2000A&A...360...99R

ROSAT HRI observations of 3C 273 reveal X-ray emission all along the optically visible jet with the peak of emission at the inner end. Whereas the X-ray emission from the innermost knotA is consistent with a continuation of the radio-to-optical synchrotron continuum, a second population of particles with higher maximum energy has to be invoked to explain the X-ray emission from knots B, C and D in terms of synchrotron radiation. Inverse Compton emission could account for the X-ray flux from the hot spot. We detect a faint X-ray halo with a characteristic scale of 29kpc and particle density on the order of 6x10⁴m^–3, higher than previously thought.