Relativistic Flows at the Hotspots of Radio Galaxies and Quasars?

Abstract

We review the broad band properties of X-ray detected hotspots in radio galaxies and quasars. We show that their collective properties can be unified in a framework involving frequency dependent relativistic beaming and varying orientations to the observer's line of sight. The simplest dynamic model consistent with this picture is a slowing-down relativistic flow downstream from the hotspot shock, suggesting that the jet flow remains relativistic to the hotspot distances.

To be published in the proceedings of the Bologna conference ``The Physics of Relativistic Jets in the Chandra and XMM Era'', New Astronomy Review eds. G. Brunetti, D. E. Harris, R. M. Sambruna and G. Setti