Jets from SANE super-Eddington accretion discs: morphology, spectra, and their potential as targets for ngEHT

We present general relativistic radiation magnetohydrodynamics (GRRMHD) simulations of super-Eddington accretion flows around supermassive black holes (SMBHs), which may apply to tidal disruption events (TDEs). We perform long duration ($t\ge 81,200\, GM/c^3$) simulations that achieve mass accretion rates ≳11 times the Eddington rate and produce thermal synchrotron spectra and images of their jets. Gas flowing beyond the funnel wall expands conically and drives a strong shock at the jet head while variable mass ejection and recollimation, along the jet axis, results in internal shocks and dissipation. Assuming the ion temperature (T_i) and electron temperature (T_e) in the plasma are identical, the radio/submillimetre spectra peak at >100 GHz and the luminosity increases with BH spin, exceeding $\sim 10^{41} \, \rm {erg\, s^{-1}}$ in the brightest models. The emission is extremely sensitive to T_i/T_e as some models show an order-of-magnitude decrease in the peak frequency and up to four orders-of-magnitude decline in their radio/submillimetre luminosity as T_i/T_e approaches 20. Assuming a maximum VLBI baseline distance of 10 Gλ, 230 GHz images of T_i/T_e = 1 models shows that the jet head may be bright enough for its motion to be captured with the EHT (ngEHT) at D ≲ 110 (180) Mpc at the 5σ significance level. Resolving emission from internal shocks requires D ≲ 45 Mpc for both the EHT or ngEHT.