Extended Data Fig. 4: Fits to the quiescent spectrum of AT2019qiz and the nearby SE source.
From: Quasi-periodic X-ray eruptions years after a nearby tidal disruption event
Shaded regions show 90% confidence intervals. a, Fit to the SE source from Chandra (first and third epochs). The data are best fit with a power law with Γ = 1.8 ± 0.5. b, Fit to the quiescent spectrum from Swift/XRT. This includes flux from both sources. We fit with a power law plus a thermal disk model including colour correction (tdediscspec), using the posteriors from the SE source as the priors on the power-law component. The SE source clearly dominates the count rate above ≃1 keV. Below this, the spectrum is well fit by the thermal disk with peak temperature kTp = 67 ± 10 eV, similar to other QPE sources during their quiescent phases1,3 and similar to X-ray-detected TDEs44. The SE source contribution is shown in blue. c, Fit to the X-ray spectrum during the initial phase of the TDE optical component (MJD 58714 to 59000) using the temperature and power-law slope from panels a and b. The spectrum is consistent with emission from the SE source, with no statistically significant contribution from AT2019qiz.
