↩ 🔵 🔵 🔵 ❪✺❫ High-Energy Astrophysics Concepts ○ ❪✺_❫ Astronomical Subs ○ ❪✺_ᵢ❫ Accretion Subs ○ ❪✺_❫ Spectral Fitting Subs ○ ❪✺_ₛₛ❫ High-Energy Astrophysics Subsets ○ ❪∂_❫ High-Energy Astrophysics Subs ○ Continuous Clocking Mode ○ High-Frequency QPO (HFQPO) ○ Low-Frequency QPO (LFQPO) ○ Photon Counting Mode ○ Windowed Timing Mode ○ XSELECT ○› XSTAR ○›