The role of dissipative physics on electromagnetic observables of black hole accretion

The Event Horizon Telescope (EHT) has released analyses of horizon-scale images of two supermassive black holes: Messier 87* and Sagittarius A*. Numerical fluid simulations of black hole accretion form a cornerstone of these analyses. Synthetic images and spectra generated from these simulations help infer properties of the accreting plasma and the underlying spacetime. The canonical library of fluid simulations used in the EHT pipeline comprises ideal general relativistic magnetohydrodynamic (GRMHD) simulations which treats the accreting plasma as a single-temperature, thermal fluid. However, the environment around EHT targets is believed to consist of a hot, Coulomb-collisionless plasma where dissipative processes like heat conduction and viscosity can alter the flow dynamics, and in turn the synthetic observations. In this talk I will present a model developed by members of our group that incorporates these additional physical processes and discuss some of its salient features. I will briefly highlight the associated numerical and computational challenges and present some results from our library of dissipative fluid simulations of black hole accretion.