The properties of a sample of extragalactic H 2 O maser sources over a wide spectral range are discussed.Based on a sample of 81 maser galaxies it is shown that mega-and kilomasers have completely different properties. In particular, for megamasers the strongest observed relationships are between the parameters of the H 2 O line and the mass of the galactic nucleus, while the parameters of the line are uncorrelated with the x-ray, infrared, and radio emission. A weak correlation between megamaser emission and the surface (column) density of hydrogen is observed. As for kilomasers, their H 2 O luminosity depends weakly on the x-ray emission, although in the case of soft x rays this dependence is significant. The H 2 O luminosity of kilomasers is moderately correlated with the infrared and radio continuum luminosities, but the line parameters are independent of the mass of the nucleus and the surface density of hydrogen. 330 central region (N H > 10 24 cm -2 ) [2,4,5]. X-ray radiation from the central part of a galaxy can heat a circumnuclear molecular cloud and stimulate water maser emission [6]. In that case, we may expect a relationship between the maser and x-ray emission. Furthermore, if megamaser emission is related to the activity of the nucleus, then a correlation between maser emission and the mass of the nucleus of a galaxy is to be expected [7,8].Maser emission originates from a central part of a galaxy of size 1 pc or smaller. Megamasers are subdivided morphologically into three major groups: (a) disk masers, where the sources of the radiation are formed by a presumed accretion disk (e.g., NGC 4258); (b) jet masers, which lie along a stream emerging from the center of the galaxy (e.g., Mrk 348); and, (c) outflow masers, which lie along outflows from the nucleus (e.g., Circinus). This morphological classification is based primarily on VLBI observations [9] and as well on the spectral features of the maser emission.A slight correlation has been observed between maser and x-ray emission [7]. If the maser emission originates in an accretion disk, then there must be a correlation between the maser and x-ray emission, since accretion disks are strong x-ray sources; hence, this question is of some interest. Studies of the relationship between maser emission and the

The properties of a sample of extragalactic OH maser sources over a wide spectral range are discussed.Based on a sample of 22 maser galaxies it is shown that OH, HCN, and x-ray emission are closely related. On the other hand, these emissions depend on the mass of the galactic nucleus. It is shown that the broadening of the OH emission line is caused by the rotation of the circumnuclear disk, dense regions of which serve as the sources of OH and HCN emission. X-ray heating can excite OH and HCN molecules.