2018A&A...616L...6G

We found a possible ∼1h quasi-periodic oscillation (QPO) in a ∼55ks X-ray observation of the narrow-line Seyfert 1 galaxy MCG-06-30-15 made with the XMM-Newton EPIC/pn detector in the energy range 0.3-10keV. We identify a total modulation of ∼16% in the light curve and find a ~=3670s quasi-period using Lomb-Scargle periodogram (LSP) and weighted wavelet Z-transform (WWZ) techniques. Our analyses of eight light curves of MCG-06-30-15, indicated the possible presence of an oscillation during one of them. The LSP indicates a statistically significant (~=3σ) QPO detection. A WWZ analysis shows that the signal at this possible roughly 3670s period is present, and rather persistent, throughout the observation; however, a signal around 8735 s is more persistent. We briefly discuss models that can produce X-ray QPOs with such periods in narrow line Seyfert 1 galaxies, as both other claimed QPO detections in this class of AGN had very similar periods.