• DOI:10.1103/PhysRevD.104.124041
• Corpus ID: 238253072

Separating astrophysics and geometry in black hole images

@article{Lara2021SeparatingAA,
  title={Separating astrophysics and geometry in black hole images},
  author={Guillermo Lara and Sebastian H. V{\"o}lkel and Enrico Barausse},
  journal={Physical Review D},
  year={2021}
}

• G. Lara, S. Völkel, E. Barausse
• Published 30 September 2021
• Physics
• Physical Review D

The observation of the shadow of the supermassive black hole M87 ∗ by the Event Horizon Telescope (EHT) is sensitive to the spacetime geometry near the circular photon orbit and beyond, and it thus has the potential to test general relativity in the strong field regime. Obstacles to this pro-gram, however, include degeneracies between putative deviations from general relativity and both the description of the accretion flow and the uncertainties on “calibration parameters”, such as e.g. the mass and spin of the black hole. In this work, we introduce a formalism, based on a principal component analysis, capable of reconstructing the black hole metric (i.e. the “signal”) in an agnostic way, while subtracting the “foreground” due to the uncertainties in the calibration parameters and the modelling of the accretion flow. We apply our technique to simulated mock data for spherically symmetric black holes surrounded by a thick accretion disk. We show that separation of signal and foreground may be possible with next generation EHT-like experiments.