The principal objective of our work at Trinity is to conduct a high-resolution radio study of active galactic nuclei (AGN) that will make major contributions to our understanding of the physics of relativistic jets in these objects and, in the process, shed light on unified models of active galaxies. Active galaxies, including quasars and radio galaxies, most likely harbor supermassive black holes in their central regions that are ultimately responsible for the intense, episodic emission the nuclei of these galaxies exhibit. By electromagnetic processes which are still not well understood, material is accelerated in the vicinity of the black hole and channeled into narrow channels, or jets, that travel outward near the speed of light.

Physical models of jets generally predict that their observed properties will strongly depend on the orientation of the jet axis to our line of sight from Earth. Thus to perform statistical tests of these models, extended radio sources covering a very wide range in orientation will be studied: a complete sample of twenty-five of the most powerful quasars, and a representative sample of about a dozen related radio galaxies. Radio telescopes working in unison as interferometers will be used to image the jets in these objects on scales from light-years up to millions of light-years; the images will be used to look for systematic trends in the jet structures as a function of orientation angle. Time sequences of jets on light-year scales will be used to determine the statistical distribution of apparent faster-than-light, or "superluminal", jet speeds and to follow the trajectories of the relativistic outflows. Observations that measure the spectra and polarization of the radio emission will be used to determine physical conditions in the jets and to map their magnetic fields, which are expected to show different patterns depending on jet orientation. In addition, the first systematic study of the time variability of the radio emission from the nuclei of extended radio sources will be performed.

Unified models attempt to explain various observed classes of active galaxies - quasars, radio galaxies, blazars, Seyfert galaxies, and others - in a common physical framework. Since relativistic jets are an integral part of this framework, the statistics of radio jet properties will have clear implications for these unified models. Additionally, there is some possibility that these statistics could lead to estimates of the size and age of the universe.

Undergraduates - from both Trinity University and the Alamo Community College District - will be highly impacted by direct participation in this research, which will enhance their preparation for graduate study and offer students from underrepresented groups the opportunity to do science as they consider career options in the physical sciences.