Radiatively Inefficient Accretion: Breezes, Winds and Hyperaccretion
  We reformulate the adiabatic inflow-outflow (ADIOS) model for radiatively
inefficient accretion flows, treating the inflow and outflow zones on an equal
footing. For purely adiabatic flows (i.e., with no radiative losses), we show
that the mass flux in each zone must satisfy Mdot ~ R^n with n=1, in contrast
to previous work in which 0<n< 1 is a free parameter but in rough agreement
with numerical simulations. We also demonstrate that the resulting two-zone
ADIOS models are not dynamically self-consistent without the introduction of an
energy source close in to the central regions of the flow; we identify this
with the energy liberated by accretion. We explore the parameter space of
non-radiative models and show that both powerful winds and gentle breezes are
possible. When small radiative losses (with fixed efficiency) are included, any
centrally injected energy flux is radiated away and the system reverts to a
power-law behavior with n < 1, where n falls in a small range determined by the
fractional level of radiative losses. We also present an ADIOS model for
hypercritical (super-Eddington) disk accretion, in which the radiative losses
are closely related to the flow geometry. We suggest that hyperaccretion can
lead to either winds or breezes.
