X-ray emission processes in radio jets

The emission processes responsible for the observed X-rays from radio jets are commonly believed to be nonthermal, but in any particular case, it is unclear if synchrotron emission or one or more varieties of inverse Compton emission predominates. We present a formulation of inverse Compton emission from a relativistically moving jet ("IC/beaming") that relies on radio-emitting synchrotron sources for which the energy densities in particles and fields are comparable. We include the nonisotropic nature of inverse Compton scattering of the relativistic electrons on photons of the cosmic microwave background (CMB) and provide beaming parameters for a number of jets. A list of X-ray-emitting jets is given and the jets are classified on the basis of their morphology and spectral energy distribution to determine their likely emission process. We conclude that these jets have significant bulk relativistic velocities on kiloparsec scales, that higher redshift sources require less beaming because the energy density of the CMB is significantly greater than locally, and that for some nearby sources synchrotron X-ray emission predominates because the jet makes a large angle to the line of sight.