Electromagnetic radiation signatures from turbulent reconnection in black hole accretion flows

The extreme environment close to supermassive black holes creates an exquisite cosmic laboratory where strong gravity, plasma-physical effects, particle acceleration, and radiation all leave their mark. With polarimetric measurements by instruments such as the Event Horizon Telescope and GRAVITY, we are approaching an era of high-precision black hole astrophysics, where the state-of-the-art modeling efforts are challenged. The research outlined in this proposal aims to utilize all facets of modeling the supermassive black hole environment, which rely on numerical simulations of the hot, ionized gas known as plasma that is accreted by the central object. In essence, there are two well-established methods for describing the plasma condition in these systems. First, one utilizes collisional, fluid-based methods to describe the global dynamics of the accretion system. Second, with collisionless, particle-based methods, one describes the micro-physical effects, such as particle acceleration and heating. While the former suffers from over-simplifying assumptions, the latter is computationally extremely expensive. Therefore, to benefit from the strengths of both methods, I aim to implement and investigate improved sub-grid, small-scale physics in global simulations of the accretion system, which will be compared directly with observations observed at radio, near-infrared, X-ray, and the most energetic gamma rays as constrained by, e.g., the Event Horizon Telescope.

Keywords:High-energy astrophysics, Radiative transfer

Disciplines:Computational physics