2016/03/01 by Edwige Pezzulli, Rosa Valiante, Raffaella Schneider · 3 citations
Physics and Astronomy · #Accretion (finance) #Astronomy #Astrophysical Phenomena and Observations #Astrophysics #Black Holes and Theoretical Physics #Cosmology and Gravitation Theories #Physics #astro-ph.GA
paper · pdf · doi:10.1093/mnras/stw505
14 pages, 11 figures, 2 tables, accepted for publication in MNRAS
arxiv created 2016/03/01 · arxiv updated 2016/03/03 · openalex publication_date 2016/03/07 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05
The assembly of the first super massive black holes (SMBHs) at z ≳ 6 is still a subject of intense debate. If black holes (BHs) grow at their Eddington rate, they must start from ≳104 M⊙ seeds formed by the direct collapse of gas. Here, we explore the alternative scenario where ∼100 M⊙ BH remnants of the first stars grow at super-Eddington rate via radiatively inefficient slim accretion discs. We use an improved version of the cosmological, data-constrained semi-analytic model GAMETE/QSOdust, where we follow the evolution of nuclear BHs and gas cooling, disc and bulge formation of their host galaxies. Adopting SDSS J1148+5251 (J1148) at z = 6.4 as a prototype of luminous z ≳ 6 quasars, we find that ∼80 per cent of its SMBH mass is grown by super-Eddington accretion, which can be sustained down to z ∼ 10 in dense, gas-rich environments. The average BH mass at z ∼ 20 is MBH ≳ 104 M⊙, comparable to that of direct collapse BHs. At z = 6.4 the AGN-driven mass outflow rate is consistent with the observations and the BH-to-bulge mass ratio is compatible with the local scaling relation. However, the stellar mass in the central 2.5 kpc is closer to the value inferred from CO observations. Finally, ∼20 per cent of J1148 progenitors at z = 7.1 have BH luminosities and masses comparable to ULAS J1120+0641, suggesting that this quasar may be one of the progenitors of J1148.