Mass Accretion Rate of Rotating Viscous Accretion Flow
  The mass accretion rate of transonic spherical accretion flow onto compact
objects such as black holes is known as the Bondi accretion rate(Mdot_B), which
is determined only by the density and the temperature of gas at the outer
boundary. But most work on disc accretion has taken the mass flux to be a given
with the relation between that parameter and external conditions left
uncertain. Within the framework of a slim alpha disk, we have constructed
global solutions of the rotating, viscous hot accretion flow and determined its
mass accretion rate as a function of density, temperature, and angular momentum
of gas at the outer boundary. We find that the low angular momentum flow
resembles the spherical Bondi flow and its mass accretion rate approaches the
Bondi accretion rate for the same density and temperature at the outer
boundary. The high angular momentum flow on the other hand is the conventional
hot accretion disk with advection, but its mass accretion rate can be
significantly smaller than the Bondi accretion rate with the same boundary
conditions. We also find that when the temperature at the outer boundary is
equal to the virial temperature, solutions exist only for 0.05 ~< mdot ~< 1
when alpha=0.01 where mdot==Mdot/Mdot_B. We also find that the dimensionless
mass accretion rate is roughly independent of the radius of the outer boundary
but inversely proportional to the angular momentum at the outer boundary and
proportional to the viscosity parameter, mdot ~= 9.0 alpha/lambda when 0.1 ~<
mdot ~< 1, where the dimensionless angular momentum measure lambda == l_out/l_B
is the specific angular momentum of gas at the outer boundary l_out in units of
l_B == GM/c_{s,out}, and $c_{s,out}$ the isothermal sound speed at the outer
boundary.
