Binary Supermassive Black Holes
When two galaxies merge, their central supermassive black holes can form a binary that gradually spirals together, emitting gravitational waves. If the pair is surrounded by gas, it may also shine across the electromagnetic spectrum. Streams from a larger circumbinary disk can feed smaller disks around each black hole, while magnetic turbulence and radiation shape the flow. The changing supply of gas, combined with orbital motion, relativistic beaming, and gravitational lensing, can leave distinctive patterns in the light we observe.
Our group uses three-dimensional general relativistic magnetohydrodynamic simulations to study these systems where gravity, magnetic fields, and radiation interact. We then use our general relativistic ray-tracing code to turn the simulated gas into predictions for images, spectra, and time-dependent light curves. By comparing how these signals change with wavelength, viewing angle, and orbital phase, we aim to distinguish genuine binaries from the ordinary variability of a single accreting black hole. These predictions can guide current multiwavelength searches and help connect future electromagnetic observations with gravitational-wave detections.