HI Spectroscopy of Reverberation-Mapped Active Galactic Nuclei
  We present HI 21 cm spectroscopy from the GBT for the host galaxies of 31
nearby AGNs with direct M$_{\textrm{BH}}$ measurements from reverberation
mapping. These are the first published HI detections for 12 galaxies, and the
spectral quality is generally an improvement over archival data for the
remainder of the sample. We present measurements of emission-line fluxes,
velocity widths, and recessional velocities from which we derive HI mass, total
gas mass, and redshifts. Combining M$_{\textrm{GAS}}$ with constraints on
M$_{\textrm{STARS}}$ allows exploration of the baryonic content of these
galaxies. We find a typical M$_{\textrm{GAS}}$/M$_{\textrm{STARS}}$ fraction of
10%, with a few reaching $\sim$30-50%. We also examined several relationships
between M$_{\textrm{STARS}}$, M$_{\textrm{GAS}}$, M$_{\textrm{BH}}$, baryonic
mass, and morphological type. We find a weak preference for galaxies with
larger M$_{\textrm{GAS}}$ to host more massive black holes. We also find
gas-to-stellar fractions to weakly correlate with later types in unbarred
spirals, with an approximately constant fraction for barred spirals. Consistent
with previous studies, we find declining
M$_{\textrm{GAS}}$/M$_{\textrm{STARS}}$ with increasing M$_{\textrm{STARS}}$,
with a slope suggesting the gas reservoirs have been replenished. Finally, we
find a clear relationship for M$_{\textrm{BH}}$-M$_{\textrm{BARY}}$ with a
similar slope as M$_{\textrm{BH}}$-M$_{\textrm{STARS}}$ reported by Bentz &
Manne-Nicholas (2018). The dwarf Seyfert NGC 4395 appears to follow this
relationship as well, even though it has a significantly higher gas fraction
and smaller M$_{\textrm{BH}}$ than the remainder of our sample.
