Relativistic jet ejections from slim disks

Abstract

An ejection mechanism of relativistic jets from slim disks is studied. Since the radiation pressure is dominant in the slim disk, radiative energy flow arises along the pressure gradient in the vertical direction. The divergence of the radiative flux tells us that the radiative energy flow from a bottom layer near the equatorial plane is absorbed by another layer upper than the boundary surface. The absorbed energy accumulates in the upper layer as the matter advances inward and calculations show that the specific energy of the flow in the upper layer can be as large as $\sim c^{2}$ near the black hole when the accretion rate through the upper layer is relatively low. Since the specific energy $\sim c^{2}$ is much larger than the gravitational energy, the height of the upper layer could significantly increase then. Hence, the innermost part of the upper layer after almost all the angular momentum has been removed could have a much larger height than the black hole size and collide with one another around the central axis of the disk, bouncing back from the axis as simultaneously expanding along the axis. The flow is expected to go outward along the central axis and to become supersonic due to the cross-section-change of the flow, getting the relativistic jets finally.