A Multi-band Study of the remarkable Jet in Quasar 4C+19.44

D.E. Harris, N.P. Lee, D.A. Schwartz, A. Siemiginowska, F. Massaro, Mark Birkinshaw, Diana Worrall, C.C. Cheung, J.M. Gelbord, Svetlana G Jostad, Alan P Marscher, H. Landt, H. Marshall, E.S. Perlman, L. Stawarz, Y. Uchiyama, C.M. Urry

Research output: Contribution to journalArticle (Academic Journal)peer-review

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We present arc-second-resolution data in the radio, IR, optical and X-ray for 4C+19.44 (=PKS 1354+195), the longest and straightest quasar jet with deep X-ray observations. We report results from radio images with half to one arc-second angular resolution at three frequencies, plus HST and Spitzer data. The Chandra data allow us to measure the X-ray spectral index in 10 distinct regions along the 18 arcsec jet and compare with the radio index. The radio and X-ray spectral indices of the jet regions are consistent with a value of α=0.80 throughout the jet, to within 2 sigma uncertainties. The X-ray jet structure to the south extends beyond the prominent radio jet and connects to the southern radio lobe, and there is extended X-ray emission in the direction of the unseen counter jet and coincident with the northern radio lobe. This jet is remarkable since its straight appearance over a large distance allows the geometry factors to be taken as fixed along the jet. Using the model of inverse Compton scattering of the cosmic microwave background (iC/CMB) by relativistic electrons, we find that the magnetic field strengths and Doppler factors are relatively constant along the jet. If instead the X-rays are synchrotron emission, they must arise from a population of electrons distinct from the particles producing the radio synchrotron spectrum.
Original languageEnglish
Article number119
Number of pages18
JournalAstrophysical Journal
Issue number2
Early online date8 Sep 2017
Publication statusPublished - 10 Sep 2017


  • radiation mechanisms:
  • non-thermal — quasars
  • individual (4C+19.44) — galaxies
  • jets — galaxies
  • active


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