3D volume rendering of the first global GRMHD simulation of OJ 287, a supermassive black hole binary candidate. The smaller-mass black hole is on an elliptical orbit and repeatedly plunges through the accretion disk around the larger black hole. This animation is for a mass ratio of q=0.1 and a scale height of H/r = 0.1. Here the black holes are nonspinning. Purple is cold gas, white is hot gas, and green is the highly magnetized outflow.
Poloidal and midplane slices alongside effective luminosity and accretion rate vs. time in the first global GRMHD simulation of OJ 287, a supermassive black hole binary candidate. The smaller-mass black hole is on an elliptical orbit and repeatedly plunges through the accretion disk around the larger black hole. This animation is for a mass ratio of q=0.1 and a scale height of H/r = 0.1. Here the black holes are nonspinning. The secondary induces spiral density waves in the accretion flow, leading to enhanced accretion events delayed relative to the disk impact. The disk also tilts over time due to the gravitational torque of the secondary.
3D visualization of a nonthermal flaring mechanism in black hole binaries, analogous to coronal mass ejections on the Sun. When bundles of magnetic field get accreted onto both black holes, the orbital motion causes them to twist, inflate, and then reconnect. This process taps into the orbital energy of the system to produce a burst of energy that could be observed stochastically or quasi-periodically depending on the binary separation.
Jet-jet interaction in simulations of low-angular-momentum gas accreting onto two equal-mass black holes. The left panel shows a 3D rendering of the jets while the right panel shows cross-sectional slices through the jets of plasma beta overplotted with magnetic field lines. The jets collide and form a reconnecting layer that dissipates magnetic energy and eventually causes them to merge. This process could be a powerful source of nonthermal flares in supermassive binary black hole systems.
3D visualization of a precessing jet in a binary black hole system with a 10:1 mass ratio. The precession is induced by spin-orbit coupling of the inclined orbit, which causes the primary's spin to oscillate quasi-periodically over several orbits. This particular simulation is for an initial separation of 20 gravitational radii.
Left: Poloidal slice through a wind-fed GRMHD simulation of Sagittarius A*, with the a=0.9375 spin vector pointing up. The accretion flow comes in tilted by roughly 90 degrees. Throughout the course of the simulation, there is a continued struggle between the magneto-spin torque and the incoming flow. Only during peak magnetic flux threading the black hole does the flow align. Right: 3D volume rendering of the jet in the same simulation, with spin pointing up. At most times, the jet follows the large-scale accretion flow, but during peak magnetic flux it aligns with the black hole spin. This only happens briefly, because at those moments, the jet directly pushes against its supply of magnetic flux and thus cuts off its power source.
Large-scale slice of density in simulations of magnetically modified spherical accretion (uniform initial conditions) onto a rapidly rotating black hole with a=0.9375. The black hole spin is aligned with the initial magnetic field.
Smaller-scale slices of density in simulations of magnetically modified spherical accretion (uniform initial conditions) onto a rapidly rotating black hole with a=0.9375. Left: Initial field aligned with the spin axis of black hole. Right: Initial field perpendicular to the spin axis of the black hole.
230 GHz images overplotted with polarization vectors calculated from wind-fed, 3D GRMHD simulations of Sagittarius A* with the time evolution of the 230 GHz flux and polarization fractions. The parameter βw sets the ratio between the ram pressure and the magnetic pressure of the winds. Left: βw=102. Right: βw=106. The orientation and accretion rate of the underlying simulations is set by the observed properties of Wolf-Rayet stellar winds at large radii.
Slices of density in a frame aligned with the time-averaged angular momentum of the gas in wind-fed, 3D GRMHD simulations of Sagittarius A* on a (100 M)2 scale. The parameter βw sets the ratio between the ram pressure and the magnetic pressure of the winds. Left: βw=102. Right: βw=106. Both simulations become magnetically arrested, with the strong magnetic pressure confining the gas to a relatively thin disk.
Absolute value of the rotation measure (RM) integrated from infinity in one particular 3D magneto-hydrodynamic simulation of the (assumed to be) magnetized winds of the ∼ 30 Wolf-Rayet stars in the galactic center over ∼ 1.5 kyr. RMs increase going from green to pink to white, where white includes all rotation measures ≳ the observed value for the magnetar located ∼ 0.1 pc from the black hole. RMs comparable to the magnetar's, though rare in space and time, can be produced at the present day by chance alignment between its line of sight and a shock between two winds.
Volume rendering of a 3D hydrodynamic simulation of the winds of the ∼ 30 Wolf-Rayet stars in the galactic center as they interact, shock-heat, and accrete onto Sagittarius A*, the supermassive black hole at the center of the domain. The animation lasts for ∼ 10 kyr and is on a scale of ∼ 0.5 pc.
2D slice in the plane of the sky of the density (left) and temperature (right) in a 3D hydrodynamic simulation of the winds of the ∼ 30 Wolf-Rayet Stars in the galactic center as they interact, shock-heat, and accrete onto Sagittarius A*. The ``stars'' in the simulation are source terms of energy, momentum, and mass that show up as cold, high density circular regions that frequently come into and out of view as they intersect with the central plane. The The animation lasts for ∼ 10 kyr and is on a scale of ∼ 0.5 pc.
Azimuthally averaged electron temperature in a 3D GRMHD simulation that included a separate entropy equation for the electrons based on a physically-motivated model for electron heating in turbulent, magnetized, collisionless plasmas. In this model, low β regions primarily heat electrons while high β regions primarily heat protons, resulting in the highest electron temperatures being concentrated the coronal/jet region. The animation lasts ∼ 4000 M (about a day for Sgr A*) and black lines denote b2/ρ=1 contours.
Total intensity provided by synchrotron emission and absorption as calculated from a 3D GRMHD simulation of Sgr A* including our model for self-consistently evolving the electron thermodynamics. The intensity is measured for an observer at a 45 degree tilt from the spin of the black hole (a=0.5), and is calculated at three different frequencies: 30 GHz (top), 230 GHz (top right), and in the NIR (bottom left). The 30 GHz animation is on a 200 x 200 r_g scale while the higher frequency images are on a 25 x 25 pc scale. Each animation lasts about a day.
Time variability of the spectral energy distribution produced by synchrotron emission, absorption, and Compton scattering from our 3D GRMHD + electron entropy evolution simulation of Sgr A*. Both the NIR and X-ray fluxes are highly time variable, while the radio and mm are relatively steady.