XMM 2002 EPIC-pn spectrum of Q2237. Panel a: XMM 2002 data (black) and best-fit model (solid blue line) with Model pl_wa. The dashed blue lines indicate the UFO signatures. Panel b: XMM 2002 best-fit residuals for Model pl. Panel c: XMM 2002 best-fit residuals for Model pl_wa. The latter model self-consistently accounts for the absorption line at E_rf ≃ 7.4 keV. The data are grouped to obtain at least 20 cts/bin, with the minimum energy width set to one third of the CCD energy resolution. The best-fit parameters are summarized in Table 5. Due to background-dominated bins above 8.0 keV, we restricted the fitting to the 0.3–8 keV observed-energy range (0.8–22 keV rest-frame energy range).