Multi-frequency emission Modeling of accreted Black Hole Plasma with Semi-analytical descriptions for next generation Event Horizon Telescope (EHT) observations

Since the announcement of the first black hole image, the Event Horizon Telescope (EHT) collaboration has been working to perform data analysis in hopes to improve future observations (i.e. ‘next generation’ or ngEHT). In the image produced by EHT using the VLBI experiment, the plasma accretion disk can be seen lensed around the black hole. In this project, accreted plasma is modeled using semi-analytical descriptions rather than the computationally demanding 3D General Relativistic Magneto-HydroDynamic (GRMHD) simulations. Using the geodesics for rotating/non-rotating black holes and General Relativistic Radiative Transfer (GRRT), different semi-analytic simulations are developed including: reverse ray tracing (Python ODE solver), thin disk models, Radiatively Inefficient Accretion Flow (RIAF) models and orbiting plasma hot spots. These simulations, combined with synthetic EHT observational data, explore properties of the black hole by varying the spin parameter, inclination angle of the observer, and observational frequency (43e9, 86e9, 120e9, 230e9, 345e9, 680e9, 1000e9 in GHz). There is also exploration of thermal and nonthermal particle distributions, as well as translations to Fourier space. Results from these models can be used to probe for new array configurations for ngEHT imaging.