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Black Holes and Cosmic Jets
I study distant active galaxies. Active galaxies are extremely energetic galaxies, giving off so much energy that they can be viewed from billions of light years away. All of the unusual, energetic behavior in an active galaxy can ultimately be traced to its galactic center or nucleus, a region only a few light years across. These objects are therefore often called "Active Galactic Nuclei" or "AGN" for short. It is now believed that all AGN have, at their center, a super-massive black hole that is millions or even billions of times the mass of our Sun. Matter falling inward toward the black hole dramatically releases energy to generate the phenomena we observe.
There is a sub-class of AGN that have strong jets of plasma which stream outward from the galactic nucleus and are visible at radio wavelengths. These radio jets come in a number of morphologies with the most spectacular maintaining collimated flows for tens or even hundreds of thousands of light-years before terminating at hotspots in large, inflated radio lobes. I study these jets to understand their physical properties and how they are created by the super-massive black hole and accretion disk of in-falling matter at the center of the galaxy.