H-AMR FORGE'd in FIRE. I. Magnetic State Transitions, Jet Launching, and Radiative Emission in Super-Eddington, Highly Magnetized Quasar Disks Formed from Cosmological Initial Conditions

Quasars are powered by supermassive black hole (SMBH) accretion disks, yet standard thin disk models are inconsistent with many observations. Recently, P. F. Hopkins et al. simulated the formation of a quasar disk feeding an SMBH of mass M = 1.3 × 10⁷ M_⊙ in a galaxy. The disk had surprisingly strong toroidal magnetic fields that supported it vertically from gravity and powered rapid accretion. What feedback can such a system produce? To answer this, we must follow the gas to the event horizon. For this, we interpolated the quasar into the general-relativistic radiation magnetohydrodynamics code H-AMR and performed 3D simulations with BH spins a = 0 and a = 0.9375. This remapping generates magnetic monopoles, which we erase using a novel divergence cleaning approach. Despite the toroidal magnetic field's dominance at large radii, vertical magnetic flux builds up near the event horizon, leading to a magnetic state transition within the inner 200 gravitational radii of the disk. This powers strong winds and, for spinning BHs, relativistic jets that can spin down the BH within 5−10 Myr. Sometimes, vertical magnetic fields of opposite polarity reach the BH, causing a polarity inversion event that briefly destroys the jets and, possibly, the X-ray corona. These strong fields power accretion at rates 5× the Eddington limit, which can double the BH mass in 5–10 Myr. When a = 0.9375 (a = 0), the energy in mechanical outflows and radiation equals about 60% (10%) and 100% (3%) of the accreted rest mass energy, respectively. Much of the light escapes in cool, ≳1300 au photospheres, consistent with quasar microlensing and spectral energy distributions.