GLS periodograms of RVs and activity indicators of GJ 504: (a) SONG RVs, (b) SONG Hα indicator, (c) HARPS-N RVs, (d) HARPS-N RVs after fitting a sinusoid of P = 3.7 days, and (e) HARPS-N Hα indicator. Vertical green lines represent the stellar rotation period and its 1-day alias. The vertical orange line represents the most significant signal in the SONG RVs at 292.74 days. Horizontal dashed lines show the theoretical FAP levels of 10%, 1%, and 0.1%.