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Intraday Variability and Microarcsecond Structure in Blazar Cores

Published online by Cambridge University Press:  13 May 2016

David L. Jauncey ,
Lucyna Kedziora-Chudczer ,
J. E. J. Lovell ,
Jean-Pierre Macquart ,
George D. Nicolson ,
Rick A. Perley ,
John E. Reynolds ,
A.K. Tzioumis ,
Mark A. Wieringa  and
Hayley E. Bignall
David L. Jauncey
Affiliation:
Australia Telescope National Facility, CSIRO, Epping, NSW, Australia
Lucyna Kedziora-Chudczer
Affiliation:
Australia Telescope National Facility, CSIRO, Epping, NSW, Australia Anglo-Australian Observatory, Epping, NSW, Australia
J. E. J. Lovell
Affiliation:
Australia Telescope National Facility, CSIRO, Epping, NSW, Australia
Jean-Pierre Macquart
Affiliation:
RCfTA, School of Physics, University of Sydney, NSW, Australia
George D. Nicolson
Affiliation:
Hartebeesthoek Radio Astronomy Observatory, Krugersdorp, South Africa
Rick A. Perley
Affiliation:
National Radio Astronomy Observatory, Socorro, NM, USA
John E. Reynolds
Affiliation:
Australia Telescope National Facility, CSIRO, Epping, NSW, Australia
A.K. Tzioumis
Affiliation:
Australia Telescope National Facility, CSIRO, Epping, NSW, Australia
Mark A. Wieringa
Affiliation:
Australia Telescope National Facility, CSIRO, Epping, NSW, Australia
Hayley E. Bignall
Affiliation:
Department of Physics and Mathematical Physics, University of Adelaide, SA, Australia

Abstract

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The accumulation of evidence now strongly favours interstellar scintillation (ISS) as the principal mechanism causing intra-day variability (IDV) at cm wavelengths. While ISS reduces the implied brightness temperatures, they remain uncomfortably high. The distance to the scattering screen is an important parameter in determining the actual brightness temperature encountered. The high brightness temperatures, the presence of strong and variable circular polarization and the observed lifetimes of a decade or more for several IDV sources, pose significant problems for synchrotron theory.

“The fault, dear Brutus, is not in our stars, but in ourselves, that we are underlings.” William Shakespeare, Julius Caesar

Type
The Inner Regions of Galaxies
Information
Symposium - International Astronomical Union , Volume 205: Galaxies and their Constituents at the Highest Angular Resolutions , 2001 , pp. 84 - 87
Copyright
Copyright © Astronomical Society of the Pacific 2001 

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