We analyze the nuclear stellar dynamics of the SB0 galaxy NGC 1023 , utilizing observational data both from the Space Telescope Imaging Spectrograph aboard the Hubble Space Telescope and from the ground .
The stellar kinematics measured from these long-slit spectra show rapid rotation ( V \approx 70 km s ^ { -1 } at a distance of 0 \farcs 1 = 4.9 pc from the nucleus ) and increasing velocity dispersion toward the nucleus ( where \sigma = 295 \pm 30 km s ^ { -1 } ) .
We model the observed stellar kinematics assuming an axisymmetric mass distribution with both two and three integrals of motion .
Both modeling techniques point to the presence of a central dark compact mass ( which presumably is a supermassive black hole ) with confidence > 99 % .
The isotropic two-integral models yield a best-fitting black hole mass of ( 6.0 \pm 1.4 ) \times 10 ^ { 7 } M _ { \odot } and mass-to-light ratio ( M / L _ { V } ) of 5.38 \pm 0.08 , and the goodness-of-fit ( \chi ^ { 2 } ) is insensitive to reasonable values for the galaxy ’ s inclination .
The three-integral models , which non-parametrically fit the observed line-of-sight velocity distribution as a function of position in the galaxy , suggest a black hole mass of ( 3.9 \pm 0.4 ) \times 10 ^ { 7 } M _ { \odot } and M / L _ { V } of 5.56 \pm 0.02 ( internal errors ) , and the edge-on models are vastly superior fits over models at other inclinations .
The internal dynamics in NGC 1023 as suggested by our best-fit three-integral model shows that the velocity distribution function at the nucleus is tangentially anisotropic , suggesting the presence of a nuclear stellar disk .
The nuclear line of sight velocity distribution has enhanced wings at velocities \geq 600 km s ^ { -1 } from systemic , suggesting that perhaps we have detected a group of stars very close to the central dark mass .