X-ray emission properties of large scale jets, hotspots and lobes in active galactic nuclei

Jun Kataoka*, Lukasz Stawarz

*Corresponding author for this work

Research output: Chapter in Book/Report/Conference proceedingConference contribution


We examine a systematic comparison of jet-knots, hotspots and radio lobes recently observed with Chandra and ASCA. The data was compiled at radio (5 GHz) and X-ray frequencies (1keV) for more than 40 radio galaxies. We examined three models for the X-ray production: synchrotron (SYN), synchrotron self-Compton (SSC) and external Compton on CMB photons (EC). For the SYN sources, X-ray photons are produced by ultrarelativistic electrons with energies 10-100 TeV that must be accelerated in situ. For the other objects, a simple formulation of calculating the "expected" SSC or EC fluxes under an equipartition hypothesis is presented. We confirmed that the observed X-ray fluxes are close to the expected ones for non-relativistic emitting plasma velocities in the case of radio lobes and majority of hotspots, whereas considerable fraction of jet-knots is too bright at X-rays to be explained in this way. We concluded, if the inverse-Compton model is the case, the X-ray bright jet-knots are most likely far from the minimum-power condition. We however prefer the other possibility, namely that the observed X-ray emission from all of the jet-knots is synchrotron in origin.

Original languageEnglish
Title of host publicationX-ray Universe 2005
Number of pages2
Publication statusPublished - 2006 Apr 10
Externally publishedYes
EventX-ray Universe 2005 - Madrid, Spain
Duration: 2005 Sept 262005 Sept 30

Publication series

NameEuropean Space Agency, (Special Publication) ESA SP
ISSN (Print)0379-6566


ConferenceX-ray Universe 2005


  • Galaxies: jets
  • Magnetic fields
  • Radiation mechanism: non-thermal

ASJC Scopus subject areas

  • Aerospace Engineering
  • Space and Planetary Science


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