The Structure of the M87 Jet: A Transition from Parabolic to Conical Streamlines
Distribution of the radius of the M87 jet as a function of the deprojected distance from the core in units of r_s (Schwarzschild radius).
The jet is described by two different shapes. The solid line indicates a parabolic structure with a power-law index a of 1.7, while the dashed line indicates a conical structure with a of 1.0. HST-1 is located around 5 × 10^5 r_s. The black area shows the size of the minor axis of the event horizon of the spinning black hole with maximum spin. The gray area indicates the size of the major axis of the event horizon of the spinning black hole with maximum spin, and corresponds to the size of the event horizon of the Schwarzschild black hole. The dotted line indicates the size of the inner stable circular orbit (ISCO) of the accretion disk for the Schwarzschild black hole. (Asada, K. & Nakamura, M., 2012, ApJL, 745, L28)