Top panel: GLS periodogram of the SERVAL time series of GJ 143 with levels of the false alarm probability (FAP) of 10% (dotted line), 1% (dot-dashed line) and 0.1% (dashed line). Second to fourth panel: activity indicators following Zechmeister et al. (2018), H_α line index, differential line width (dLW), and chromatic index (CRX). The HARPS RVs clearly exhibit a significant peak at 35.6 d, which has no counterpart in the activity indices.