Prague Relativistic Astrophysics

Silke Britzen

Very Long Baseline Interferometry (VLBI) observations provide the highest resolution information in Astronomy. They allow us to study the jets and the immediate vicinities of the active supermassive black holes in galaxies. In my talk, I will present our most recent results on two prototypical active black holes. OJ287 is the best candidate galaxy for hosting a supermassive binary black hole at very close separation. To our knowledge, this is the first time we can explain the historic light-curve variability and long-term jet kinematics in geometrical terms - by jet precession and jet rotation. The jet might be launched from the ergosphere of the active black hole. For the nearby, giant radio galaxy M87 with a supermassive black hole of 10^9 solar masses, we find strong indication for turbulent processes connecting the accretion disk and the jet. For both active galaxies we can provide insights into the long-standing problem of the origin of astrophysical jets.