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Multi-Frequency VLBI Observations of the GPS Source 1934–638

Published online by Cambridge University Press:  12 April 2016

A. K. Tzioumis ,
E. A. King ,
J. E. Reynolds ,
D. L. Jauncey ,
R. G. Gough ,
R. A. Preston ,
D. W. Murphy ,
S. J. Tingay ,
D. L. Meier  and
D. L. Jones
...Show all authors
A. K. Tzioumis
Affiliation:
Australia Telescope National Facility, Australia
E. A. King
Affiliation:
Australia Telescope National Facility, Australia
J. E. Reynolds
Affiliation:
Australia Telescope National Facility, Australia
D. L. Jauncey
Affiliation:
Australia Telescope National Facility, Australia
R. G. Gough
Affiliation:
Australia Telescope National Facility, Australia
R. A. Preston
Affiliation:
Jet Propulsion Laboratory, Pasadena, CA, USA
D. W. Murphy
Affiliation:
Jet Propulsion Laboratory, Pasadena, CA, USA
S. J. Tingay
Affiliation:
Jet Propulsion Laboratory, Pasadena, CA, USA
D. L. Meier
Affiliation:
Jet Propulsion Laboratory, Pasadena, CA, USA
D. L. Jones
Affiliation:
Jet Propulsion Laboratory, Pasadena, CA, USA
J. E.J. Lovell
Affiliation:
Institute of Space and Astronautical Science, Japan
P. G. Edwards
Affiliation:
Institute of Space and Astronautical Science, Japan
P. M. McCulloch
Affiliation:
University of Tasmania, Hobart, Australia
M. E. Costa
Affiliation:
University of Tasmania, Hobart, Australia
L. Kedziora-Chudczer
Affiliation:
University of Sydney, Sydney, Australia
D. Campbell-Wilson
Affiliation:
University of Sydney, Sydney, Australia
G. D. Nicolson
Affiliation:
Hartebeesthoek Radio Astronomy Observatory, Krugersdorp, South Africa
J. F. H. Quick
Affiliation:
Hartebeesthoek Radio Astronomy Observatory, Krugersdorp, South Africa

Abstract

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PKS 1934–638 is an archetypal GPS source, peaking at 1.4 GHz and exhibits almost no flux density variability. VLBI images at frequencies of .843, 2.3, 4.8, & 8.4 were made with the southern hemisphere VLBI array and they reveal that the source is a 42 mas compact double. There is no detectable change in separation over the last 20 years, yielding an upper limit of ~ 0.03c ± 0.2c on any expansion velocity. The spectral shapes of the two components are remarkably similar, despite indications of finer structure on longer baselines. Magnetic field calculations indicate fields of a few mGauss and the results are consistent with equipartition.

Type
Research Article
Information
International Astronomical Union Colloquium , Volume 164: Radio Emission from Galactic and Extragalactic Compact Sources , 1998 , pp. 179 - 180
Copyright
Copyright © Astronomical Society of the Pacific 1998

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