Jet stability and the generation of superluminal and stationary components
Abstract
We present numerical simulations of the jet stability after the ejection of superluminal components in relativistic jets. These simulations are obtained using a relativistic time-dependent 2D hydrodynamical code from which simulated radio maps are computed by integrating the transfer equations for synchrotron radiation. The interaction of the perturbation associated with the superluminal component with the underlying jet results in the formation of multiple conical shocks behind the rarefaction that follows the main shock. These trailing components can be easily distinguished because they appear to be released from the primary superluminal component, instead of being ejected from the core. Their conical nature should also result in distinct polarization properties. Those appearing closer to the core show small apparent motions and a very slow secular decrease in brightness, from which could be associated with stationary components, while those appearing farther downstream should be weaker and can reach superluminal apparent motions. The existence of these trailing components indicates that not all observed components are necessarily identified with perturbations at the jet inlet; rather, multiple emission components can be generated by a single disturbance in the jet. The energy flow injected at the base of the jet therefore does not need to vary as might be inferred from changes in the positions and brightness of features seen downstream. The superluminal components associated with jet inlet perturbations exhibit a very stable pattern speed, however, trailing components have velocities that increase with distance from the core. This latter effect represents a true acceleration of the assumed relativistically hot jet fluid; if observed, such accelerations would favor an electro-positron composition in the jet.
- Publication:
-
Young European Radio Astronomers' Conference (YERAC)
- Pub Date:
- 2000
- Bibcode:
- 2000yera.confE...1A