Multifrequency Circular Polarization Spectra as Probes of AGN Jet Physics

Regents Of The University Of Michigan - Ann Arbor, Ann Arbor MI

Investigators

Abstract

AST-0607523 Aller Some of the fundamental properties of the jets in Active Galactic Nuclei (AGN), and of their physical connection to the massive black holes and accretion disks which power and launch them, remain enigmatic. This project involves the study of the small component of circularly polarized radio frequency emission, which can provide important clues concerning the topology and role of the magnetic fields in AGN evolution, and the nature of the relativistic particles, in the emitting regions. This work uses extensive multi-frequency polarimetry at the University of Michigan 26-meter paraboloid, combined with selected observations at other facilities, to study the time variability of polarized radiation and compare it with radiative transfer models. These comparisons will determine the amount of order in the magnetic fields and the true identity of the emitting particles, which is central to understanding the environments of massive black holes and the mechanisms by which energy is extracted from them. The large and expanding database of unique measurements of active objects during outburst will continue to be made readily available to other researchers for independent scientific studies. Undergraduate and graduate students, including some from other institutions, gain important experience by working directly with data, and the Michigan radio telescope continues to provide critical training for future astronomers.