Spectral energy distribution of OH megamaser galaxies

The properties of OH megamaser galaxies are analyzed. Using the linear dependence of L ^sub OH^ on L ^sub FIR^ and the luminosity function for IR galaxies, the expected number of megamasers is estimated. From observational data at many frequencies (from radio waves to x rays), the spectral energy distributions (SEDs) of 16 objects have been plotted and studied. The SEDs of megamasers have the same form from the radio to the x ray range. Considerable emission is observed in the 3 µm range, which evidently indicates the presence of red giants and supergiants in these objects. Possible reasons for the departure of the slope of the dependence of L ^sub OH^ on L ^sub FIR^ from unity are considered. The assumption that collisional pumping may play an important role in the inversion of ground levels of the OH molecule and the saturated gain mechanism in megamasers is confirmed.[PUBLICATION ABSTRACT]