A new diagnostic to separate line emission from star formation, shocks, and AGNs simultaneously in IFU data

Abstract

ABSTRACT In the optical spectra of galaxies, methods for the separation of line emission arising from star formation and an additional hard component, such as shocks or active galactic nuclei (AGNs), is well-understood and possible with current diagnostics. However, such diagnostics fail when attempting to separate and define line emission which arises from shocked gas, and that arising from AGNs. We present a new three-dimensional diagnostic diagram for integral field unit data which can simultaneously separate the line emission amongst star formation, shocks, and AGNs within a galaxy. We show that regions we define as AGN-dominated correlate well with the hard X-ray distribution in our test case NGC 1068, as well as with known regions of AGN activity in NGC 1068. Similarly, spaxels defined as shock-dominated correlate strongly with regions of high-velocity dispersion within the galaxy.