↩ 🔵 🔵 🔵 ❪∂_❫ High-Energy Astrophysics Subs ○ Channel Error (σ₍I₎≈√C₍I₎) ○￩ Chi-Squared (χ²=Σ₍C₍I₎-Cₚ₍I₎₎²∕σ₍I₎²) ○￩ᴴᴱᴬ Photon Counts (C) ○◂ Predicted Counts (Cₚ₍I₎) ○◂ Instrument Channel (I) ○◂ Observed Counts (C₍I₎=∫f₍E₎⋅R₍I,E₎⋅dE) ○￩