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Source structure: an essential piece of information for generating the next ICRF

Published online by Cambridge University Press:  01 October 2007

P. Charlot ,
A. L. Fey ,
A. Collioud ,
R. Ojha ,
D. A. Boboltz  and
J. I. B. Camargo
P. Charlot
Affiliation:
Laboratoire d'Astrophysique de Bordeaux, Université Bordeaux 1, CNRS BP 89, 33270 Floirac, France email: charlot@obs.u-bordeaux1.fr
A. L. Fey
Affiliation:
U.S. Naval Observatory3450 Massachusetts Ave., NW, Washington, DC 20392-5420, USA
A. Collioud
Affiliation:
Laboratoire d'Astrophysique de Bordeaux, Université Bordeaux 1, CNRS BP 89, 33270 Floirac, France email: charlot@obs.u-bordeaux1.fr
R. Ojha
Affiliation:
U.S. Naval Observatory3450 Massachusetts Ave., NW, Washington, DC 20392-5420, USA
D. A. Boboltz
Affiliation:
U.S. Naval Observatory3450 Massachusetts Ave., NW, Washington, DC 20392-5420, USA
J. I. B. Camargo
Affiliation:
Observatorio do Valongo, Universidade Federal do Rio de JaneiroLadeira do Pedro Antônio, 43, Rio de Janeiro, RJ, Brazil
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Abstract

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The intrinsic radio structure of the extragalactic sources is one of the limiting factors in defining the International Celestial Reference Frame (ICRF). This paper reports about the ongoing work to monitor the structural evolution of the ICRF sources by using the Very Long Baseline Array and other VLBI telescopes around the world. Based on more than 5000 VLBI images produced from such observations, we have assessed the astrometric suitability of 80% of the ICRF sources. The number of VLBI images for a given source varies from 1 for the least-observed sources to more than 20 for the intensively-observed sources. Overall, we identify a subset of 194 sources that are highly compact at any of the available epochs and which are prime candidates for the realization of the next ICRF with the highest accuracy.

Keywords

astrometryreference systemsquasars: general
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 3 , Symposium S248: A Giant Step: from Milli- to Micro-arcsecond Astrometry , October 2007 , pp. 344 - 347
Copyright
Copyright © International Astronomical Union 2008

References

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