An X-Ray imaging survey of Quasar jets: testing the inverse compton model
Marshall, HL and Gelbord, JM and Schwartz, DA and Murphy, DW and Lovell, JEJ and Worrall, DM and Birkinshaw, M and Perlman, ES and Godfrey, L and Jauncey, DL, An X-Ray imaging survey of Quasar jets: testing the inverse compton model, Astrophysical Journal Supplement Series, 193, (1) Article 15. ISSN 0067-0049 (2011) [Refereed Article]
We present results from continued Chandra X-ray imaging and spectroscopy of a flux-limited sample of flat spectrum
radio-emitting quasars with jet-like extended structure. X-rays are detected from 24 of the 39 jets observed so far.
We compute the distribution of αrx, the spectral index between the X-ray and radio bands, showing that it is broad,
extending at least from 0.8 to 1.2. While there is a general trend that the radio brightest jets are detected most
often, it is clear that predicting the X-ray flux from the radio knot flux densities is risky, so a shallow X-ray survey
is the most effective means for finding jets that are X-ray bright. We test the model in which the X-rays result
from inverse Compton (IC) scattering of cosmic microwave background (CMB) photons by relativistic electrons
in the jet moving with a high bulk Lorentz factor nearly along the line of sight. Depending on how the jet magnetic
fields vary with z, the observed X-ray to radio flux ratios do not follow the redshift dependence expected from the
IC–CMB model. For a subset of our sample with known superluminal motion based on VLBI observations, we
estimate the angle of the kiloparsec-scale jet to the line of sight by considering the additional information in the
bends observed between parsec- and kiloparsec-scale jets. These angles are sometimes much smaller than estimates
based on the IC–CMB model with a Lorentz factor of 15, indicating that these jets may decelerate significantly
from parsec scales to kiloparsec scales.