Teaching
My primary research interest is the study of relativistic jets. An astronomical jet is a
long, thin stream of material that emanates from the nucleus of the central object, and
deposits its material some distance from the origin. Jets are observed emanating from
many astronomical objects, ranging from newborn stars to super-massive black holes in
galactic nuclei. Jets associated with active galactic nuclei (AGN) are some of the
largest objects in the universe, reaching lengths of over a million light years, and
having bulk flow velocities near the speed of light.Computer simulations of relativistic jet hydrodynamics have been available for some years. However, these simulations have a basic limitation. The hydrodynamic simulations give us the distribution of energy, density and momentum in the simulated jet. Renderings of these distributions do not resemble the radio flux maps of real jets. This is because the flow is relativistic. The effects of beaming, time delay, and Doppler boost dominate the emission. These effects are strongly related to angle of view. A small change in angle of view can result in a very different radio flux distribution. In addition, the effects of time-delay are important, as the photon crossing time is longer than the evolutionary time-scale of the flow. In my work, I attempt relate the emission we observe to the physical conditions in the jet by an analysis of the radiation transfer calculation through simulated flows. By determining the physical conditions present when bright features form in the simulated jet we can begin to understand what conditions lead to the formation of bright features in real jets. I have developed a suite of computer programs that use the output of a hydrodynamic simulation to generate a time-delayed simulated flux map of the simulated jet, at any angle of view. This software can be used to generate maps of both two-dimensional and three dimensional simulations. After the maps have been made, we can examine the physical conditions that lead to the formation of bright features in the jet. This tool is a new way of analyzing the simulations. Below are links to 2D images, 3D images, as well as animations of evolutionary sequences of jet formation. |
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Link to 2D images
Link to 3D images Link to Movies |