Discovery of Candidate X-ray Jets in High-Redshift Quasars

Bradford Snios, Daniel A. Schwartz, Aneta Siemiginowska, Małgosia Sobolewska, Mark Birkinshaw, C. C. Cheung, Doug B. Gobeille, Herman L. Marshall, Giulia Migliori, John F. C. Wardle, Diana M. Worrall

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


We present Chandra X-ray observations of 14 radio-loud quasars at redshifts $3 < z < 4$, selected from a well-defined sample. All quasars are detected in the 0.5-7.0 keV energy band, and resolved X-ray features are detected in five of the objects at distances of 1-12" from the quasar core. The X-ray features are spatially coincident with known radio features for four of the five quasars. This indicates that these systems contain X-ray jets. X-ray fluxes and luminosities are measured, and jet-to-core X-ray flux ratios are estimated. The flux ratios are consistent with those observed for nearby jet systems, suggesting that the observed X-ray emission mechanism is independent of redshift. For quasars with undetected jets, an upper limit on the average X-ray jet intensity is estimated using a stacked image analysis. Emission spectra of the quasar cores are extracted and modeled to obtain best-fit photon indices, and an Fe K emission line is detected from one quasar in our sample. We compare X-ray spectral properties with optical and radio emission in the context of both our sample and other quasar surveys.
Original languageEnglish
Article number130
JournalAstrophysical Journal
Issue number2
Publication statusPublished - 24 Jun 2021

Bibliographical note

Accepted to ApJ, 15 pages, 7 figures, 7 tables


  • active galactic nuclei
  • X-ray active galactic nuclei
  • high-redshift galaxies
  • jets
  • high energy astrophysics


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