We present results from a kinematical study of the gas in the nucleus of a
sample of three LINER galaxies, obtained from archival HST/STIS long-slit
spectra. We found that, while for the elliptical galaxy NGC 5077, the observed
velocity curves are consistent with gas in regular rotation around the galaxy's
center, this is not the case for the two remaining objects. By modeling the
surface brightness distribution and rotation curve from the emission lines in
NGC 5077, we found that the observed kinematics of the circumnuclear gas can be
accurately reproduced by adding to the stellar mass component a black hole mass
of M_bh = 6.8 (-2.8,+4.3) 10**8 M_sun (uncertainties at a 1 sigma level); the
radius of its sphere of influence (R_sph ~ 0".34) is well-resolved at the HST
resolution. The BH mass estimate in NGC 5077 is in fairly good agreement with
both the M_bh-M_bul (with an upward scatter of ~ 0.4 dex) and M_bh-sigma
correlations (with an upward scatter of 0.5 dex in the Tremaine et al. form and
essentially no scatter using the Ferrarese et al. form) and provides further
support for the presence of a connection between the ``residuals'' from the
M_bh-sigma correlation and the bulge effective radius. This indicates the
presence of a black hole's ``fundamental plane'' in the sense that a
combination of at least sigma and R_e drives the correlations between M_bh and
host bulge properties.Comment: Accepted for publication in A&