Spectra of the four 22 GHz water megamasers detections. Velocities are in the kinematic local standard of rest (LSR) frame and use the optical convention. Recession velocities, V_sys, are adopted from NED. The channel spacing is 0.3 km s^-1. The uncertainty of the flux density scale is ≤15%. Top left: maser features towards possible Sy 2 galaxy 2MFGC 13581 are typical of masing sub-parsec accretion disks around AGN. Top right: IRAS 17526+3253 (UGC 11035) is an OH KM galaxy and has narrow 360 L_⊙ water masers. Bottom left: NGC 4261 (3C 270; twin jet, torus) shows deep H  I absorption at 2260 km s^-1 (right inset) and deep 6 GHz OH absorption at 2100–2400 km s^-1 (left inset) against the counter-jet (insets adopted from van Langevelde et al. 2000; Impellizzeri 2008). The broad H₂O MM feature is slightly redshifted with respect to the systemic velocity. Bottom right: IRAS 20550+1656 (II Zw 96) is an OH MM object and has a tentative H₂O MM detection at 5σ after 16-channel Gaussian smoothing (inset). Fits for two main features that are symmetric around V_sys are overlaid, together with two narrower “suggestive” features that are also symmetric but otherwise similar to the noise peaks even after stronger smoothing.