↩ 🔵 🔵 🔵 ❪∂❫ High-Energy Astrophysics Math ○ ❪∂₁❫ Astronomical Functions ○ Instrumental Response (R₍I,E₎) ○◂ Model Spectrum (f₍E, p1, p2, …₎) ○◂ Point Spread Function ○◂ᴴᴱᴬ Source Spectrum (f₍E₎) ○◂