Growth of Massive Black Holes at High-z via Accretion Predominantly Driven by Magnetic Outflows

Abstract

Luminous quasars powered by accreting supermassive black holes (SMBHs) have been found in the early Universe at z 7.5, which set a strong constraint on both the seed black hole mass and the rapid growth of the SMBHs. In this work, we explore how the SMBHs are grown through Eddington limited accretion driven predominantly by magnetic outflows. Most angular momentum and the released gravitational energy in the disk can be removed by magnetic outflows, and therefore the mass accretion rate of the black hole (BH) can be high even if the disk is radiating at sub-Eddington luminosity. It is found that the SMBH with several billion solar masses discovered at z 7 may probably be grown through chaotic accretion predominantly driven by magnetic outflows from a stellar mass BH, when the disks are radiating at moderate luminosity (∼ 0.5 Eddington luminosity) with mild outflows. We find that most SMBHs are spinning at moderate values of spin parameter a * , which implies only a small fraction of quasars may have radio jets.

Application of the Disk Instability Model to All Quasiperiodic Eruptions

“…The main difficulty of this disk instability model for QPEs is the viscous timescale of the thin accretion disk being significantly larger than the observed periods of QPEs (e.g., Pan et al 2021Pan et al , 2022. It was suggested that the viscous timescale of a disk driven predominantly by magnetic outflows can be substantially shortened (Cao & Spruit 2013;Li & Begelman 2014;Li & Cao 2019;Feng & Cao 2021;Kaur et al 2023;Pan et al 2022;Śniegowska 2023). Pan et al (2022) constructed an instability model of the disk with magnetically driven outflows for the QPEs of GSN 069, and both its light curve and phased-resolved X-ray spectra have been fitted by their model fairly well.…”

X-ray spectral evolution in an X-ray changing-look AGN NGC 1365 with variable column density

“…The disk winds can be served as the mechanism for the variable column density and absorprtion lines (Proga & Kallman 2004;Sim et al 2010;Tombesi et al 2012;Gofford et al 2015;Miller et al 2016;Braito et al 2021), which can be driven by radiation pressure etc. (e.g., King & Pounds 2015;You et al 2016;Li & Cao 2019). The anticorrelation of N H − L 2−10keV /L Edd or N H − Γ suggest that the absorption material most possibly correlated with the accretion process (see left and right panels in Fig.…”

Probing the Growth of Massive Black Holes with Black Hole-Host Galaxy Spin Correlations

“…In this case, the distribution of BH spins is mainly determined by ∆M/M, the fractional BH mass increase in each episode. If ∆M/M 1, The disk angular momentum in each episode is large enough to drive the BH to high spin no matter what the initial spin is; while in episodes with ∆M/M 1 BH tends to spin down, because the BH mass increases linearly with the number of accretion episodes N acc while the angular momentum gain is proportional √ N acc due to the random-walk cancellation (King & Pringle 2006;King et al 2008;Wang et al 2009;Dotti et al 2013;Volonteri et al 2013;Li & Cao 2019;Zhang & Lu 2019).…”