Pulsars, transients and relativistic astrophysics

Abstract:

A list is presented of known extragalactic radio jets which also have associated X-ray emission. The canonical emission processes for the production of X-rays are reviewed and the sources axe categorized on the basis of our current understanding. Although it seems clear that the X-ray emission is non-thermal, the two possible processes, synchrotron and inverse Compton emission, arise from extremely high energy (synchrotron) or extremely low energy (beaming models with IC emission), relativistic electrons. Only synchrotron self-Compton emission from a few hot-spots provides information on the 'normal' energy range of the electrons responsible for the observed radio emission.

Abstract:

We apply a model for an adiabatically expanding relativistic jet to the radio galaxy B2 0755+379 using the observed surface brightness and jet width obtained from VLA and MERLIN radio images. We derive velocity profiles along the main jet for various assumed starting conditions, and show that these profiles axe consistent with the observed jet/counter-jet brightness ratio provided that the angle to the line of sight of the jet is theta similar or equal to 27degrees and the starting velocity of the jet (actually. the velocity at 0.5 kpc from the nucleus) is similar or equal to 0.9c.

Abstract:

Non-relativistic and relativistic models in which astrophysical jets are deflected on passing through an isothermal high density region are analysed. The criteria for the stability of jets to be affected by the formation of internal shocks are discussed.