Affiliation: Center for Astrophysics | Harvard & Smithsonian

Contribution: Poster

Title: Separating Star Formation, Active Galactic Nuclei, and Shocks in Galaxies

Abstract: The cosmic evolution of galaxies and supermassive black holes (SMBHs) is believed to be correlated through interlinked physical processes. However, two aspects of the galaxy-BH correlation remain unclear: the fueling of actively accreting black holes (called Active Galactic Nuclei or AGNs) and the physical process of AGN feedback. Previous attempts to answer these questions using single-aperture spectra of galaxies have fallen short, as they can only consider the dominant excitation source in the spectrum and cannot rule out the involvement of other excitation sources such as supermassive black holes, star formation, and shock excitations. Here, we present a solution for the mixing mechanisms in galaxy spectra analysis by building a new theoretical three-dimensional (3D) diagram to simultaneously separate star formation, AGN, and shocks in galaxies with integral field spectroscopy (IFU) data. This new 3D diagram incorporates the most up-to-date and self-consistent theoretical models for HII regions, AGN narrow-line regions, and the time-dependent shocks and precursor models. The inclusion of theoretical models in the new 3D diagram independently constrains the parameter space for each mechanism and provides information on the gas metallicity, ionization states, and shock velocity along with the separation. By applying this new 3D diagram, researchers can obtain detailed maps of the mechanism distribution, gas metallicity, and ionization states for individual galaxies. This new 3D diagram shows a remarkable ability to detect hidden shocks in nearby Seyfert galaxies, including but not limited to NGC 424, NGC 1365, NGC 7496, and NGC 1566.

This contribution can be found in the Poster Hall.