A correlation between the stellar and [Fe II] velocity dispersions in
  Active Galaxies
  We use near-infrared spectroscopic data from the inner few hundred parsecs of
a sample of 47 active galaxies to investigate possible correlations between the
stellar velocity dispersion (sigma_star), obtained from the fit of the K-band
CO stellar absorption bands, and the gas velocity dispersion (sigma) obtained
from the fit of the emission-line profiles of [SIII]0.953um, [Fe II]1.257um,
[FeII]1.644um and H_2 2.122um. While no correlations with sigma_star were found
for H_2 and [SIII], a good correlation was found for the two [Fe II] emission
lines, expressed by the linear fit sigma_star = 95.4\pm16.1 +
(0.25\pm0.08)sigma_[Fe II]. Excluding barred objects from the sample a better
correlation is found between sigma_star and sigma_[FeII], with a correlation
coefficient of R=0.80 and fitted by the following relation: sigma_\star =
57.9\pm23.5 + (0.42\pm0.10)sigma_[FeII]. This correlation can be used to
estimate $\sigma_\star$ in cases it cannot be directly measured and the [FeII]
emission lines are present in the spectra, allowing to obtain the mass of the
supermassive black hole (SMBH) from the M-\sigma_\star relation. The scatter
from a one-to-one relationship between sigma_star and its value derived from
sigma_[FeII] using the equation above for our sample is 0.07dex, which is
smaller than that obtained in previous studies which use \sigma_[OIII] in the
optical as a proxy for sigma_star. The use of sigma_[Fe\,II] in the near-IR
instead of sigma_[OIII] in the optical is a valuable option for cases in which
optical spectra are not available or are obscured, as is the case of many AGN.
