X-ray observations of jets

The current status of X-ray emission from jets, as observed by the Einstein X-ray Observatory, is reviewed. The X-rays were detected from the jets of 3C273, M87, and Centaurus A. Preliminary results from VLA observations of the Centaurus A jet are also discussed. In all three cases, the data indicate synchrotron radiation, with the spectral index breaking in the range of 10 to the 14th power to 10 to the 15th power Hz; in situ acceleration of the relativistic electrons is required, since the electron lifetimes are significantly shorter than the light travel times from the nucleus. Thermal confinement of the jets is possible in some but not all regions.