Speaker
Description
A key challenge in imaging supermassive black holes is disentangling gravitational effects from plasma physics in order to accurately determine spacetime properties, particularly black hole spin. In this Letter, we present a fully covariant and rigorous analysis of the synchrotron emission from accreting plasma in the equatorial plane in the stationary, axisymmetric, high-conductivity regime and identify for the first time a distinctive near-horizon polarization (NHP) pattern that remains robust across different flow patterns. This NHP arises from strong frame dragging near the event horizon, which induces a degeneracy among plasma flow and magnetic field configurations, yielding a polarization signature determined solely by the spacetime geometry and the observer’s inclination. The NHP thus offers a clean probe of black hole spin and other fundamental parameters. If space-based millimeter very long baseline interferometry observations can resolve synchrotron emission originating within approximately 1% of the event horizon radius, this universal polarization pattern may become observable.
| Research Area | Relativistic Astrophysics |
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