Dr Ken Kellerman (National Radio Astronomy Observatory USA)

Relativistic Jets in Blazars and AGN: Status and Problems - Dr Ken Kellerman Colloquium

ATNF Marsfield Lecture Theatre

Abstract

Relativistic jets transport energy from the central engine of radio galaxies and quasars to distant radio lobes. I will describe the results of an ongoing VLBA program to study the structure, polarization, and time evolution of milliarcsecond scale radio jets and the implications for relativistic beaming models. From the observed motions, brightness temperatures, and luminosities we have estimated the distribution of intrinsic Lorentz factors, intrinsic luminosities, and the balance between relativistic particle energy and magnetic energy in the jets. It appears that in each jet, there is a well defined bulk flow velocity which differs from source to source with most jets being only mildly relativistic. Most jets are very straight, but some show curved or even helical trajectories. Due to Doppler boosting, the apparent brightness temperature can greatly exceed the inverse Compton limit. In their quiescent state, the magnetic and particle energy in jet cores appear to be in balance, but following the ejection or acceleration of new particles, the particle energy greatly exceeds the magnetic energy.