Left panel: modified Fourier (with its spectral window on top), AOV, and conditional entropy periodograms considering all Swift data. Middle panel: modified Fourier periodograms for different sets of Swift data. Right, top panel: zoom on the low-frequency content of the modified Fourier periodogram calculated on all Swift data. Right, bottom panel: modified Fourier periodogram, with its spectral window, for Swift and XMM-Newton-pn data combined. The pn data were arbitrarily scaled by a factor 0.1. The two known periods (see also Sect. 4) are shown by dotted lines: green for 2366 d and red for 6.6 d.
Current usage metrics show cumulative count of Article Views (full-text article views including HTML views, PDF and ePub downloads, according to the available data) and Abstracts Views on Vision4Press platform.
Data correspond to usage on the plateform after 2015. The current usage metrics is available 48-96 hours after online publication and is updated daily on week days.
Initial download of the metrics may take a while.