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A VLBI survey of weak extragalactic radio sources to align the ICRF and the future Gaia celestial reference frame

hal.structure.identifierLaboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
hal.structure.identifierObservatoire aquitain des sciences de l'univers [OASU]
hal.structure.identifierLaboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
dc.contributor.authorBOURDA, G.
hal.structure.identifierLaboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux [L3AB]
hal.structure.identifierObservatoire aquitain des sciences de l'univers [OASU]
hal.structure.identifierLaboratoire d'Astrophysique de Bordeaux [Pessac] [LAB]
dc.contributor.authorCHARLOT, P.
dc.contributor.authorPORCAS, R.
dc.contributor.authorGARRINGTON, S.
dc.date.issued2008
dc.date.conference2008-09-23
dc.description.abstractEnThe space astrometry mission Gaia will construct a dense optical QSO-based celestial reference frame. For consistency between optical and radio positions, it will be important to align the Gaia reference frame and the International Celestial Reference Frame (ICRF) with the highest accuracy. Currently, it is found that only 10% of the ICRF sources are suitable to establish this link (70 sources), either because they are not bright enough at optical wavelengths or because they have significant extended radio emission which precludes reaching the highest astrometric accuracy. In order to improve the situation, we have initiated a multi-step VLBI survey dedicated to finding additional suitable radio sources for aligning the two frames. The sample consists of about 450 sources, typically 20 times weaker than the current ICRF sources, which have been selected by cross-correlating optical and radio catalogues. This paper presents the observing strategy to detect, image, and measure accurate positions for these sources. It also provides results about their VLBI detectability, as derived from observations with the European VLBI Network in June and October 2007. Based on these observations, an excellent detection rate of 89% is found, which is very promising for the continuation of this project.
dc.language.isoen
dc.source.titleProc. 9th European VLBI Network Symposium
dc.title.enA VLBI survey of weak extragalactic radio sources to align the ICRF and the future Gaia celestial reference frame
dc.typeCommunication dans un congrès
dc.subject.halPlanète et Univers [physics]/Astrophysique [astro-ph]
dc.subject.halPhysique [physics]/Astrophysique [astro-ph]/Cosmologie et astrophysique extra-galactique [astro-ph.CO]
bordeaux.pagesous presse
bordeaux.countryIT
bordeaux.title.proceedingProc. 9th European VLBI Network Symposium
bordeaux.conference.cityBologne
bordeaux.peerReviewedoui
hal.identifierhal-00400993
hal.version1
hal.invitednon
hal.proceedingsoui
hal.conference.end2008-09-26
hal.popularnon
hal.audienceInternationale
hal.origin.linkhttps://hal.archives-ouvertes.fr//hal-00400993v1
bordeaux.COinSctx_ver=Z39.88-2004&rft_val_fmt=info:ofi/fmt:kev:mtx:journal&rft.btitle=Proc.%209th%20European%20VLBI%20Network%20Symposium&rft.date=2008&rft.spage=sous%20presse&rft.epage=sous%20presse&rft.au=BOURDA,%20G.&CHARLOT,%20P.&PORCAS,%20R.&GARRINGTON,%20S.&rft.genre=unknown


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