TheChandra X‐Ray ObservatoryResolves the X‐Ray Morphology and Spectra of a Jet in PKS 0637−752

The core-dominated radio-loud quasar PKS 0637-752 (z = 0.654) was the firstcelestial object observed with the Chandra X-ray Observatory, offering theearly surprise of the detection of a remarkable X-ray jet. Several observationswith a variety of detector configurations contribute to a total exposure timewith the Chandra Advanced CCD Imaging Spectrometer (ACIS; Garmire et al. 2000,in preparation) of about 100ks. A spatial analysis of all the available X-raydata, making use of Chandra's spatial resolving power of about 0.4 arcsec,reveals a jet that extends about 10 arcsec to the west of the nucleus. At leastfour X-ray knots are resolved along the jet, which contains about 5% of theoverall X-ray luminosity of the source. Previous observations of PKS 0637-752in the radio band (Tingay et al. 1998) had identified a kpc-scale radio jetextending to the West of the quasar. The X-ray and radio jets are similar inshape, intensity distribution, and angular structure out to about 9 arcsec,after which the X-ray brightness decreases more rapidly and the radio jet turnsabruptly to the north. The X-ray luminosity of the total source is log Lx ~45.8 erg/s (2 - 10keV), and appears not to have changed since it was observedwith ASCA in November 1996. We present the results of fitting a variety ofemission models to the observed spectral distribution, comment on thenon-existence of emission lines recently reported in the ASCA observations ofPKS 0637-752, and briefly discuss plausible X-ray emission mechanisms.Comment: 24 pages, includes 8 figures, Accepted for publication in Ap