Published in:

Astrophysical Journal 730,2 (2011)


The Chandra X-ray Observatory has proven to be a vital tool for studying high-energy emission processes in jets associated with active galactic nuclei (AGNs). We have compiled a sample of 27 AGNs selected from the radio flux-limited MOJAVE (Monitoring of Jets in AGNs with VLBA Experiments) sample of highly relativistically beamed jets to look for correlations between X-ray and radio emission on kiloparsec (kpc) scales. The sample consists of all MOJAVE quasars that have over 100 mJy of extended radio emission at 1.4 GHz and a radio structure of at least 3 '' in size. Previous Chandra observations have revealed X-ray jets in 11 of 14 members of the sample, and we have carried out new observations of the remaining 13 sources. Of the latter, 10 have X-ray jets, bringing the overall detection rate to similar to 78%. Our selection criterion, which is based on highly compact, relativistically beamed jet emission and large extended radio flux, thus provides an effective method of discovering new X-ray jets associated with AGNs. The detected X-ray jet morphologies are generally well correlated with the radio emission, except for those displaying sharp bends in the radio band. The X-ray emission mechanism for these powerful FR II (Fanaroff-Riley type II) jets can be interpreted as inverse Compton scattering off of cosmic microwave background photons by the electrons in the relativistic jets. We derive viewing angles for the jets, assuming a non-bending, non-decelerating model, by using superluminal parsec scale speeds along with parameters derived from the inverse Compton X-ray model. We use these angles to calculate best-fit Doppler and bulk Lorentz factors for the jets, as well as their possible ranges, which leads to extreme values for the bulk Lorentz factor in some cases. When both the non-bending and non-decelerating assumptions are relaxed the only constraints on the kpc-scale jet from the Chandra and Very Large Array observations are an upper limit on the viewing angle, and a lower limit on the bulk Lorentz factor.

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