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Global astrometric sphere reconstruction in Gaia: challenges and first results of the Verification Unit

Published online by Cambridge University Press:  06 January 2010

Alberto Vecchiato ,
Ummi Abbas ,
Beatrice Bucciarelli ,
Mario G. Lattanzi  and
Roberto Morbidelli
Alberto Vecchiato
Affiliation:
Osservatorio Astronomico di Torino, via Osservatorio 20, 10025 Pino Torinese (TO), Italy email: vecchiato@oato.inaf.it
Ummi Abbas
Affiliation:
Osservatorio Astronomico di Torino, via Osservatorio 20, 10025 Pino Torinese (TO), Italy email: vecchiato@oato.inaf.it
Beatrice Bucciarelli
Affiliation:
Osservatorio Astronomico di Torino, via Osservatorio 20, 10025 Pino Torinese (TO), Italy email: vecchiato@oato.inaf.it
Mario G. Lattanzi
Affiliation:
Osservatorio Astronomico di Torino, via Osservatorio 20, 10025 Pino Torinese (TO), Italy email: vecchiato@oato.inaf.it
Roberto Morbidelli
Affiliation:
Osservatorio Astronomico di Torino, via Osservatorio 20, 10025 Pino Torinese (TO), Italy email: vecchiato@oato.inaf.it
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Abstract

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Gaia will estimate the astrometric and physical data of approximately one billion objects. The core of this process, the global sphere reconstruction, is represented by the reduction of a subset of these objects, which will constitute the largest and most precise catalog of absolute astrometry in the history of Astronomy, and will put General Relativity to test by estimating the PPN parameter γ with unprecedented accuracy. As the Hipparcos mission showed, and as it is natural for all kind of absolute measurements, possible errors in the data reduction can hardly be identified at the end of the processing, and can lead to systematic errors in all the works which will use these results. In order to avoid such kind of problems, a Verification Unit was established by the Gaia Data Processing and Analysis Consortium (DPAC). One of its jobs is to implement and perform an independent global sphere reconstruction, parallel to the baseline one, to compare the two results, and to report any significant difference.

Keywords

Astrometrycatalogsrelativity
Type
Contributed Papers
Information
Proceedings of the International Astronomical Union , Volume 5 , Symposium S261: Relativity in Fundamental Astronomy: Dynamics, Reference Frames, and Data Analysis , April 2009 , pp. 337 - 341
Copyright
Copyright © International Astronomical Union 2010

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