2016/09/30 by Yasaman K. Yazdi, Niayesh Afshordi · 1 citation
Earth and Planetary Sciences · Physics and Astronomy · #Accretion (finance) #Accretion disc #Active galactic nucleus #Astrophysical Phenomena and Observations #Astrophysics #Cosmic time #Eddington luminosity #Equipartition theorem #Galaxy #High-pressure geophysics and materials #Instability #Magnetic field #Mechanics #Physics #Quantum mechanics #Radiation #Radiation pressure #Radiative cooling #Radiative transfer #Star formation #Supermassive black hole #astro-ph.HE #gr-qc
paper · pdf · doi:10.3847/1538-4357/aa73d4
published as 2017, ApJ, 843, 22 · 22 pages, 12 figures. Further discussion and figure added on the thermal stability of our model in terms of S-curves of the disk. Discussions expanded on findings of simulations, as well as the predictions of our model for the hard to soft transition observed in black hole X-ray binaries. Minor other changes
openalex publication_date 2017/06/27 · arxiv created 2017/09/27 · arxiv updated 2017/09/29 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
Abstract Standard accretion disk theory predicts that the total pressure in disks at typical (sub-)Eddington accretion rates becomes radiation pressure dominated. However, radiation pressure dominated disks are thermally unstable. Since these disks are observed in approximate steady state over the instability timescale, our accretion models in the radiation-pressure-dominated regime (i.e., inner disk) need to be modified. Here, we present a modification to the Shakura & Sunyaev model, where the radiation pressure is in equipartition with the gas pressure in the inner region. We call these flows accretion in radiative equipartition (AiRE) disks. We introduce the basic features of AiRE disks and show how they modify disk properties such as the Toomre parameter and the central temperature. We then show that the accretion rate of AiRE disks is limited from above and below, by Toomre and nodal sonic point instabilities, respectively. The former leads to a strict upper limit on the mass of supermassive black holes as a function of cosmic time (and spin), while the latter could explain the transition between hard and soft states of X-ray binaries.