Quasi-Periodic Oscillation · X-ray heartbeat
unseel.com · van der Klis 1985 · 3:2 HFQPO · νK ≈ 220 Hz · 10 M☉/M
Q = ν₀/Δν
HFQPO 3 : 2
phase
X-ray flux / horizon
Disk + Keplerian orbit
Power spectrum
Spin axis / precession
Unseel.com · Quasi-Periodic Oscillation