The Megamaser Cosmology Project. XI. A Geometric Distance to CGCG 074-064

As part of the survey component of the Megamaser Cosmology Project, we have discovered a disk megamaser system in the galaxy CGCG 074-064. Using the Green Bank Telescope and the Very Large Array, we have obtained spectral monitoring observations of this maser system at a monthly cadence over the course of two years. We find that the systemic maser features display line-of-sight accelerations of similar to 4.4 km s(-1) yr(-1) that are nearly constant with velocity, while the high-velocity maser features show accelerations that are consistent with zero. We have also used the High-Sensitivity Array to make a high-sensitivity very long baseline interferometric map of the maser system in CGCG 074-064, which reveals that the masers reside in a thin, edge-on disk with a diameter of similar to 1.5 mas (0.6 pc). Fitting a three-dimensional warped disk model to the data, we measure a black hole mass of 2.42(-0.20)(+0.22) x 10(7) M-circle dot and a geometric distance to the system of 87.6(-7.2)(+7.9) Mpc. Assuming a cosmic microwave background-frame recession velocity of 7308.+/-.150 km s(-1), we constrain the Hubble constant to H-0 81.0(-6.9)(+7.4) (stat.).+/-.1.4 (sys.) km s(-1) Mpc(-1).