"Characterizing Galactic Activity, or What Makes an AGN?"

Abstract:

Characterization of galactic activity is key for understanding the interplay of supermassive black hole growth and star-formation and their connection with the evolution of galaxies. For this reason several methods have been developed in the past 50 years, each of which is sensitive to different conditions in the nuclear regions of galaxies. I will discuss recent updates to commonly used optical and infrared diagnostics that improve their robustness, extend their applicability to all types of activity (including passive galaxies) and allow the determination of classification confidence. These improvements overcome limitations of the commonly used diagnostics and provide a more complete picture of nuclear activity accounting for measurement uncertainties and inherent limitations of our diagnostic tools. Finally I will discuss recent efforts in building galaxy catalogues with self-consistent data that can be used along with these diagnostics to characterize the hosts of transient phenomena.