Top: H i absorption profiles of 3C 58. The relative absorption of the radio continuum signal at 1420 MHz is displayed as a function of radial velocity v_LSR. Left: absorption profiles of three different positions are displayed as indicated in the bottom-right panel. Right: profile calculated using all pixels on 3C 58 with T_b ≥ 100 K. Each pixel was weighted by its intensity. Bottom: left: H i emission profiles used to determine the absorption profiles in the top left. These were averaged over the positions marked in the right panel. Right: continuum image of 3C 58 taken from the CGPS. The “on” and “off” positions used to calculate the H i absorption profiles are indicated by solid and dashed circles, respectively.