Spatially Resolved Gas-Phase Metallicity

Oct 1, 2024 · 1 min read
projects

Moving beyond integrated single-fiber spectra, this project utilizes optical Integral Field Unit (IFU) observations from the Gemini Multi-Object Spectrograph (GMOS) and the Multi Unit Spectroscopic Explorer (MUSE) to map the 2D chemical composition of 15 nearby Seyfert galaxies (comprising 9 GMOS and 6 MUSE datasets). By probing the inner few hundred parsecs, this spatially resolved approach reveals exactly how gas-phase metallicity fluctuates within the active nucleus. Specifically, we demonstrate that these local Seyferts exhibit positive (inverted) metallicity radial profiles over extended periods due to seamless gas accretion histories. Furthermore, our spatially resolved data establishes a clear anti-correlation between the central gas-phase metallicity and the AGN’s Eddington ratio.

Interactive IFU Radial Profile Simulator

Compare the steep negative gradient of a normal star-forming control galaxy to the flattened and inverted gradients caused by AGN gas mixing.

IFU Spectroscopy Galaxy Evolution Spatially Resolved
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.