Extended Data Fig. 6: QPE phase-resolved spectroscopy.
From: Nine-hour X-ray quasi-periodic eruptions from a low-mass black hole galactic nucleus
QPE spectral evolution throughout the cycle. a, b, Temperature (a) and 0.2–2 keV luminosity (b) of the variable blackbody component throughout the QPE cycle (see Extended Data Table 3b). In a, the shaded area represents the constant temperature of the stable (likely outer) accretion disk. c, d, The corresponding SED evolution (where FE is the model flux spectrum): the best-fitting model during the QPE rise from quiescence (Qpre) to QPE peak (P) (c), and during the QPE decay from peak (P) back to quiescence (Qpost) (d). The model predicts no variability below 0.1 keV, in line with the expectations based on Extended Data Fig. 5a, b. In a and b, errors represent the 90% confidence intervals as obtained from X-ray spectral fits to the phase-resolved spectra (some of the error bars being smaller than the symbol size).