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Accepted for publication in PASP Deep Astrometric Standards (DAS) and Galactic Structure (2005)
BibTeX
@MISC{Platais05acceptedfor,
author = {Imants Platais and Rosemary F. G. Wyse and Norbert Zacharias},
title = {Accepted for publication in PASP Deep Astrometric Standards (DAS) and Galactic Structure},
year = {2005}
}
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Abstract
The advent of next-generation imaging telescopes such as LSST and Pan-STARRS has revitalized the need for deep and precise reference frames. The proposed weak-lensing observations with these facilities put the highest demands on image quality over wide angles on the sky. It is particularly difficult to achieve a sub-arcsecond PSF on stacked images, where precise astrometry plays a key role. Current astrometric standards are insufficient to achieve the science goals of these facilities. We thus propose the establishing of a few selected deep (V =25) astrometric standards (DAS). These will enable a reliable geometric calibration of solid-state mosaic detectors in the focal plane of large ground-based telescopes and make a substantial contribution to our understanding of stellar populations in the Milky Way. In this paper we motivate the need for such standards and discuss the strategy of their selection and acquisition and reduction techniques. The feasibility of DAS is demonstrated by a pilot study around the open cluster NGC 188, using the KPNO 4m CCD Mosaic camera, and by Subaru Suprime-Cam observations. The goal of reaching an accuracy of 5-10 mas in positions and obtaining absolute proper motions good to 2 mas yr −1 over a several squaredegree area is challenging, but reachable with the NOAO 4m telescopes and CCD mosaic imagers or a similar set-up. Our proposed DAS aims to establish four fields near the Galactic plane, at widely separated coordinates. In addition – 2 – to their utilitarian purpose for DAS, the data we will obtain in these fields will enable fundamental Galactic science in their own right. The positions, proper motions, and V I photometry of faint stars will address outstanding questions of Galactic disk formation and evolution, stellar buildup and mass assembly via merger events.
Keyphrases
pasp deep astrometric standard galactic structure stellar population outstanding question several squaredegree area 5-10 ma sub-arcsecond psf utilitarian purpose mass assembly galactic plane galactic disk formation precise reference frame current astrometric standard pilot study large ground-based telescope milky way science goal stacked image faint star fundamental galactic science key role precise astrometry image quality focal plane open cluster ngc stellar buildup astrometric standard subaru suprime-cam observation solid-state mosaic detector weak-lensing observation reliable geometric calibration ccd mosaic camera absolute proper motion merger event substantial contribution reduction technique proper motion wide angle similar set-up
