Period search results and pulse profile of EP/FXT data. Main panel: Period-searching results using the $Z_2^2$ test in energy bands of 0.3−2 keV (solid black line) and 2−6 keV (solid red line). The error on the best period value is estimated to be 2 s (calculated using the bootstrap method). The dotted horizontal represents the 4σ significance level obtained using the bootstrap method. We mark the negative and positive beat period with a dashed black line and mark the optical spin period (Potter et al. 2024) with a dotted red line. Inset: 0.3 − 2 keV pulse profile folded on the period of 231 s.