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The central focus of my research is studying the co-evolution of galaxies and their supermassive black holes (SMBH). When these black holes grow through mass accretion, they become visible as powerful active galactic nuclei (AGN). Although AGN have been studied for more than half a century, their potential importance to the evolution of galaxies has only recently become evident. Observations over the past decade have revealed that a tight correlation exists between the mass of a galaxy’s spheroid component, or central ‘bulge’, and the black hole at its center. This correlation suggests that the formation and growth of SMBH is intimately linked to the growth of their host galaxies. Current theories propose that this link is forged, in part, by the energy released during an AGN phase. Computer simulations have shown that a sufficiently energetic AGN can drive outflows that halt the accretion of gas onto the central black hole, while simultaneously acting to suppress the surrounding galaxy’s star formation activity. In this way, AGN can self-regulate the growth of both supermassive black holes and their host galaxies. This scenario has been widely adopted such that most cosmological models of galaxy evolution now invoke feedback from an AGN as the primary mechanism to terminate the star formation activity of massive galaxies. In fact, without the energy input from AGN, many models fail to reproduce fundamental properties of galaxies. Despite this emerging picture, several major questions remain about AGN and their potential impact on galaxy evolution. What mechanisms fuel black hole growth and turn a dormant black hole into an AGN? What is the precise nature of AGN feedback? What role do AGN play in giving rise to the first generation of quenched galaxies? These issues are among the key unanswered questions in Astrophysics today. To answer these questions, my work uses multi-wavelength observations ranging from the X-ray to the Infrared to study the morphologies, stellar populations and environments of galaxies that host AGN. My research makes use of NASA’s Great Observatories (Chandra, Hubble, Spitzer and Webb), as well as large spectroscopic datasets collected with the Keck telescopes. I am currently involved in several large multi-wavelength surveys, including the CEERS and CANDELS collaborations. The ultimate goal of my work is to construct an integrated model for the triggering of AGN activity, the quenching of star formation, and the structural evolution of galaxies in the early Universe. Please see my publications page for more details or check out my blog posts on the CANDELS blog for more information on AGN. |
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