Frequency diagram (units of d^-1 on the x-axis, and ppm on the y-axis) containing all frequencies from the iterative prewhitening analysis. The centre panel shows the whole range of detected frequencies. The top panel is a zoom-in on the gravity mode region. The bottom right panel is a zoom-in on the pressure mode region (grey line is the detection threshold). The bottom left panel shows the intermediate region with two modes clearly standing out amongst the other frequencies.