Study of Main Line Intensity Ratio of Extragalactic OH Megamasers

An important observational parameter of the OH megamasers is their 18 cm main line intensity ratio R(H)=T ₁₆₆₇ /T ₁₆₆₅. The R(H) of only 56OH megamasers from the 90 extragalactic objects is found. We have found, log R(H) is correlated with log L(OH). Using (Henkel and Wilson,1990)'s model the optical depths of 1667 MHz maser line of 56 OHmegamasers have been obtained. Here we test the hypothesis that the opacity of a maser should be related to its luminosity, for which data from the 56 OH megamaser sources can be taken. We have also found that log (-τ) is correlated with log L(OH). This revised version was published online in July 2006 with corrections to the Cover Date.