Kiloparsec-scale jets in FR I radio galaxies and the γ-ray background

Stawarz*, T. M. Kneiske, J. Kataoka

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

34 Citations (Scopus)


We discuss the contribution of kiloparsec-scale jets in FR I radio galaxies to the difiuse γ-ray background radiation. The analyzed γ-ray emission comes from inverse-Compton scattering of starlight photon fields by the ultrarelativistic electrons whose synchrotron radiation is detected from such sources at radio, optical, and X-ray energies. We find that these objects, under the minimum-power hypothesis (corresponding to a magnetic field of 300 μG in the brightest knots of these jets), can contribute about one percent to the extragalactic γ-ray background measured by EGRET. We point out that this result already indicates that the magnetic fields in kiloparsec-scale jets of low-power radio galaxies are not likely to be smaller than 10 μG on average, as otherwise the extragalactic γ-ray background would be overproduced.

Original languageEnglish
Pages (from-to)693-698
Number of pages6
JournalAstrophysical Journal
Issue number2 I
Publication statusPublished - 2006 Feb 1
Externally publishedYes


  • Galaxies: active
  • Galaxies: jets
  • Gamma rays: theory
  • Radiation mechanisms: nonthermal

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


Dive into the research topics of 'Kiloparsec-scale jets in FR I radio galaxies and the γ-ray background'. Together they form a unique fingerprint.

Cite this