Mean discrete Fourier periodograms over the full line profile variations for the Mg ii 4481 Å (top) and the He i 6678 Å (bottom) absorption lines in the Narval spectroscopy, determined with the pixel-by-pixel method. The rotation frequency and the second harmonic of the rotation frequency are indicated in blue. The found pulsation-mode frequency in the Mg ii line is indicated in red. Strong 1  d^-1 aliasing frequency peaks are present in the periodograms.