Unifying X-ray emission properties of large scale jets, hotspots and lobes in AGN

Jun Kataoka*, Łukasz Stawarz

*Corresponding author for this work

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

1 Citation (Scopus)


We examine a systematic comparison of jet-knots, hotspots and radio lobes recently observed with Chandra and ASCA. This report will discuss the origin of their X-ray emissions and investigate the dynamics of the jets. The data was compiled at well sampled 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 - mostly jet-knots in nearby low-luminosity radio galaxies - X-ray photons are produced by ultrarelativistic electrons with energies 10-100 TeV that must be accelerated in situ. For the other objects, conservatively classified as SSC or EC sources, a simple formulation of calculating the "expected" X-ray 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 examined two possibilities to account for the discrepancy in a framework of the inverse-Compton model: (1) magnetic field is much smaller than the equipartition value, and (2) the jets are highly relativistic on kpc/Mpc scales. We also briefly discuss 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 publicationHigh Energy Gamma-Ray Astronomy - 2nd International Symposium on High Energy Gamma-Ray Astronomy
Number of pages6
Publication statusPublished - 2005
Externally publishedYes
EventInternational Symposium on High Energy Gamma-Ray Astronomy - Heidelberg, Germany
Duration: 2004 Jul 262004 Jul 30

Publication series

NameAIP Conference Proceedings
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616


ConferenceInternational Symposium on High Energy Gamma-Ray Astronomy

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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