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Radio Spectral Variability of the Nearby GPS Galaxy PKS 1718–649

Published online by Cambridge University Press:  05 March 2013

S. J. Tingay  and
M. de Kool
S. J. Tingay
Affiliation:
Centre for Austrophysics and Supercomputing, Swinburne University of Technology, P.O. Box 218, Hawthorn, VIC 3122, Australia. [email protected]
M. de Kool
Affiliation:
Research School of Astronomy and Astrophysics, Australian National University, Cotter Road, Weston, ACT 2611, Australia.
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Abstract

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Data from new Australia Telescope Compact Array observations of a nearby gigahertz peaked spectrum radio source, PKS 1718–649, show significant variability both below and above the spectral turnover frequency during a nine month period. Simple models of synchrotron self-absorption (SSA) and free–free absorption (FFA) cannot explain the individual spectra or the spectral variability. Novel SSA or FFA models will need to be investigated in order to explain the complex variability in this source. Some potential explanations for the spectral variability are explored here but we can make no strong conclusion about which of SSA or FFA (or alternative mechanisms) causes the peaked spectrum in PKS 1718–649.

Keywords

galaxies: activegalaxies: individual (PKS 1718–649)radio continuum: galaxiestechniques: interferometric
Type
GPS/CSS Workshop
Information
Publications of the Astronomical Society of Australia , Volume 20 , Issue 1 , 2003 , pp. 140 - 143
Copyright
Copyright © Astronomical Society of Australia 2003

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