Speaker
Description
Galactic feedback processes are thought to regulate the observed co-evolution of accreting black holes and their host galaxy that is observed across cosmic time. Since molecular gas is the fuel for star formation in these galaxies, it is crucial to analyse the molecular ISM properties to understand the impact of AGN/quasars on their host galaxy. Here I will present ALMA CO observations of a sample of 41 luminous unobscured quasars at z ~ 2 from the Sloan Digital Sky Survey (SDSS). All quasars in the sample have rest-UV to optical spectra tracing ionised gas in the broad line region (e.g. CIV) and the narrow line region (e.g. [OIII]), covering the full range of outflow properties in the SDSS quasar population at these redshifts. I will present the molecular gas properties including our findings on their gas fractions which are generally lower than both inactive galaxies and red quasars/HotDOGs at similar redshifts. This may suggest an evolutionary trend in gas fractions of quasar host galaxies, from obscured and gas rich to unobscured and gas poor. I will also present a tentative correlation between the measured gas fractions and the broad-line region properties with quasars showing high CIV blueshifts (indicating stronger broad-line region winds) having higher gas fractions.
