S22B0035
S22B0035
Previous studies revealed the existence of billion-solar-mass black holes (BHs) within the first billion years of the universe. Those supermassive BHs (SMBHs) grow faster than their host galaxies compared to the correlation seen in the local universe. Their broad-line-region (BLR) gas is metal-rich up to z=7.5. However, those trends are biased towards the most luminous quasars. Our previous follow-up observations of z∼6 low-luminosity quasars from the Subaru/HSC survey revealed that the SMBH activities are generally more active than at z∼2. In S22B, we propose SWIMS spectroscopy of six low-luminosity quasars at 6.6≤ z≤ 6.9. The primary science goals is to measure the virial BH masses based on Mgii λ2798 to characterize the BH mass and Eddington ratio distributions at the highest redshift. Our targets (yHSC∼21–22 AB mag) are 1–2 magnitudes fainter than those in previous z∼7 studies; thus, our sample is complementary to theirs. Our coordinated ALMA [Cii] 158µm observations will address if the SMBH-galaxy co-evolution holds at z∼7 less affected by the luminosity bias than in previous studies. Moreover, the wide spectral coverage of SWIMS enables us to address the BLR properties at z∼7 such as the nuclear-scale outflows and the BLR metallicity.
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