Results from the optical monitoring of γ Cas. Left panel illustrates the EWs of various prominent lines as a function of time, whilst the right panel yields the RV separation of the double-peaked profiles. The dashed vertical lines in the EW plots correspond to the dates of the new XMM-Newton observations. Filled and open symbols identify TIGRE data and spectra collected by co-author JGF, respectively. Asterisks (Hα and He I λ 6678 panels) correspond to Aurélie data, and four-point stars (Hα panel) refer to BeSS archival spectra.