AN ANALYTIC MODEL FOR MAGNETICALLY-DOMINATED ACCRETION DISKS

Philip F. Hopkins, Jonathan Squire, Eliot Quataert, Norman Murray, Kung Yi Su, Ulrich P. Steinwandel, Kyle Kremer, Claude André Faucher-Giguère, Sarah Wellons

Research output: Contribution to journalArticlepeer-review

Abstract

Recent numerical cosmological radiation-magnetohydrodynamic-thermochemical-star formation simulations have resolved the formation of quasar accretion disks with Eddington or super-Eddington accretion rates onto supermassive black holes (SMBHs) down to a few hundred gravitational radii. These “flux-frozen” and hyper-magnetized disks appear to be qualitatively distinct from classical α disks and magnetically-arrested disks: the midplane pressure is dominated by toroidal magnetic fields with plasma β ≪ 1 powered by advection of magnetic flux from the interstellar medium (ISM), and they are super-sonically and trans-Alfvénically turbulent with cooling times short compared to dynamical times yet remain gravitationally stable owing to magnetic support. In this paper, we present a simple analytic similarity model for such disks. For reasonable assumptions, the model is entirely specified by the boundary conditions (inflow rate at the BH radius of influence [BHROI]). We show that the scalings from this model are robust to various detailed assumptions, agree remarkably well with the simulations (given their simplicity), and demonstrate the self-consistency and gravitational stability of such disks even in the outer accretion disk (approaching the BHROI) at hyper-Eddington accretion rates.

Original languageEnglish (US)
JournalOpen Journal of Astrophysics
Volume7
DOIs
StatePublished - 2024

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics

Keywords

  • accretion, accretion disks
  • galaxies: active
  • galaxies: evolution
  • galaxies: formation
  • quasars: general
  • quasars: supermassive black holes

Fingerprint

Dive into the research topics of 'AN ANALYTIC MODEL FOR MAGNETICALLY-DOMINATED ACCRETION DISKS'. Together they form a unique fingerprint.

Cite this