Colloquium Abstract - Smith-Gandy - 2026Oct02

October 2, 2026

11:00am Mountain

Tasan Smith-Gandy (NRAO)

 

Understanding the Excess in High-Energy Ionization of Low-Metallicity Galaxies using JWST

 

Abstract

Extremely metal poor dwarf galaxies have been found to have extremely high ionization and it is unclear why. This is particularly characterized by excessive narrow emission of the He II recombination lines observed in rest-frame optical and UV spectra. Understanding where this emission comes from can provide insights into stellar evolution at low metallicities and into the mechanisms that caused galaxies like these to re-ionize the universe. In this talk, I will present our analysis and results where we aim to characterize the origin of this high energy emission using a multitude of photoionization models and compare the expected emission line strengths in the mid infrared regime to JWST data.


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