Signal-to-noise ratio of the ¹²CO J = 2−1, ¹³CO J = 2−1, and ¹³CO J = 6−5 spectra in the inner 1″.0 and 1″.5 for LkCal5 (left) and HD 169142 (right), resp. The systematic velocity is indicated with the vertical red line. The vertical black lines indicate the maximal velocities where emission at that radius is expected based on the Keplerian velocity profile. We note the difference in horizontal axes.