Effect of the disk surface density on the flare, for the θ = 135^∘ collision. (Left) Excess luminosity ΔL, measured at y/r = −1.2 below the midplane after subtracting the reference run without a star, for a disk with 100 ×  the fiducial surface density (100 Σ, blue solid) and for the standard disk with its ΔL multiplied by 100 (red dashed). The time axis begins at t = 0.15 T₀ to exclude the initial relaxation transient. Filled circles mark the light-curve peaks. (Right) Excess spectra Δ(νL_ν) at those two peaks, with best-fitting single-temperature blackbodies (dotted) at T_bb = 1.3 × 10⁶ K (109 eV) and T_bb = 4.0 × 10⁵ K (34 eV), respectively.