Disrupting the ISM: How AGN Feedback Reshapes Molecular Gas Clumpiness
Federico Esposito (Observatorio Astronómico Nacional, Madrid)
Tuesday 09/12/2025 @ 14:00, Sala Antonio Sollima (IV piano Battiferro)
The central kiloparsec of AGN host galaxies is a critical site where accretion, feedback, and galaxy-scale evolution intersect. Among the key components regulating this interplay is the dense molecular gas, which fuels both star formation and AGN activity, and constitutes the bulk of gaseous mass within the central region. In this study, we investigate how AGN feedback affects the morphology and clumpiness of molecular gas within the inner ~100 pc of local Seyfert galaxies. Using sub-arcsecond (~10 pc) ALMA observations of CO(3-2) emission from the GATOS (Galactic Activity, Torus, and Outflow Survey) sample, we analyze the spatial distribution of molecular gas and its connection to AGN luminosity and Eddington ratio. To quantify gas clumpiness, we apply a modified non-parametric structural analysis based on the CAS (Concentration, Asymmetry, Smoothness) method, adapted for molecular line emission. We find a systematic decrease in molecular gas clumpiness with increasing AGN luminosity, with a significant transition at X-ray luminosities of L_X ~ 10^{41}-10^{42} erg/s. This trend suggests that AGN-driven feedback processes, likely outflows and turbulence induced by the AGN engine, disrupt the formation of large dense gas clouds in the nuclear and circumnuclear region. Our results provide direct observational evidence that AGN feedback reshapes the molecular ISM structure on tens-of-parsec scales, potentially suppressing star formation and altering the conditions of the accreting gas. These findings provide a new perspective on how AGN feedback regulates the cold gas reservoir of galaxies, thereby impacting their evolution.