Supermassive black holes (SMBHs) of 109-1010Mâwere already in place ~13 Gyr ago, at z > 6. Super-Eddington growth of low-mass BH seeds (~100Mâ) or less extreme accretion on to~105Mâseeds 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 à 107Mâ. 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.
Chasing the observational signatures of seed black holes at z > 7: Candidate statistics
Schneider, RaffaellaWriting – Original Draft Preparation
;Graziani, LucaWriting – Original Draft Preparation
;
2018
Abstract
Supermassive black holes (SMBHs) of 109-1010Mâwere already in place ~13 Gyr ago, at z > 6. Super-Eddington growth of low-mass BH seeds (~100Mâ) or less extreme accretion on to~105Mâseeds 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 à 107Mâ. 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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.