TSI Seminar - Gibwa Musoke
Gibwa Musoke
(CITA)
Feb 11, 2025 3:30 PM
Location: Bell Room (Rutherford 103)
TSI Seminar
Black hole X-ray binaries (and Active Galactic Nuclei) transition
through a series of accretion states in a well-defined order. The
accretion states, each associated with different luminosities, spectral
characteristics and outflow properties, are thought to be triggered by
physical changes in the accretion disk around the central black hole. An
initially hot and thick accretion disk is thought to transition into a
disk that is cool and thin, though the mechanisms behind this transition
remain highly debated.
The hard intermediate accretion state present in the midst of a state
transition is thought to be associated with the presence of both a hot,
thick component– termed the corona, along with a cool and thin component
of the accretion flow. The details concerning the geometry of the disk
in the hard intermediate state are not agreed upon and numerous models
have been proposed: In the “truncated disk” model, the accretion flow is
thick and hot close to the black hole, while the outer regions of the
flow are thin and cool. There are many open questions concerning the
nature of truncated accretion disks: Which mechanisms generate the
truncated disk structure? What sets the radius at which the disk
truncates? How is the corona formed and what is its geometry? In this
talk I present the first high-resolution 3D General Relativistic
Magneto-Hydrodynamic (GRMHD) simulations modelling the self-consistent
formation of a truncated accretion disk around a black hole.
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