Knottiness of X-ray jets: testing the obstacle-in-jet model (Speaker: Sarka Wykes, Harvard)

Monday, January 29, 12:00pm
Marlar Lounge 37-252

Recently, it has become evident that X-ray jets are ubiquitous in low-power radio galaxies. In addition to diffuse X-ray emission, many of the jets feature compact X-ray brightness enhancements ('knots'). Their radio morphology is often similar, but not identical, to the X-ray morphology, and in some cases optical counterparts are observed as well. The issue of the knot origin(s) is yet undecided, although models exist suggesting that the knots with non-zero proper motion represent moving plasma packets while the knots without detected proper motions would originate from obstacles in the jet (stars and/or clouds) in interaction with the jet plasma flow. I will show some results from our 2D hydrodynamical simulations and analytical calculations of Centaurus A's jet interacting with winds of its internal, evolved stars, with a view to investigating the properties of shocks generated in these interactions and their match to the observed X-ray knots. The fate of the material released by the embedded stars, which is carried away by the jet at a rate of ~ 0.002 solar masses per year, will be also briefly addressed.