VALIANTE, ROSAROSAVALIANTESCHNEIDER, RAFFAELLARAFFAELLASCHNEIDERGRAZIANI, LucaLucaGRAZIANIZAPPACOSTA, LucaLucaZAPPACOSTA2021-01-052021-01-0520180035-8711http://hdl.handle.net/20.500.12386/29476Supermassive black holes (SMBHs) of 10<SUP>9</SUP>-10<SUP>10</SUP> M<SUB>☉</SUB> were already in place ∼13 Gyr ago, at z > 6. Super-Eddington growth of low-mass BH seeds (∼100 M<SUB>☉</SUB>) or less extreme accretion on to∼10<SUP>5</SUP> M<SUB>☉</SUB> seeds have been recently considered as the main viable routes to these SMBHs. Here, we study the statistics of these SMBH progenitors at z ∼ 6. The growth of low- and high-mass seeds and their host galaxies are consistently followed using the cosmological data constrained model GAMETE/QSODUST, which reproduces the observed properties of high-z quasars, like SDSS J1148+5251. We show that both seed formation channels can be in action over a similar redshift range 15 < z < 18 and are found in dark matter haloes with comparable mass, ∼5 × 10<SUP>7</SUP> M<SUB>☉</SUB>. However, as long as the systems evolve in isolation (i.e. no mergers occur), noticeable differences in their properties emerge: At z ≥ 10 galaxies hosting high-mass seeds have smaller stellar mass and metallicity, the BHs accrete gas at higher rates and star formation proceeds less efficiently than in low-mass seeds hosts. At z < 10 these differences are progressively erased, as the systems experience minor or major mergers and every trace of the BH origin gets lost.STAMPAenArticle10.1093/mnras/stx30282-s2.0-85040235032000424347900074https://academic.oup.com/mnras/article/474/3/3825/46552012018MNRAS.474.3825VFIS/05 - ASTRONOMIA E ASTROFISICA