Figure 2 : Polarimetry periodograms.

From: Polarimetric evidence of a white dwarf pulsar in the binary system AR Scorpii

Figure 2

Amplitude spectra of the Stokes U (left) and Q (right) parameters from the two combined nights of HIPPO data, through the ‘clear’ filter (350–900 nm). The bottom two panels cover frequencies from 0–40 mHz (periods <25 s), while the top eight panels show the fundamental and harmonic frequencies in more detail. The dashed vertical lines mark the beat and spin frequencies (ω − Ω and ω, respectively) and their first, second and third harmonics.