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 GBT
and the VLA, 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 ~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 HSA to make a high-sensitivity VLBI 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 ~1.5 mas (0.6 pc). Fitting a three-dimensional warped disk model to
the data, we measure a black hole mass of $2.42^{+0.22}_{-0.20} \times 10^7$
M$_{\odot}$ and a geometric distance to the system of $87.6^{+7.9}_{-7.2}$ Mpc.
Assuming a CMB-frame recession velocity of $7308 \pm 150$ km s$^{-1}$, we
constrain the Hubble constant to $H_0 = 81.0^{+7.4}_{-6.9}$ (stat.) $\pm 1.4$
(sys.) km s$^{-1}$ Mpc$^{-1}$.
