IngentaConnect Radio Intra-Day Variability: Answers and Questions

Authors: Jauncey D.L.¹; Kedziora-Chudczer L.²; Lovell J.E.J.³; Macquart J-P.⁴; Nicolson G.D.⁵; Perley R.A.⁶; Reynolds J.E.⁷; Tzioumis A.K.⁸; Wieringa M.H.⁹; Bignall H.E.¹⁰

Source: Astrophysics and Space Science, Volume 278, Numbers 1-2, 2001 , pp. 87-92(6)

Publisher: Springer

Abstract:

Intra-day variability (IDV) of active galactic nuclei (AGN) has been detected from gamma-ray energies to radio wavelengths. At high energies, such variability appears to be intrinsic to the sources themselves. However, at radio wavelengths, brightness temperatures as high as 10^18 to 10^21 K are encountered if the IDV is intrinsic to the source. We discuss here the accumulating evidence showing that, at radio wavelengths where the highest brightness temperatures are encountered, interstellar scintillation (ISS) is the principal mechanism causing IDV. While ISS reduces the implied brightness temperatures, they still remain uncomfortably high.

Language: English

Document Type: Regular paper

Affiliations: 1: Australia Telescope National Facility, CSIRO, Australia E-mail: djauncey@atnf.csiro.au 10: Department of Physics and Mathematical Physics, University of Adelaide, SA, Australia E-mail: hbignall@physics.adelaide.edu.au 2: Australia Telescope National Facility, and Anglo-Australian Observatory, Epping NSW, Australia; E-mail: lkedzior@atnf.csiro.au 3: Australia Telescope National Facility, CSIRO, Australia; E-mail: jlovell@atnf.csiro.au 4: RCfTA, School of Physics, University of Sydney, NSW, Australia; E-mail: jpm@physics.usyd.edu.au 5: Hartebeesthoek Radio Astronomy Observatory, Krugersdorp, South Africa E-mail: george@hartrao.ac.za 6: National Radio Astronomy Observatory, Socorro, NM, U.S.A.; E-mail: rperley@nrao.edu 7: Australia Telescope National Facility, CSIRO, Australia; E-mail: jreynold@atnf.csiro.au 8: Australia Telescope National Facility, CSIRO, Australia; E-mail: atzioumi@atnf.csiro.au 9: Australia Telescope National Facility, CSIRO, Australia; E-mail: mwiering@atnf.csiro.au

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