Deep Astrometric Standards

I. Platais (1) , S. G. Djorgovski , C. Ducourant (2, 3, 4) , A. L. Fey (5) , S. Frey (6) , Z. Ivezic , K. J. Mighell , A. Rest , R. F. G. Wyse , N. Zacharias

1 Yale University Observatory
2 LAB - Laboratoire d'Astrophysique de Bordeaux [Pessac]
3 L3AB - Laboratoire d'astrodynamique, d'astrophysique et d'aéronomie de bordeaux
4 OASU - Observatoire aquitain des sciences de l'univers
5 US NAVAL OBSERVATORY - US Naval Observatory
6 MPE - Max-Planck-Institut für Extraterrestrische Physik

The advent of next generation imaging telescopes such as LSST and Pan-STARRS - instruments with wide fields and huge Giga-pixel cameras - will soon create a critical need for deep and precise reference frames for astrometric calibrations. The Deep Astrometric Standards (DAS) program aims to establish such a frame by providing astrometry at the 5-10 mas accuracy level in four 10 sq. deg Galactic fields, to a depth of V=25. We use 3-4 m class optical telescopes to set up these standards. The principal source of our reference frame is UCAC2 and VLBI positions of radio-loud QSOs having optical counterparts with V<25. The novelty of the DAS project is a new way of linking our observations to the ICRF. We pre-select the candidate radio-optical link sources from existing radio surveys, then conduct the VLA observations to measure the spectra and spatial compactness and, finally, observe the best 10-15 sources with the VLBI. So far, two out of the four DAS fields are in the advanced stages of construction.

Domaines: Cosmologie et astrophysique extra-galactique [astro-ph.CO]; Astrophysique [astro-ph]

I. Platais, S. G. Djorgovski, C. Ducourant, A. L. Fey, S. Frey, et al.. Deep Astrometric Standards. Nomenclature, Precession and New Models in Fundamental Astronomy, Aug 2006, Prague, Czech Republic. pp.38. ⟨hal-00130064⟩