MUNA Lunch Talk:

Dan Homan

Department of Physics & Astronomy, Denison University

Accelerated Motions in AGN Jets

December 6

12:10PM, Room 230, NRAO, Edgemont Road


The process of collimation and acceleration of powerful extra-galactic radio jets is still not fully understood. A key aspect of this problem has been a lack of systematic studies of jet acceleration based on direct measurement of the apparent motion of jet features. I discuss the results of a recent study we've published of acceleration measurements for the motions of 203 specific jet features in 64 different jets from the MOJAVE VLBA program. We find that "parallel" accelerations, representing changes in apparent speed, are generally larger than "perpendicular" accelerations that represent changes in direction, indicating that a significant fraction of the observed changes in jet feature motion are due to intrinsic changes in speed rather than changes in direction to the line of sight. We also find that jet features with decreasing speed tend to be further from the base of their jets than components with increasing speed. This suggests a link between the observed jet feature motion and the jet flow which, in some cases, may increase near the base of the jet and decrease further out. In addition to these results, I will discuss some extensions to this work that are currently in progress.