X-SHOOTER/ALMA QSOs at 5.7<~z<~7.6. II. BH masses

The black hole masses (on average, M_BH_~4.6x10^9^M_{sun}_) and accretion rates (0.1<~{lambda}_Edd_<~1.0) are broadly consistent with that of similarly luminous 0.3<~z<~2.3 quasars, but there is evidence for a mild increase in the Eddington ratio above z>~6.

Combined with deep Atacama Large Millimeter/submillimeter Array (ALMA) observations of the [CII]158um line from the host galaxies and VLT/MUSE investigations of the extended Ly{alpha} halos, this study provides fundamental clues to models of the formation and growth of the first massive galaxies and black holes. Compared to local scaling relations, z>~5.7 black holes appear to be over-massive relative to their hosts, with accretion properties that do not change with host galaxy morphologies.