Cause of narrow-line dominance in THRILS Little Red Dots

Determine whether the narrow-line dominance of THRILS Little Red Dots is caused by enhanced host-galaxy star formation or by a clumpy broad-line-region geometry that preferentially obscures the broad-line region while allowing active-galactic-nucleus ionizing photons to reach the narrow-line region.

Background

The THRILS Little Red Dots are predominantly narrow-line dominated, unlike some active-galactic-nucleus-dominated Little Red Dots. The paper identifies two possible explanations: enhanced star formation in the host galaxy could produce the excess narrow Balmer emission, or clumpy obscuring material could hide the compact broad-line region while permitting ionizing radiation from the active nucleus to photoionize the more extended narrow-line region. The authors state that larger medium-resolution spectroscopic samples will be needed to separate these contributions.