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Clues to the X-ray emission mechanisms in flat radio spectrum AGNs

  • D. M. Worrall
V. X-ray Observation and Modeling
Part of the Lecture Notes in Physics book series (LNP, volume 307)

Abstract

Clues to the X-ray emission mechanisms in flat radio spectrum AGNs arise from comparing radio, optical, and X-ray luminosities for a sample of 80 known-redshift radio-selected AGNs for which the radio luminosity is dominated by flat-spectrum compact-core emission. The X-ray spectral luminosity lies on average above an extrapolation from lower frequencies for all the QSOs, despite a range in optical polarization and activity. Such an X-ray “excess” is often interpreted as support for the presence of a Compton-scattered component. In contrast, for the BL Lac objects, the X-ray spectral luminosity on average lies on the extrapolation from lower frequencies. This is particularly interesting in view of evidence that the X-ray emission of BL Lac objects may be unbeamed while the radio emission is beamed. If the 80 sample sources are assumed to be preferentially beamed towards the observer in radio emission, because of their radio selection, a test supports the X-ray emission also being beamed. However, the BL Lac sub-sample is too small for the test to be applied to it alone.

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Copyright information

© Springer-Verlag 1988

Authors and Affiliations

  • D. M. Worrall
    • 1
  1. 1.Harvard-Smithsonian Center for AstrophysicsCambridgeUSA

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