X-ray and gamma-ray spectroscopy and polarization of active galaxies and their jets:  constraints on emission mechanisms and jet content

Grzegorz Madejski

About 1 in 10 active galaxies posesses a relativistic jet.  Whenever the measurements of polarization  are possible (i.e. in the radio, IR and optical bands), the radiation arising from those jets is polarized, implying synchrotron radiation as the emission mechanism in those bands.  In this talk, I will discuss implications of recent spectral studies of blazars revealing constraints on the composition of their jets.  While there were no current X-ray or gamma-ray polarimetric observations of such jets, it is possible to discuss prospects and implications of such future polarimetric measurements on possible emission mechanisms:  I will cover those briefly.