2005MNRAS.356..145C

Centrifugal pressure of matter spiralling on to black holes has long been known to produce standing or oscillating shocks. The post-shock disc puffs up in the form of a torus, which intercepts soft photons from the outer Keplerian disc and inverse-Comptonizes them to produce hard photons. The post-shock region also produces jets. We study the interaction of both hard photons and soft photons, with rotating electron-positron jets. We show that hard photons from the post-shock torus are instrumental in acceleration of jets, while soft photons from the Keplerian disc is a better collimating agent. We also show that if the jets are launched closer to the black hole, relativistic and collimated jets are produced; if they are launched at larger distances both collimation and acceleration are less. We also show that if the shock location is at relatively larger distances from the black hole, collimation is better.