Simulating Neutron Star Binary Merger Remnant Disks and Tilted Thin Disk

Project Description

In August 2017, gravitational waves (GWs) from a merger of binary neutron stars were detected for the first time, accompanied by optical/UV electromagnetic “kilonova” emission (due to the radioactive decay of r-process elements synthesized in the ejecta) and by a radio, x-ray, and gamma-ray flare (due to a jetted outflow). To meaningfully interpret this exciting discovery and make predictions for future GW detections and their electromagnetic counterparts, Tchekhovskoy’s team will simulate the long-term evolution of a magnetized turbulent merger remnant accretion disk and its outflows. Summit will also allow the team to carry out the long- waited, truly thin tilted disks simulations with h/r = 0.02 to determine whether inner regions of such disks align with the black hole by the purely general relativistic Bardeen-Petterson effect. Both goals push the limits of physics and computation in preparation for future exascale systems and will lead to a better understanding of magnetized black hole accretion systems, especially in regards to recent paradigm-shifting results obtained by the team that suggest that at large tilt values, the disk breaks or tears apart, potentially leading to a substantially higher disk radiative efficiency accompanied by flaring events.