BH2 - Theoretical and observational studies of astrophysical black holes |
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Speaker |
Chael, Andrew |
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Coauthors |
Chael, Andrew; Rowan, Michael; Narayan, Ramesh ; Johnson, Michael ; Sironi, Lorenzo |
| Talk Title |
The Role of Electron Thermodynamics on Event Horizon Telescope Images of Sagittarius A* |
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Abstract |
The plasma around the Galactic Center black hole Sagittarius A* (Sgr A*) is expected to have an electron temperature that is distinct from the ion temperature. Standard general relativistic magnetohydrodynamic (GRMHD) simulations cannot predict the electron temperature in two-temperature systems directly, introducing substantial uncertainty into predictions and interpretations of images observed by the Event Horizon Telescope (EHT). To explore the effects different microphysics of plasma heating have on images and variability of black holes in Low Luminosity Active Galactic Nuclei like Sgr A*, we performed two-species GRRMHD simulations including electron-ion thermodynamics and radiation. We compare the Landau-damped turbulent cascade model of electron heating used in previous works with a new prescription based on the results of particle-in-cell simulations of magnetic reconnection. The spectra of the two models are similar, but the models heated by magnetic reconnection produce variability more consistent with the level observed from Sgr A*. All models produce 230 GHz images with distinct black hole shadows consistent with early image size measurements by the Event Horizon Telescope. I will present reconstructed movies of simulated EHT data taken from these simulations and show that we are able to image a measurable photon ring in all cases, which is promising for the EHT's ability to probe GR in the near-horizon regime independently of the local plasma physics. |
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