Sites of Particle Acceleration in Quasar Jets

Alan MarscherBoston University

Research Web Page: www.bu.edu/blazars

Jets of Quasars

43 GHz

1 mas = 2.6 pc

Knots require particle acceleration

Spectral energy distribution (SED) reveals very high E component with nearly flat power-law electron energy distribution N(E) as well as another with steeper N(E)

Compact jet: SED of individual knots not defined over broad spectral range, could either be a power law or closer to monoenergetic; polarization generally oblique to jet axis

Emission Regions in an AGN

Issues:

Origin of bright knots: oblique shocks? Something else?

Core of jet seen on VLBI images: site of standing shock, reconnection, or end of flow acceleration?

Rampant particle acceleration many kpc downstream: shocks?

Unbeamed

Beamed

Sketch of Physical Structure of Jet, AGN