Revised astrometric calibration of the Gemini Planet Imager

Creators: De Rosa, Robert J.; Wang, Jason J.; Bailey, Vanessa; Millar-Blanchaer, Maxwell A.; Wallace, J. Kent

Abstract

We present a revision to the astrometric calibration of the Gemini Planet Imager (GPI), an instrument designed to achieve the high contrast at small angular separations necessary to image substellar and planetary-mass companions around nearby, young stars. We identified several issues with the GPI data reduction pipeline (DRP) that significantly affected the determination of the angle of north in reduced GPI images. As well as introducing a small error in position angle measurements for targets observed at small zenith distances, this error led to a significant error in the previous astrometric calibration that has affected all subsequent astrometric measurements. We present a detailed description of these issues and how they were corrected. We reduced GPI observations of calibration binaries taken periodically since the instrument was commissioned in 2014 using an updated version of the DRP. These measurements were compared to observations obtained with the NIRC2 instrument on Keck II, an instrument with an excellent astrometric calibration, allowing us to derive an updated plate scale and north offset angle for GPI. This revised astrometric calibration should be used to calibrate all measurements obtained with GPI for the purposes of precision astrometry.

Additional Information

© 2020 The Authors. Published by SPIE under a Creative Commons Attribution 4.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. Paper 19112 received Oct. 18, 2019; accepted for publication Jan. 21, 2020; published online Feb. 13, 2020. The authors wish to thank Brian Chinn, Carlos Quiroz, Ignacio Arriagada, Thomas Hayward, and Carlos Alvarez for their useful discussions relating to this work. Supported by NSF under Grant Nos. AST-1411868 (R. D. R., E. L. N., K. B. F., B. M., and J. P.); AST-141378 (G. D.); AST-1518332 (R. D. R., J. J. W., T. M. E., J. R. G., and P. G. K.); and AST1411868 (J. H. and J. P.). Supported by NASA under Grant Nos. NNX14AJ80G (R. D. R., E. L. N., B. M., F. M., and M. P.); NSSC17K0535 (R. D. R, E. L. N., B. M., and J. B. R.); NNX15AC89G and NNX15AD95G (R. D. R., B. M., J. E. W., T. M. E., G. D., J. R. G., and P. G. K.). This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract No. DE-AC52-07NA27344. This work benefited from NASA's Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASA's Science Mission Directorate. J. R. was supported by the French National Research Agency in the framework of the Investissements d'Avenir Program (Grant No. ANR-15-IDEX-02). Based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), National Research Council (Canada), CONICYT (Chile), Ministerio de Ciencia, Tecnología e Innovación Productiva (Argentina), Ministério da Ciência, Tecnologia e Inovação (Brazil), and Korea Astronomy and Space Science Institute (Republic of Korea). Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The observatory was made possible by the generous financial support of the W. M. Keck Foundation. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Maunakea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. This work has made use of data from the European Space Agency (ESA) mission Gaia, processed by the Gaia Data Processing and Analysis Consortium (DPAC). Funding for the DPAC has been provided by the national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This research has made use of the SIMBAD database and the VizieR catalog access tool, both operated at the CDS, Strasbourg, France. This research has made use of the Washington Double Star Catalog maintained at the U.S. Naval Observatory. The authors have no relevant financial interests and no other potential conflicts of interest to disclose.

Attached Files

Published - 015006_1.pdf

Submitted - 1910.08659.pdf

Files

015006_1.pdf

Files (28.5 MB)

Name	Size	Download all
015006_1.pdf md5:e1be13600da4a17e8c75bb1d6a91729d	25.1 MB	Preview Download
1910.08659.pdf md5:1ceb9c44e30b7ab7a289cf606115710b	3.4 MB	Preview Download

Additional details

	All versions	This version
Views	0	0
Downloads	0	0
Data volume	0 Bytes	0 Bytes