Résumé :
The origin of broad
emission lines in active galactic nuclei (AGNs) has remained a
mystery since they were first discovered over 60 years ago. They have
been variously explained in terms of radiatively driven outflows,
inflows, rotating accretion disks, and the atmospheres of stars
orbiting close to the AGN. A small number of AGNs have
kinematically determined central black hole masses. They also exhibit
broad emission lines. Since the gravitational field strength is known
in these nuclei, the relationship between velocity and radius may be
established, given a kinematic model for the gas, allowing the broad
emission lines to be modelled. The first results of this type of
analysis will be described for the nearby galaxy M81, which harbors a
low luminosity Seyfert nucleus.
