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A. S. Wilson, A. J. Young (UMd), P. L. Shopbell (Caltech)
We present the results of observations of Pictor A and Cygnus A (the most luminous radio galaxies in the local universe) with Chandra. The Pictor A observations reveal a 2 arc min (110 kpc) long X-ray emitting jet. The previously known X-ray emitting hot spot (associated with the radio hot spot at the putative jet terminus some 240 kpc from the nucleus) has also been imaged and found to have a morphology very similar to that found in the radio and optical. The X-ray emission of the hot spot is not a simple spectral continuation of the synchrotron emission at radio and optical wavelengths. Thermal models for the hot spot X-ray emission are ruled out by the Chandra spectrum and the required gas density, while synchrotron self-Compton models require extremely low magnetic field strengths. We favor a synchrotron model for the X-rays, but from a separate population to that which emits the radio and optical emission. The results thus imply the presence of \gamma ~ 107-8 relativistic electrons and have significant implications for the origin of high energy cosmic rays (present authors, ApJ, submitted).
In Cygnus A, we find a) synchrotron self-Compton emission from the radio hot spots, b) a heavily cut-off, but spatially extended, nuclear source with significant line emission, c) a large scale, ``football-shaped'' cavity in the intracluster gas, apparently inflated by the relativistic plasma generated by the radio jets, d) evidence for X-ray emission from the jets and e) large-scale thermal X-ray emission from the intracluster gas. This research was supported by NASA through grant NAG 81027.