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The Megamaser Cosmology Project: I. VLBI observations of UGC 3789
M. J. Reid, J. A. Braatz, J. J. Condon +3
The Megamaser Cosmology Project (MCP) seeks to measure the Hubble Constant (Ho) in order to improve the extragalactic distance scale and constrain the nature of dark energy. We are…
The kinetic temperature of a molecular cloud at redshift 0.9: Ammonia in the gravitational lens PKS1830-211
C. Henkel, J. A. Braatz, K. M. Menten +1
Using the Green Bank Telescope (GBT), we have detected the (J,K) = (1,1) to (10,10) ammonia inversion lines, up to 1030 K above the ground state, in a face-on spiral galaxy viewed…
Massive Star Formation in the Molecular Ring Orbiting the Black Hole at the Galactic Center
F. Yusef-Zadeh, J. Braatz, M. Wardle +1
A ring of dense molecular gas extending 2-7 pc orbits the supermassive black hole Sgr A* at the center of our Galaxy. Using the Green Bank Telescope, we detected water maser lines…
The Discovery of Water Maser Emission from Eight Nearby Galaxies
J. A. Braatz, N. E. Gugliucci
Using the Green Bank Telescope, we conducted a ``snapshot'' survey for water maser emission toward the nuclei of 611 galaxies and detected eight new sources. The sample consisted o…
The innermost region of the water megamaser radio galaxy 3C403
A. Tarchi, A. Brunthaler, C. Henkel +3
The standard unified scheme of active galactic nuclei requires the presence of high column densities of gas and dust potentially obscuring the central engine. So far, few direct su…
Extragalactic H_2O masers and X-ray absorbing column densities
J. S. Zhang, C. Henkel, M. Kadler +4
Having conducted a search for the 22 GHz water vapor line towards galaxies with nuclear activity, large nuclear column densities or high infrared luminosities, we present H_2O spec…