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Monthly VLBI Monitoring of Selected Gamma-Bright Quasars

Published online by Cambridge University Press:  12 April 2016

S. Britzen*
Affiliation:
Max-Planck-Institut für Radioastronomie, Bonn, Germany
A. Witzel
Affiliation:
Max-Planck-Institut für Radioastronomie, Bonn, Germany
T.P. Krichbaum
Affiliation:
Max-Planck-Institut für Radioastronomie, Bonn, Germany
J. Roland
Affiliation:
CNRS, Inst. d’Astrophysique, Paris, France; Leiden observatory, Netherlands
S.J. Wagner
Affiliation:
Landessternwarte Heidelberg, Königstuhl, 69117 Heidelberg, Germany
*
1Present address: NFRA, 7991 PD Dwingeloo, Netherlands.

Abstract

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In the past few years EGRET observations of extragalactic radio sources demonstrated the presence of blazars at high energies and supplied informations about their enormous luminosities. Questions arose whether outbursts at these high frequencies can be linked to structural changes in the radio regime and the need for VLBI monitoring became obvious. In the past two decades geodetic VLBI measurements gathered this kind of data.

We analyzed λ =3.6 cm observations with high time-resolution (up to once a month) from the geodetic IRIS campaigns for the γ-ray active quasars PKS 0420-014 and PKS 0528+134. In both sources superluminally moving jet components could be traced over time periods of several years on curved trajectories. Both sources exhibit component ejections preceding the time of an observed gamma-ray flaring.

Type
Research Article
Copyright
Copyright © Astronomical Society of the Pacific 1998

References

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