Insu Yi

ADVECTION-DOMINATED ACCRETION : A SELF-SIMILAR SOLUTION

We consider viscous rotating accretion flows in which most of the viscously dissipated energy is stored as entropy rather than being radiated. Such advection-dominated flows may occur when the optical depth is either very small or very large. We obtain a family of self-similar solutions where the temperature of the accreting gas is nearly virial and the flow is quasi-spherical. The gas rotates at much less than the Keplerian angular velocity; therefore, the central stars in such flows will cease to spin up long before they reach the break-up limit. Further, the Bernoulli parameter is positive, implying that advection-dominated flows are susceptible to producing outflows. Convection is likely in many of these flows and, if present, will tend to enhance the above effects. We suggest that advection-dominated accretion may provide an explanation for the slow spin rates of accreting stars and the widespread occurrence of outflows and jets in accreting systems.

Advection-dominated Accretion: Underfed Black Holes and Neutron Stars

We describe new optically thin solutions for rotating accretion flows around black holes and neutron stars. These solutions are advection dominated, so that most of the viscously dissipated energy is advected radially with the flow. We model the accreting gas as a two temperature plasma and include cooling by bremsstrahlung, synchrotron, and Comptonization. We obtain electron temperatures

A New Model for Black Hole Soft X-Ray Transients in Quiescence

T_esim 10^{8.5}-10^{10}

Is the Accretion Flow in NGC 4258 Advection Dominated

K. The new solutions are present only for mass accretion rates

Unified description of accretion flows around black holes

dot M

Relativistic Precessing Jets and Cosmological Gamma-Ray Bursts

less than a critical rate

Radio/X-Ray Luminosity Relation for Advection-dominated Accretion: Implications for Emission-Line Galaxies and the X-Ray Background

dot M_{crit}

On Fueling Gamma-Ray Bursts and Their Afterglows with Pulsars

which we calculate as a function of radius

Cosmological evolution of quasars

R

An Explanation for the Bimodal Duration Distribution of Gamma-Ray Bursts: Millisecond Pulsars from Accretion-induced Collapse

and viscosity parameter