Top: frequency scan of the angular evolution of the direction toward the DM offset. R ² is the sum of the squared differences between the best-fit sinusoid of frequency ω and the angular position of the DM offset. Lower values of R ² indicate a better fit, and the deep spike to R ² < 1 at ~15 Gyr ⁻¹ corresponds to a periodicity of 69 Myr in the angular evolution. Bottom: the best-fitting sinusoid (red) overplotted on angular position of the DM offset in the last 22 outputs.