Speaker
Description
AGN feedback plays a crucial role in regulating star formation and shaping galaxy evolution. While the role of outflows and radio jets in high-luminosity AGN such as quasars is well-documented, feedback mechanisms in lower luminosity AGN remain poorly understood. In this study, we focus on a unique sample of ten low-excitation radio galaxies (exhibiting >5 times lower radio power than their quasar counterparts) at z < 0.105. These galaxies harbor high molecular gas masses and low star formation efficiencies alongside evidence of a young stellar population formed within the past ~100 Myr. This challenges the conventional radiative and jet-mode AGN feedback paradigm, which predicts that radio jets should suppress, rather than sustain, star formation by injecting turbulence into the surrounding interstellar medium. To investigate this discrepancy, we will use near-infrared spectroscopy with Gemini/GNIRS to analyze the kinematics and excitation mechanisms of ro-vibrational H_2 emission lines, which trace warm molecular gas. These transitions provide direct insights into shock-heated gas, enabling us to assess the role of AGN-driven turbulence in regulating star formation. Additionally, we will employ emission line ratio diagnostics using MAPPINGS III shock models, comparing H_2 excitation with available CO and [Fe II] spectra to distinguish AGN-driven feedback from star formation-driven processes. This study will place low-power radio galaxies within the broader "feedback ladder," bridging the gap between feedback mechanisms in weak and powerful AGN. Through an integrated analysis of warm molecular gas and feedback diagnostics, our work will contribute to a more comprehensive understanding of how AGN jets influence star formation and galaxy evolution.
