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Interstellar scintillation, AGN physics and the SKA

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Open access
Authors
Bignall, Hayley
Lovell, J
Rickett, B.J.
Macquart, Jean-Pierre
Jauncey, J.
Kedziora-Chudczer, L.
Ojha, Roopesh
Pursimo, T.
Senkbeil, C.
Shabala, S.
Dutka, M.
Date
2008
Type
Conference Paper

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Citation
Bignall, Hayley and Lovell, J. and Rickett, B.J. and Macquart, Jean-Pierre and Jauncey, J. and Kedziora-Chudczer, L. and Ojha, Roopesh and Pursimo, T. and Senkbeil, C. and Shabala, S. and Dutka, M. 2008. Interstellar scintillation, AGN physics and the SKA, in 18th National AIP Physics Congress, Australian Institute of Physics Conference Proceedings, Nov 30 2008, Adelaide, South Australia: Australian Institute of Physics AIP.
Source Title
Australian Institute of Physics Conference Proceedings
Source Conference
18th National AIP Physics Congress
ISBN
Faculty
Department of Medical Imaging and Applied Physics
School of Science
Faculty of Science and Engineering
Remarks

This Australian Institute of Physiscs conference paper may be available at: http://www.aip.org.au/conferences.php

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Abstract

A large fraction of compact, extragalactic radio sources exhibit rapid variability at centimetre wavelengths as their radio emission is scattered by electron density fluctuations in the interstellar medium of the Galaxy. Next-generation wide-field radio telescopes will have to account for this in forming deep images of the radio sky. Interstellar scintillation offers a unique probe of very small-scale structure in both the ionized interstellar medium and the compact jets of the radio sources themselves. The effective resolution is two orders of magnitude higher than achievable with very long baseline interferometry. The recent Micro-Arcsecond Scintillation-Induced Variability Survey revealed a reduction in ISS at 4.9 GHz with increasing source redshift, implying either an increase in the apparent angular size of high-redshift radio cores beyond that expected due to a cosmological decrease in brightness, or a decrease in the microarcsecond-scale core dominance towards high redshift. The result could be due either to source-intrinsic evolution in the selected sample, or to scatter-broadening in the intergalactic medium.