S20B0114abst
S20B0114
Previous studies of luminous z >∼ 6 quasars revealed that there exist gigantic supermassive black holes (SMBHs) with MBH =109−10 M⊙ accreting at the Eddington limit. Those SMBHs grow faster than their host galaxies compared to the SMBH-bulge mass relation known in the local universe. However, we found that sub-Eddington SMBHs are common in the lower-luminosity range (Lbol<∼1047 erg s−1), whose mass accretion has already been switched to quiescent phase, as well as their host star formation. Therefore, the extreme properties of z>6 quasars reported in the literature are strongly biased towards the most luminous population. This proposal is the second part of our project aiming at constructing a well-defined statistical sample of quasars whose SMBH mass are measured with Mgiiλ2798. We selected two low-luminosity quasars at z∼6.4 remaining to be observed in NIR. With 19 quasars from the literature and our past observations, we will give a constraint on the SMBH mass (and Eddington ratio) distribution by disentangling the updated quasar luminosity function. Our ALMA projects will investigate the host galaxy properties of the same targets to address the build-up of the SMBH-galaxy co-evolution at high redshift.
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