论文标题
Megamaser宇宙学项目。 xi。几何距离CGCG 074-064
The Megamaser Cosmology Project. XI. A geometric distance to CGCG 074-064
论文作者
论文摘要
作为Megamaser宇宙学项目的调查组成部分的一部分，我们在Galaxy CGCG 074-064中发现了一个磁盘Megamaser系统。使用GBT和VLA，我们在两年的时间内每月获得了Maser系统的光谱监测观察结果。我们发现，系统性MASER功能显示〜4.4 km s $^{ - 1} $ yr $^{ - 1} $的视线加速度几乎与速度保持恒定，而高速度maser功能显示出与零一致的加速度。我们还使用HSA在CGCG 074-064中对MASER系统的高敏化VLBI图进行了高度敏感，这表明Masers位于直径约为1.5 mas（0.6 PC）的薄的边缘磁盘中。将三维翘曲的磁盘模型安装到数据中，我们的黑洞质量为$ 2.42^{+0.22} _ { - 0.20} \ times 10^7 $ m $ _ {\ odot} $，几何距离与$ 87.6^{+7.9}} {+7.9} _ {+7.9} _ _ { - 7.2} $的几何距离。假设CMB-Frame衰退速度为$ 7308 \ pm 150 $ km s $^{ - 1} $，我们将哈勃常数限制为$ h_0 = 81.0^{+7.4} _ { - 6.9} $（stat。
As part of the survey component of the Megamaser Cosmology Project, we have discovered a disk megamaser system in the galaxy CGCG 074-064. Using the GBT and the VLA, we have obtained spectral monitoring observations of this maser system at a monthly cadence over the course of two years. We find that the systemic maser features display line-of-sight accelerations of ~4.4 km s$^{-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$^{-1}$.
