Black hole masses of tidal disruption event host galaxies II
  We present new medium resolution, optical long-slit spectra of a sample of 6
UV/optical and 15 X-ray selected tidal disruption event candidate host
galaxies. We measure emission line ratios from the optical spectra, finding
that the large majority of hosts are quiescent galaxies, while those displaying
emission lines are generally consistent with star-formation dominated
environments; only 3 sources show clear evidence of nuclear activity. We
measure bulge velocity dispersions using absorption lines and infer host black
hole (BH) masses using the M-$\sigma$ relation. While the optical and X-ray
host BH masses are statistically consistent with coming from the same parent
distribution, the optical host distribution has a visible peak near $M_{\rm BH}
\sim 10^6 M_\odot$, whereas the X-ray host distribution appears flat in $M_{\rm
BH}$. We find a subset of X-ray selected candidates that are hosted in galaxies
significantly less luminous (M$_{\rm g}$$\sim$-16) and less massive (stellar
mass$\sim$10$^{8.5-9}$M$_{\odot}$) than those of optical events. Using
statistical tests we find suggestive evidence that, in terms of black hole
mass, stellar mass and absolute magnitude, the hard X-ray hosts differ from the
UV/optical and soft X-ray samples. Similar to individual studies, we find that
the emission region size for the X-ray sample is much smaller than the optical
emission region, consistent with a compact accretion disk. We find a typical
Eddington ratio of the X-ray emission is $\sim$0.01, as opposed to the optical
events which have L$_{\rm BB}$$\sim$L$_{\rm Edd}$.
