Winds from the Inner Region of Accretion Disks
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Steady disk winds, or jets, from the inner region of a geometrically thin accretion disk were studied under the assumption that the wind flow is confined within a hollow cylindrical-shell region. By using the cold-wind approximation, in which the variation of the flow properties perpendicular to the streamline is neglected, we integrated the physical quantities over the direction perpendicular to the wind flow. Then, the configuration of streamlines as well as the density and velocity profiles along the streamline were solved simultaneously. We have found that a wind is able to flow vertically. That is, as the cross-sectional area of the wind flow increases along with an increase in the distance from the disk, both the velocity and density decrease, and, accordingly, the Mach number increases with distance. At a sufficiently large height,z » r_c0＞ 5r_g ,where the wind reaches its terminal speed (0.2-0.5 times the initial velocity, depending on the parameters), the cross-sectional area varies as A chi z^(3/2), the density as rho chi z^(-3/2), the sound velocity as C_s chi z^(-l/2), and the Mach number M(=v/c_s ) as chi z^(l/2). Such a disk wind from the inner accretion disk accounts for the energetic jets from a transient X-ray source and the transient appearance of pair annihilation lines in X-ray Nova Muscae 1991.
- Publications of the Astronomical Society of Japan
Publications of the Astronomical Society of Japan 47(3), 317-321, 1995-06-25
Astronomical Society of Japan