High redshift quasar abundances and environments connecting black hole and host galaxy evolution.

摘要

I examine the evolutionary relationship between quasar host galaxies and supermassive black holes (SMBHs). Current models predict an evolutionary sequence where SMBHs become active as quasars some time after major star formation episodes in their host galaxies. The quasars may in turn produce outflows that quench the host galaxy star formation. However, concrete mechanisms that explain the interactions between the host galaxy and the SMBH remain poorly understood. I constrain this host galaxy-SMBH relationship through the examination of host galaxy star formation and quasar outflow phenomena. Specifically, I measure the quasar gas-phase metallicity, which indicates the past level of star formation in the host galaxies, using emission and absorption lines in quasar spectra. I examine, in particular, the nature and origin of narrow absorption lines (NALs), which sometimes form in quasar outflows, and which provide valuable information on the gas kinematics, column densities and ionizations in a variety of quasar environments.;Current quasar host galaxy-SMBH evolution scenarios suggest that host galaxy star formation rates should typically decrease across quasar lifetimes. I examine the relationship between past and ongoing star formation in quasar hosts by, for the first time, comparing emission line metallicity in redshift 2--4 quasars to far-infrared luminosity, which indicates the ongoing star formation rate in the host galaxy. I measure super-solar metallicities, regardless of the ongoing star formation rates.;I measure covering fractions and profile widths to determine the origins of every individual NAL in a comprehensive NAL survey, the first of its kind, covering the full range of quasar environments for 24 quasars at redshifts 2--4.7. I estimate that 20% of all these NALs are intrinsic to the quasar environment, and up to 77% of these likely formed in quasar outflows. I measure metallicities for the NALs that I find to be intrinsic, and find a surprising range of metallicities of 0.03 Z⊙ ≤ Z ≤∼ 20 Z⊙ . The high metallicities are similar to those derived for other quasars at similar redshifts and luminosities and are consistent with current evolution scenarios. The wide range in metallicities suggests that the data provide the first ever compilation of gas phase metallicities across the full range of near-quasar environments.