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Multi-Frequency Studies of Intrinsic Intraday Variability

Published online by Cambridge University Press:  12 April 2016

Stefan J. Wagner
Stefan J. Wagner*
Affiliation:
LSW Heidelberg, Germany

Abstract

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Intraday variability is detected in Blazars throughout the electromagnetic spectrum. Only radio emission is affected by interstellar scintillation. The characteristics of variability observed at different frequencies are often similar and suggest that intrinsic variations also contribute to the changes detected in the radio wavelength regime. This in turn implies very high brightness temperatures.

Unambiguous signatures of scintillation and of intrinsic changes have been identified. The properties of intrinsic variations are reviewed to illustrate their potential contribution to variability in the radio domain. Such intrinsic changes need to be discriminated against when studying scintillation in quasars and BL Lac objects. Observations of scintillating sources and of sources with significant intrinsic IDV suggest interesting modifications to the standard paradigm of AGN.

Type
Chapter Three Intra-Day Variability, Gravitational Lensing and Polarization
Information
International Astronomical Union Colloquium , Volume 182: Sources and Scintillations: Refraction and Scattering in Radio Astronomy , 2001 , pp. 105 - 111
Copyright
Copyright © Kluwer 2001

References

Begelman, M., Rees, M. and Sikora, M.: 1994, Astrophys. J. Lett. 429, 57–60.Google Scholar
de Bruyn, A.G.: 1988, Proceedings of IAU Symp. 129, 97–98.Google Scholar
Dennet-Thorpe, J. and de Bruyn, A.G.: 2000, Astrophys. J. Lett. 529, 65–68.Google Scholar
Hartman, R.C., Colimar, W., von Montigny, C. and Dermer, C.D.: 1997, Proceedings Fourth Compton Symposium, AIP 410 (1), 307–328.Google Scholar
Harvey, G.A., et al.: 1972, Astrophys. Lett. 11, 147–492.Google Scholar
Heidt, J. and Wagner, S.J.: 1996, Astron. Astrophys. 305, 42–52.Google Scholar
Heidt, J. and Wagner, S.J.: 1998, Astron. Astrophys. 329, 853–862.Google Scholar
Heeschen, D., Krichbaum, T., Schalinski, C. and Witzel, A.: 1987, Astron. J. 94, 1493–5072.Google Scholar
Junor, W., Biretta, J.A. and Livio, M.: 1999, Nature 401, 891–892.CrossRefGoogle Scholar
Kedziora-Chudczer, L., Jauncey, D.L., et al.: 1997, Astrophys. J. Lett. 490, 9–12.CrossRefGoogle Scholar
Mannheim, K.: 1998, Science 279, 684–686.Google Scholar
Marscher, A., Marchenko-Jorstad, S., Mattox, J., Wehrle, A. and Aller, M.: 2000, Proceedings: Astrophysical Phenomena Revealed by Space VLBI, ISAS, 39–46.Google Scholar
Maxscher, A.P.: 1992, Proceedings: Physics of Active Galactic Nuclei, Springer p. 510.Google Scholar
Mattox, J.R., Wagner, S.J., Malkan, M., et al.: 1997, Astrophys. J. 476, 692–712.Google Scholar
Oke, J.B.: 1967, Astrophys. J. 147, 901–907.CrossRefGoogle Scholar
Peng, B., Krans, A., Krichbaum, T.P., Müller, S., et al.: 2000, Astron. Astrophys. 353, 937–943.Google Scholar
Qian, S.-J., Quirrenbach, A., Witzel, A., et al: 1991, Astron. Astrophys. 241, 15–21.Google Scholar
Quirrenbach, A., Witzel, A., Wagner, S.J., et al.: 1991, Astrophys. J. 372, L71–L74.Google Scholar
Readhead, A.: 1994, Astrophys. J. 426, 51–59.CrossRefGoogle Scholar
Spada, M., Salvati, M. and Pacini, F.: 1999, Astrophys. J. 511, 136–141.Google Scholar
Wagner, S.J.: 1992, Proceedings: Gravitational Lenses, Springer, 189–195.Google Scholar
Wagner, S.J. and Witzel, A.: 1995, Annu. Rev. Astron. Astrophys. 33, 163–197.CrossRefGoogle Scholar
Wagner, S.J., Witzel, A., Kriehbaum, T.P., et al: Astron. Astrophys. 271, 344–352.Google Scholar
Wagner, S.J., Witzel, A., Heidt, J., et al: Astron. J. 1ll, 2187–2212.Google Scholar
Witzel, A., Heeschen, D., Schalinski, C., et al: 1986, Mitt. Astron. Ges. 65, 239–241.Google Scholar