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Quasars Probing Quasars: the Circumgalactic Medium Surrounding z ~ 2 Quasars


Marie Lau (UCSC)

December 12, 2017 @ 12:00 PM - 1:00 PM

Understanding the gaseous halo surrounding a galaxy is an integral part to understanding galaxy evolution. The z ~ 2 universe is interesting as this is when universal star formation and AGN activity peak. My work is part of the Quasars Probing Quasars survey, which is nearing conclusion, and have employed 17 optical and near-IR instruments on 8 m class telescopes. Quasars Probing Quasars is designed for studying massive galaxy formation and quasar feedback. I use background quasar sightlines that pass close to foreground quasars to study the circumgalactic medium of quasar-host galaxies in absorption. In present results on the statistical and physical properties of the absorbing gas clumps. Compared to coeval star-forming galaxies, the circumgalactic medium surrounding quasars is more massive, more enriched, and exhibits more extreme kinematics.  These results pose challenges for cosmological hydrodynamic simulations. Then I present evidence that the ionizing radiation from the quasar is anisotropic or intermittent and that the gas is not in inflow. Finally I will discuss future studies of (1) joint constraints from absorption and emission on the gaseous environments of quasars using IFU; (2) other science goals that can be facilitated using the databases and analysis tools already built, such as going to the lower redshift universe for better constraining AGN feedback.