Contribution
Dissipation in the jet of Centaurus A
Presenter: Paul Nulsen (Harvard-Smithsonian Center for Astrophysics)
Abstract: The eastern jet of Centaurus A is well resolved in Chandra X-ray images, which have been used to measure its bounding pressure and width. Combining the results with estimates of jet power and initial speed permit the construction of a 1-dimensional model for flow through the jet. The flow is inconsistent with Bernoulli's theorem, implying that there is substantial internal dissipation. The most likely cause is mass entrainment by the jet. Since the flow is over-constrained, the rate of entrainment can be determined and it is found to be consistent with the rate of stellar mass loss within the body of the jet. Some implications will be discussed. If dissipation is dominated by stellar mass injection, jet width becomes highly sensitive to the bounding pressure, so that small changes in the environment can determine whether the jet remains confined or expands rapidly in width, so inflating a radio lobe. The may account for the asymmetry in the radio morphology of Centaurus A.