Analyses from 8 years of SDO/HMI data. Power spectra of even-degree sectoral Rossby modes (value mentioned in each panel) at a depth of 0.98 R_⊙ are shown by solid blue lines with circles. The Lorentzian function with a constant background, as described in Sect. 3, has been fitted to these spectra to obtain the mode frequency, line-width, and amplitude. These fits are tabulated in Table 1. The fit spectrum is shown by the solid red line.