Marshall, H LGelbord, J MWorrall, Diana MBirkinshaw, MarkSchwartz, D AJauncey, DavidGriffiths, GMurphy, D WLovell, JPerlman, EGodfrey, Leith2021-10-192021-10-190004-637Xhttp://hdl.handle.net/1885/251014We present Chandra X-ray imaging of a flux-limited sample of flat spectrum radio-emitting quasars with jet-like structure. X-rays are detected from 59% of 56 jets. No counter-jets were detected. The core spectra are fitted by power-law spectra with a photon index Γx, whose distribution is consistent with a normal distribution, with a mean of 1.61+0.04 -0.05 and dispersion of 0.15+0.04 -0.03. We show that the distribution of α rx, the spectral index between the X-ray and radio band jet fluxes, fits a Gaussian with a mean of 0.974 ±0.012 and dispersion of 0.077 ±0.008. We test the model in which kiloparsec-scale X-rays result from inverse Compton scattering of cosmic microwave background photons off the jet's relativistic electrons (the IC-CMB model). In the IC-CMB model, a quantity Q computed from observed fluxes and the apparent size of the emission region depends on redshift as (1 + z)3+α. We fit Q ∝ (1 + z)a, finding a = 0.88 ±0.90, and reject at 99.5% confidence the hypothesis that the average α rx depends on redshift in the manner expected in the IC-CMB model. This conclusion is mitigated by a lack of detailed knowledge of the emission region geometry, which requires deeper or higher resolution X-ray observations. Furthermore, if the IC-CMB model is valid for X-ray emission from kiloparsec-scale jets, then the jets must decelerate on average: bulk Lorentz factors should drop from about 15 to 2-3 between parsec and kiloparsec scales. Our results compound the problems that the IC-CMB model has in explaining the X-ray emission of kiloparsec-scale jets.Support for this work was provided in part by the National Aeronautics and Space Administration (NASA) through the Smithsonian Astrophysical Observatory (SAO) contract SV3- 73016 to MIT for support of the Chandra X-Ray Center (CXC), which is operated by SAO for and on behalf of NASA under contract NAS8-03060. Support was also provided by NASA under contract NAS 8-39073 to SAO.application/pdfen-AU© 2018. The American Astronomical Society201810.3847/1538-4357/aaaf662020-11-23CC Attribution 3.0 License