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Radio Intra-Day Variability: Answers and Questions

  • David L. Jauncey
  • Lucyna Kedziora-Chudczer
  • James E. J. Lovell
  • Jean-Pierre Macquart
  • George D. Nicolson
  • Rick A. Perley
  • John E. Reynolds
  • Anastasios K. Tzioumis
  • Mark H. Wieringa
  • Hayley E. Bignall
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  • 109 Downloads

Abstract

Intra-day variability (IDV) of active galactic nuclei (AGN) has been detected from gamma-rayenergies to radio wavelengths. At high energies, such variability appears to be intrinsic to thesources themselves. However, at radio wavelengths, brightness temperatures as high as 1018 to1021 K are encountered if the mv is intrinsic to the source. We discuss here the accumulating evidenceshowing that, at radio wavelengths where the highest brightness temperatures are encountered,interstellar scintillation (ISS) is the principal mechanism causing IDV. While ISS reduces the impliedbrightness temperatures, they still remain uncomfortably high.

Keywords

Brightness Temperature Active Galactic Nucleus VLBI Observation Radio Wavelength Astrophysical Phenomenon 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer Science+Business Media Dordrecht 2001

Authors and Affiliations

  • David L. Jauncey
    • 1
  • Lucyna Kedziora-Chudczer
    • 2
  • James E. J. Lovell
    • 1
  • Jean-Pierre Macquart
    • 3
  • George D. Nicolson
    • 4
  • Rick A. Perley
    • 5
  • John E. Reynolds
    • 1
  • Anastasios K. Tzioumis
    • 1
  • Mark H. Wieringa
    • 1
  • Hayley E. Bignall
    • 6
  1. 1.Australia Telescope National FacilityCSIROAustralia
  2. 2.Australia Telescope National Facility, and Anglo-Australian ObservatoryEppingAustralia
  3. 3.RCfTA, School of PhysicsUniversity of SydneyAustralia
  4. 4.Hartebeesthoek Radio Astronomy ObservatoryKrugersdorpSouth Africa
  5. 5.National Radio Astronomy ObservatorySocorroUSA
  6. 6.Department of Physics and Mathematical PhysicsUniversity of AdelaideAustralia

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