11 papers
Idealized Global Models of Accretion Disks with Strong Toroidal Magnetic Fields
Minghao Guo, Eliot Quataert, Jonathan Squire +2
We present global magnetohydrodynamic (MHD) simulations of idealized accretion disks with a strong toroidal magnetic field using an equation of state that fixes the gas thermal sca…
Time-Dilation Methods for Extreme Multiscale Timestepping Problems
Philip F. Hopkins, Elias R. Most
Many astrophysical simulations involve extreme dynamic range of timescales around 'special points' in the domain (e.g. black holes, stars, planets, disks, galaxies, shocks, mixing…
Masers and Broad-Line Mapping Favor Magnetically-Dominated AGN Accretion Disks
Philip F. Hopkins, Dalya Baron, Joanna M. Piotrowska
We present a novel and powerful constraint on the physics of supermassive black hole (BH) accretion disks. We show that in the outer disk (radii pc or $\gtrsim 10…
Thick Disks, Thin Hopes: Suppressed Capture and Merger Rates in AGN
Yashvardhan Tomar, Philip F. Hopkins, Kyle Kremer
Multiple models have been suggested over the years to explain the structure and support of accretion disks around supermassive black holes, from the standard thin thermal-pressure-…
Lagrangian versus Eulerian Methods for Toroidally-Magnetized Isothermal Disks
Yashvardhan Tomar, Philip F. Hopkins
A number of simulations have seen the emergence of strongly-toroidally-magnetized accretion disks from interstellar medium inflows. Recently, Guo et al. 2025 (G25) studied an ideal…
Cosmic Ray Perpendicular Superdiffusion and Parallel Mirror Diffusion in a Partially Ionized and Turbulent Medium
Yue Hu, Siyao Xu, Alex Lazarian +2
Understanding cosmic ray (CR) diffusion in a partially ionized medium is both crucial and challenging. In this study, we investigate CR perpendicular superdiffusion and parallel tr…