Dartmouth Events

Abstract: It is now recognized that the energy released by accreting supermassive black holes observed as Active Galactic Nuclei (AGN) is integral in shaping the dynamics of baryons on up to cosmological scales, and AGN thus play a significant role in regulating the formation and evolution of galaxies. Studying the clustering properties of AGN reveals which environments they release this feedback energy into, testing models of AGN-galaxy coevolution and AGN structure. In this thesis, I leverage wide-area photometric and spectroscopic survey data to measure the clustering properties of various AGN samples containing millions of systems, placing tight constraints on the properties of their host dark matter halos. I first investigate the host halo properties of optically-selected red and blue quasars, finding no significant difference in their environments. Thus, quasars buried under mild dust columns likely do not represent a special phase of AGN-galaxy coevolution. On the other hand, I show that heavily obscured infrared-selected quasars occupy systematically more massive halos than their unobscured counterparts, suggesting that obscured quasars may represent a special phase of AGN-galaxy coevolution in which the black hole and galaxy are fed by common gas streams. Finally, I show that luminous low-frequency radio galaxies are hosted by massive galaxy groups over cosmic time, implying that jet-mode feedback dominates over quasar wind-mode feedback in groups and clusters.

 

Graduate Advisor: Professor Ryan Hickox