Abstract
Part I: Relativistic jets emitted from the centers of some galaxies (called active galaxies) exhibit many interesting behaviors that are not yet fully understood: acceleration and collimation over vast distances, for instance, and occasional flaring activity. In the first part of my thesis, I examine the possibility of collimation and acceleration of relativistic jets by the pressure of the ambient medium surrounding the jet base. I discuss the differences in predicted jet behavior due to including the effects of a magnetic field threading the jet interior, and I describe the conditions that create some observed jet shapes, such as the “hollow cone” structure seen in M87 and similar jets. I also discuss what happens when the pressure outside of the jet drops so slowly that the jet shocks repeatedly, generating entropy at its boundary. Finally, I examine the spectra of the 40 brightest gamma-ray flares from blazars (active galaxies with jets pointed toward us) recorded by the Fermi Gamma-ray Space Telescope in its first four years of operation. I develop models to describe the observed behavior of these flares and discuss the physical implications of these models. Part II: The ability to clearly communicate scientific concepts to both peers and the lay public is an important component of being a scientist. Few training programs exist, however, for scien- tists to obtain these skills. In the second part of my thesis, I examine the impact of two different training efforts for very early-career scientists: first, a short science communication workshop for science, technology, engineering and math (STEM) graduate students, and second, science com- munication training integrated into existing astrophysics classes for undergraduate STEM majors and early STEM graduate students. I evaluate whether the students’ written communication skills demonstrate measurable improvement after training, and track students’ attitudes toward science communication.
