Estimation of the mass outflow rates from viscous accretion discs

Abstract

We study the viscous accretion disc around black holes, and all possible accretion solutions, including shocked as well as shock-free accretion branches. Shock-driven bipolar outflows from a viscous accretion disc around a black hole have been investigated. One can identify two critical viscosity parameters, αcl and αcu, within which the stationary shocks may occur, for each set of boundary conditions. Adiabatic shock has been found for up to viscosity parameter α = 0.3, while in the presence of dissipation and mass loss we have found stationary shock up to α = 0.15. The mass outflow rate may increase or decrease with the change in disc parameters, and is usually around a few to 10 per cent of the mass inflow rate. We show that for the same outer boundary condition, the shock front decreases to a smaller distance with the increase in α. We also show that the increase in dissipation reduces the thermal driving in the post-shock disc, and hence the mass outflow rate decreases up to a fewper cent.