Dependence of the photon ring spectral feature on inclination and electron density in a RIAF model of Sgr A*. Left: 230 GHz images of the same model at 30° and 70° inclination, with a fixed peak number density of 3 × 10⁸ cm⁻³. Middle: spectral index maps at 230–235 GHz at each inclination. Right: spectra of the decomposed model at each inclination, varying the electron number density. The black star indicates the 230 GHz, 2.4 Jy value at the density used in the left figures.