Impressed by a widespread misunderstanding of the issue, we return to the old question concerning
the location of the inner edge of the accretion disk around a black hole. That is, \the inner edge
does not coincide with the location of the inner most ...
Impressed by a widespread misunderstanding of the issue, we return to the old question concerning
the location of the inner edge of the accretion disk around a black hole. That is, \the inner edge
does not coincide with the location of the inner most stable Keplerian circular orbit." We show
that the
ow does not have a potential minimum for accretion rates _
> 10LE=c2, with LE
being the Eddington luminosity and c being the speed of light. This property is realized even for
relatively small viscosity parameters (i.e., 0:01) because of the eect of the pressure gradient.
In conclusion, an argument based on the last circular orbit of a test particle cannot give a correct
inner boundary for the super-critical
ow, and the inner edge should be determined in connection
with radiation eciency.