The Discovery of H 2 O Maser Emission in Seven Active Galactic Nuclei and at High Velocities in the Circinus Galaxy

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Abstract
We report the discovery of H2O maser emission at 1.35 cm wavelength in seven active galactic nuclei (at distances of up to 80 Mpc) during a survey conducted at the 70 m diameter antenna of the NASA Deep Space Network near Canberra, Australia. The detection rate was ~4%. Two of the maser sources are particularly interesting because they display satellite high-velocity emission lines, which are a signature of emission from the accretion disks of supermassive black holes when seen edge-on. Three of the masers are coincident, to within uncertainties of 02, with continuum emission sources that we observed at about λ = 1.3 cm. We also report the discovery of new spectral features in the Circinus galaxy H2O maser that broaden the known velocity range of emission therein by a factor of ~1.7. If the new spectral features originate in the Circinus accretion disk, then molecular material must survive at radii ~3 times smaller than had been believed previously (~0.03 pc or ~2 × 105 Schwarzschild radii).
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