Recognizing Megamaser Galaxies from X-Ray Spectral Surveys

Our extensive archival survey of XMMNewton observations of water megamasergalaxies revealed an important result\\: we can tell apart megamaser andnonmegamaser active galaxies from the shape of their Xray spectra. Maser havemore complex Xray spectra than nonmasers. This general rule is derived from acomparison of 37 maser and 38 nonmaser sources. With our criteria, we cancharacterize 34 out of 37 sources as maser galaxies. The analysis of the 3remaining sources was inconclusive due to their lowquality archival spectra. Toconfirm our hypothesis and construct clean training sample for automated masersurveys, we propose reobservations of these 3 maser sources. Once confirmed,this result will yield strong constraints on targetselection criteria for future maser surveys. truncated!, Please see actual data for full text [truncated!, Please see actual data for full text]