Simulator Illustrating the volume-canceling properties of the [N ii]/[S ii] ratio and its independence from electron density fluctuations.

AGN Diagnostics X-Ray Astronomy Interactive Modeling
Authors
Mark Armah (He/Him)
Postdoctoral Fellow
I am an extragalactic astrophysicist specializing in the chemical evolution of Active Galactic Nuclei (AGNs) and Seyfert galaxies. My research addresses a fundamental question in galaxy evolution: how do actively accreting supermassive black holes regulate the chemical and physical properties of their host environments? By bridging the gap between intricate multi-dimensional spectroscopic datasets and advanced theoretical photoionization models, I develop custom computational pipelines to untangle AGN radiation from true gas-phase abundances. Ultimately, my work pioneers robust new metallicity calibrations and diagnostic tools that allow wider applications to decode complex AGN feedback mechanisms.