¹²CO(2−1) spectra obtained at APEX for the radio galaxies NGC 1399 (top), NGC 3557 (bottom, left) and IC 4296 (bottom, right). NGC 1399 is shown for two different smoothing boxes: a velocity width of  ≈40 km s^-1 (top, left), as for the other two sources; and a wider velocity width of  ≈120 km s^-1 (top, right). Typical spectrum error bars ( and  ± Δv_res/2) are shown for reference at the systemic velocity of the galaxies. Horizontal dashed lines indicate the zero level T_a = 0.