Event

Active Galactic Nuclei (AGNs) are galaxies currently accreting significant amounts of material onto their central super massive black holes and may mark an important phase of galaxy evolution. Many questions remain including what drives material to the centers of galaxies at the onset of accretion and how does the presence of an AGN impact star formation in the host galaxy. Understanding the relationship between galaxies and their central black holes requires the identification of AGN at a range of luminosities and redshifts using various techniques and multi-wavelengths observations. I will show how variability can be used to identify active galactic nuclei in space-based galaxy surveys. Optical variability surveys with the Hubble Space Telescope have uncovered a number of AGN in deep extragalactic fields and clusters extending to the faintest and most distant galaxy populations. Mid-infrared variability surveys using the Spitzer Space Telescope are particularly sensitive to obscured, dusty sources and may hold the key to uncovering hidden phases of galaxy/AGN evolution. These data can also address questions of accretion disk physics and the underlying cause of the variable nature of AGN.