We present new dynamical models of the S0 galaxy N3115 , making use of the available published photometry and kinematics as well as of two-dimensional TIGER spectrography .

The models are based on a detailed model of the luminosity distribution built using an MGE fit on HST/WFPC2 and ground-based photometric data .
We first examined the kinematics in the central 40 \arcsec in the light of two-integral f ( E,J ) models .
Jeans equations were used to constrain the mass to light ratio , and the central dark mass whose existence was suggested by previous studies .
The even part of the distribution function was then retrieved via the Hunter & Qian formalism .
We thus confirmed that the velocity and dispersion profiles in the central region could be well fit with a two-integral model , given the presence of a central dark mass of \sim 10 ^ { 9 } \mbox { M } _ { \sun } .
However , no two-integral model could fit the h _ { 3 } profile around a radius of about 25 \arcsec where the outer disc dominates the surface brightness distribution .

Three integral analytical models were therefore built using a Quadratic Programming technique .
These models showed that three integral components do indeed provide a reasonable fit to the kinematics , including the higher Gauss-Hermite moments .
Again , models without a central dark mass failed to reproduce the observed kinematics in the central arcseconds .
This clearly supports the presence of a nuclear black hole of at least 6.5 \times 10 ^ { 8 } \mbox { M } _ { \sun } in the centre of NGC 3115 .
These models were finally used to estimate the importance of the dark matter in the outer part of NGC 3115 , suggested by the flat stellar rotation curve observed by Capaccioli et al .
( 1993 ) .

This study finally points out the difficulty of integrating independently published data in a coherent and consistent way , thus demonstrating the importance of taking into account the details of the instrumental setup and the reduction processes .